The m68k-elf compiler chokes on this code when compiling for PIC as

compile_regex is one big function (relative function calls further
than cpu32 can do).

The solution was to re-order the code a little to reduce the size of these
relative calls.

So the total sum of the changes is:

* Move compile_regex to the end of the file
* make store_op1 an inline

Unfortunately CVS diff doesn't show this and makes it look like the whole
file has been severely hacked.  It hasn't.

libc/misc/regex/regex.c

@@ -1832,3898 +1832,3897 @@ int num_regs;
 
 #endif							/* not MATCH_MAY_ALLOCATE */
 
-static boolean group_in_compile_stack _RE_ARGS((compile_stack_type
-												compile_stack,
+/* Subroutines for `regex_compile'.  */
 
-												regnum_t regnum));
+/* Store OP at LOC followed by two-byte integer parameter ARG.  */
 
-/* `regex_compile' compiles PATTERN (of length SIZE) according to SYNTAX.
-   Returns one of error codes defined in `regex.h', or zero for success.
+static inline void store_op1(op, loc, arg)
+re_opcode_t op;
+unsigned char *loc;
+int arg;
+{
+	*loc = (unsigned char) op;
+	STORE_NUMBER(loc + 1, arg);
+}
 
-   Assumes the `allocated' (and perhaps `buffer') and `translate'
-   fields are set in BUFP on entry.
 
-   If it succeeds, results are put in BUFP (if it returns an error, the
-   contents of BUFP are undefined):
-     `buffer' is the compiled pattern;
-     `syntax' is set to SYNTAX;
-     `used' is set to the length of the compiled pattern;
-     `fastmap_accurate' is zero;
-     `re_nsub' is the number of subexpressions in PATTERN;
-     `not_bol' and `not_eol' are zero;
+/* Like `store_op1', but for two two-byte parameters ARG1 and ARG2.  */
 
-   The `fastmap' and `newline_anchor' fields are neither
-   examined nor set.  */
+static void store_op2(op, loc, arg1, arg2)
+re_opcode_t op;
+unsigned char *loc;
+int arg1, arg2;
+{
+	*loc = (unsigned char) op;
+	STORE_NUMBER(loc + 1, arg1);
+	STORE_NUMBER(loc + 3, arg2);
+}
 
-/* Return, freeing storage we allocated.  */
-#define FREE_STACK_RETURN(value)		\
-  return (free (compile_stack.stack), value)
 
-static reg_errcode_t regex_compile(pattern, size, syntax, bufp)
-const char *pattern;
-size_t size;
-reg_syntax_t syntax;
-struct re_pattern_buffer *bufp;
+/* Copy the bytes from LOC to END to open up three bytes of space at LOC
+   for OP followed by two-byte integer parameter ARG.  */
+
+static void insert_op1(op, loc, arg, end)
+re_opcode_t op;
+unsigned char *loc;
+int arg;
+unsigned char *end;
 {
-	/* We fetch characters from PATTERN here.  Even though PATTERN is
-	   `char *' (i.e., signed), we declare these variables as unsigned, so
-	   they can be reliably used as array indices.  */
-	register unsigned char c, c1;
+	register unsigned char *pfrom = end;
+	register unsigned char *pto = end + 3;
 
-	/* A random temporary spot in PATTERN.  */
-	const char *p1;
+	while (pfrom != loc)
+		*--pto = *--pfrom;
 
-	/* Points to the end of the buffer, where we should append.  */
-	register unsigned char *b;
+	store_op1(op, loc, arg);
+}
 
-	/* Keeps track of unclosed groups.  */
-	compile_stack_type compile_stack;
 
-	/* Points to the current (ending) position in the pattern.  */
-	const char *p = pattern;
-	const char *pend = pattern + size;
+/* Like `insert_op1', but for two two-byte parameters ARG1 and ARG2.  */
 
-	/* How to translate the characters in the pattern.  */
-	RE_TRANSLATE_TYPE translate = bufp->translate;
+static void insert_op2(op, loc, arg1, arg2, end)
+re_opcode_t op;
+unsigned char *loc;
+int arg1, arg2;
+unsigned char *end;
+{
+	register unsigned char *pfrom = end;
+	register unsigned char *pto = end + 5;
 
-	/* Address of the count-byte of the most recently inserted `exactn'
-	   command.  This makes it possible to tell if a new exact-match
-	   character can be added to that command or if the character requires
-	   a new `exactn' command.  */
-	unsigned char *pending_exact = 0;
+	while (pfrom != loc)
+		*--pto = *--pfrom;
 
-	/* Address of start of the most recently finished expression.
-	   This tells, e.g., postfix * where to find the start of its
-	   operand.  Reset at the beginning of groups and alternatives.  */
-	unsigned char *laststart = 0;
+	store_op2(op, loc, arg1, arg2);
+}
 
-	/* Address of beginning of regexp, or inside of last group.  */
-	unsigned char *begalt;
 
-	/* Place in the uncompiled pattern (i.e., the {) to
-	   which to go back if the interval is invalid.  */
-	const char *beg_interval;
+/* P points to just after a ^ in PATTERN.  Return true if that ^ comes
+   after an alternative or a begin-subexpression.  We assume there is at
+   least one character before the ^.  */
 
-	/* Address of the place where a forward jump should go to the end of
-	   the containing expression.  Each alternative of an `or' -- except the
-	   last -- ends with a forward jump of this sort.  */
-	unsigned char *fixup_alt_jump = 0;
+static boolean at_begline_loc_p(pattern, p, syntax)
+const char *pattern, *p;
+reg_syntax_t syntax;
+{
+	const char *prev = p - 2;
+	boolean prev_prev_backslash = prev > pattern && prev[-1] == '\\';
 
-	/* Counts open-groups as they are encountered.  Remembered for the
-	   matching close-group on the compile stack, so the same register
-	   number is put in the stop_memory as the start_memory.  */
-	regnum_t regnum = 0;
+	return
+		/* After a subexpression?  */
+		(*prev == '(' && (syntax & RE_NO_BK_PARENS || prev_prev_backslash))
+		/* After an alternative?  */
+		|| (*prev == '|'
+			&& (syntax & RE_NO_BK_VBAR || prev_prev_backslash));
+}
 
-#ifdef DEBUG
-	DEBUG_PRINT1("\nCompiling pattern: ");
-	if (debug) {
-		unsigned debug_count;
 
-		for (debug_count = 0; debug_count < size; debug_count++)
-			putchar(pattern[debug_count]);
-		putchar('\n');
-	}
-#endif							/* DEBUG */
+/* The dual of at_begline_loc_p.  This one is for $.  We assume there is
+   at least one character after the $, i.e., `P < PEND'.  */
 
-	/* Initialize the compile stack.  */
-	compile_stack.stack =
-		TALLOC(INIT_COMPILE_STACK_SIZE, compile_stack_elt_t);
-	if (compile_stack.stack == NULL)
-		return REG_ESPACE;
+static boolean at_endline_loc_p(p, pend, syntax)
+const char *p, *pend;
+reg_syntax_t syntax;
+{
+	const char *next = p;
+	boolean next_backslash = *next == '\\';
+	const char *next_next = p + 1 < pend ? p + 1 : 0;
 
-	compile_stack.size = INIT_COMPILE_STACK_SIZE;
-	compile_stack.avail = 0;
+	return
+		/* Before a subexpression?  */
+		(syntax & RE_NO_BK_PARENS ? *next == ')'
+		 : next_backslash && next_next && *next_next == ')')
+		/* Before an alternative?  */
+		|| (syntax & RE_NO_BK_VBAR ? *next == '|'
+			: next_backslash && next_next && *next_next == '|');
+}
 
-	/* Initialize the pattern buffer.  */
-	bufp->syntax = syntax;
-	bufp->fastmap_accurate = 0;
-	bufp->not_bol = bufp->not_eol = 0;
 
-	/* Set `used' to zero, so that if we return an error, the pattern
-	   printer (for debugging) will think there's no pattern.  We reset it
-	   at the end.  */
-	bufp->used = 0;
+/* Returns true if REGNUM is in one of COMPILE_STACK's elements and
+   false if it's not.  */
 
-	/* Always count groups, whether or not bufp->no_sub is set.  */
-	bufp->re_nsub = 0;
+static boolean group_in_compile_stack _RE_ARGS((compile_stack_type
+												compile_stack,
+												regnum_t regnum));
 
-#if !defined emacs && !defined SYNTAX_TABLE
-	/* Initialize the syntax table.  */
-	init_syntax_once();
-#endif
+static boolean group_in_compile_stack(compile_stack, regnum)
+compile_stack_type compile_stack;
+regnum_t regnum;
+{
+	int this_element;
 
-	if (bufp->allocated == 0) {
-		if (bufp->buffer) {		/* If zero allocated, but buffer is non-null, try to realloc
-								   enough space.  This loses if buffer's address is bogus, but
-								   that is the user's responsibility.  */
-			RETALLOC(bufp->buffer, INIT_BUF_SIZE, unsigned char);
-		} else {				/* Caller did not allocate a buffer.  Do it for them.  */
-			bufp->buffer = TALLOC(INIT_BUF_SIZE, unsigned char);
-		}
-		if (!bufp->buffer)
-			FREE_STACK_RETURN(REG_ESPACE);
+	for (this_element = compile_stack.avail - 1;
+		 this_element >= 0; this_element--)
+		if (compile_stack.stack[this_element].regnum == regnum)
+			return true;
 
-		bufp->allocated = INIT_BUF_SIZE;
-	}
+	return false;
+}
 
-	begalt = b = bufp->buffer;
 
-	/* Loop through the uncompiled pattern until we're at the end.  */
-	while (p != pend) {
-		PATFETCH(c);
+/* Read the ending character of a range (in a bracket expression) from the
+   uncompiled pattern *P_PTR (which ends at PEND).  We assume the
+   starting character is in `P[-2]'.  (`P[-1]' is the character `-'.)
+   Then we set the translation of all bits between the starting and
+   ending characters (inclusive) in the compiled pattern B.
 
-		switch (c) {
-		case '^':
-		{
-			if (				/* If at start of pattern, it's an operator.  */
-				   p == pattern + 1
-				   /* If context independent, it's an operator.  */
-				   || syntax & RE_CONTEXT_INDEP_ANCHORS
-				   /* Otherwise, depends on what's come before.  */
-				   || at_begline_loc_p(pattern, p, syntax))
-				BUF_PUSH(begline);
-			else
-				goto normal_char;
-		}
-			break;
+   Return an error code.
 
+   We use these short variable names so we can use the same macros as
+   `regex_compile' itself.  */
 
-		case '$':
-		{
-			if (				/* If at end of pattern, it's an operator.  */
-				   p == pend
-				   /* If context independent, it's an operator.  */
-				   || syntax & RE_CONTEXT_INDEP_ANCHORS
-				   /* Otherwise, depends on what's next.  */
-				   || at_endline_loc_p(p, pend, syntax))
-				BUF_PUSH(endline);
-			else
-				goto normal_char;
-		}
-			break;
+static reg_errcode_t compile_range(p_ptr, pend, translate, syntax, b)
+const char **p_ptr, *pend;
+RE_TRANSLATE_TYPE translate;
+reg_syntax_t syntax;
+unsigned char *b;
+{
+	unsigned this_char;
 
+	const char *p = *p_ptr;
+	reg_errcode_t ret;
+	char range_start[2];
+	char range_end[2];
+	char ch[2];
 
-		case '+':
-		case '?':
-			if ((syntax & RE_BK_PLUS_QM)
-				|| (syntax & RE_LIMITED_OPS))
-				goto normal_char;
-		  handle_plus:
-		case '*':
-			/* If there is no previous pattern... */
-			if (!laststart) {
-				if (syntax & RE_CONTEXT_INVALID_OPS)
-					FREE_STACK_RETURN(REG_BADRPT);
-				else if (!(syntax & RE_CONTEXT_INDEP_OPS))
-					goto normal_char;
-			}
+	if (p == pend)
+		return REG_ERANGE;
 
-			{
-				/* Are we optimizing this jump?  */
-				boolean keep_string_p = false;
+	/* Fetch the endpoints without translating them; the
+	   appropriate translation is done in the bit-setting loop below.  */
+	range_start[0] = p[-2];
+	range_start[1] = '\0';
+	range_end[0] = p[0];
+	range_end[1] = '\0';
 
-				/* 1 means zero (many) matches is allowed.  */
-				char zero_times_ok = 0, many_times_ok = 0;
+	/* Have to increment the pointer into the pattern string, so the
+	   caller isn't still at the ending character.  */
+	(*p_ptr)++;
 
-				/* If there is a sequence of repetition chars, collapse it
-				   down to just one (the right one).  We can't combine
-				   interval operators with these because of, e.g., `a{2}*',
-				   which should only match an even number of `a's.  */
+	/* Report an error if the range is empty and the syntax prohibits this.  */
+	ret = syntax & RE_NO_EMPTY_RANGES ? REG_ERANGE : REG_NOERROR;
 
-				for (;;) {
-					zero_times_ok |= c != '+';
-					many_times_ok |= c != '?';
+	/* Here we see why `this_char' has to be larger than an `unsigned
+	   char' -- we would otherwise go into an infinite loop, since all
+	   characters <= 0xff.  */
+	ch[1] = '\0';
+	for (this_char = 0; this_char <= (unsigned char) -1; ++this_char) {
+		ch[0] = this_char;
+		if (strcoll(range_start, ch) <= 0 && strcoll(ch, range_end) <= 0) {
+			SET_LIST_BIT(TRANSLATE(this_char));
+			ret = REG_NOERROR;
+		}
+	}
 
-					if (p == pend)
-						break;
+	return ret;
+}
+
+/* re_compile_fastmap computes a ``fastmap'' for the compiled pattern in
+   BUFP.  A fastmap records which of the (1 << BYTEWIDTH) possible
+   characters can start a string that matches the pattern.  This fastmap
+   is used by re_search to skip quickly over impossible starting points.
 
-					PATFETCH(c);
+   The caller must supply the address of a (1 << BYTEWIDTH)-byte data
+   area as BUFP->fastmap.
 
-					if (c == '*'
-						|| (!(syntax & RE_BK_PLUS_QM)
-							&& (c == '+' || c == '?')));
+   We set the `fastmap', `fastmap_accurate', and `can_be_null' fields in
+   the pattern buffer.
 
-					else if (syntax & RE_BK_PLUS_QM && c == '\\') {
-						if (p == pend)
-							FREE_STACK_RETURN(REG_EESCAPE);
+   Returns 0 if we succeed, -2 if an internal error.   */
 
-						PATFETCH(c1);
-						if (!(c1 == '+' || c1 == '?')) {
-							PATUNFETCH;
-							PATUNFETCH;
-							break;
-						}
+int re_compile_fastmap(bufp)
+struct re_pattern_buffer *bufp;
+{
+	int j, k;
 
-						c = c1;
-					} else {
-						PATUNFETCH;
-						break;
-					}
+#ifdef MATCH_MAY_ALLOCATE
+	fail_stack_type fail_stack;
+#endif
+#ifndef REGEX_MALLOC
+	char *destination;
+#endif
 
-					/* If we get here, we found another repeat character.  */
-				}
+	register char *fastmap = bufp->fastmap;
+	unsigned char *pattern = bufp->buffer;
+	unsigned char *p = pattern;
+	register unsigned char *pend = pattern + bufp->used;
 
-				/* Star, etc. applied to an empty pattern is equivalent
-				   to an empty pattern.  */
-				if (!laststart)
-					break;
+#ifdef REL_ALLOC
+	/* This holds the pointer to the failure stack, when
+	   it is allocated relocatably.  */
+	fail_stack_elt_t *failure_stack_ptr;
+#endif
 
-				/* Now we know whether or not zero matches is allowed
-				   and also whether or not two or more matches is allowed.  */
-				if (many_times_ok) {	/* More than one repetition is allowed, so put in at the
-										   end a backward relative jump from `b' to before the next
-										   jump we're going to put in below (which jumps from
-										   laststart to after this jump).
+	/* Assume that each path through the pattern can be null until
+	   proven otherwise.  We set this false at the bottom of switch
+	   statement, to which we get only if a particular path doesn't
+	   match the empty string.  */
+	boolean path_can_be_null = true;
 
-										   But if we are at the `*' in the exact sequence `.*\n',
-										   insert an unconditional jump backwards to the .,
-										   instead of the beginning of the loop.  This way we only
-										   push a failure point once, instead of every time
-										   through the loop.  */
-					assert(p - 1 > pattern);
+	/* We aren't doing a `succeed_n' to begin with.  */
+	boolean succeed_n_p = false;
 
-					/* Allocate the space for the jump.  */
-					GET_BUFFER_SPACE(3);
+	assert(fastmap != NULL && p != NULL);
 
-					/* We know we are not at the first character of the pattern,
-					   because laststart was nonzero.  And we've already
-					   incremented `p', by the way, to be the character after
-					   the `*'.  Do we have to do something analogous here
-					   for null bytes, because of RE_DOT_NOT_NULL?  */
-					if (TRANSLATE(*(p - 2)) == TRANSLATE('.')
-						&& zero_times_ok
-						&& p < pend && TRANSLATE(*p) == TRANSLATE('\n')
-						&& !(syntax & RE_DOT_NEWLINE)) {	/* We have .*\n.  */
-						STORE_JUMP(jump, b, laststart);
-						keep_string_p = true;
-					} else
-						/* Anything else.  */
-						STORE_JUMP(maybe_pop_jump, b, laststart - 3);
+	INIT_FAIL_STACK();
+	bzero(fastmap, 1 << BYTEWIDTH);	/* Assume nothing's valid.  */
+	bufp->fastmap_accurate = 1;	/* It will be when we're done.  */
+	bufp->can_be_null = 0;
 
-					/* We've added more stuff to the buffer.  */
-					b += 3;
-				}
+	while (1) {
+		if (p == pend || *p == succeed) {
+			/* We have reached the (effective) end of pattern.  */
+			if (!FAIL_STACK_EMPTY()) {
+				bufp->can_be_null |= path_can_be_null;
 
-				/* On failure, jump from laststart to b + 3, which will be the
-				   end of the buffer after this jump is inserted.  */
-				GET_BUFFER_SPACE(3);
-				INSERT_JUMP(keep_string_p ? on_failure_keep_string_jump
-							: on_failure_jump, laststart, b + 3);
-				pending_exact = 0;
-				b += 3;
+				/* Reset for next path.  */
+				path_can_be_null = true;
 
-				if (!zero_times_ok) {
-					/* At least one repetition is required, so insert a
-					   `dummy_failure_jump' before the initial
-					   `on_failure_jump' instruction of the loop. This
-					   effects a skip over that instruction the first time
-					   we hit that loop.  */
-					GET_BUFFER_SPACE(3);
-					INSERT_JUMP(dummy_failure_jump, laststart,
-								laststart + 6);
-					b += 3;
-				}
-			}
-			break;
+				p = fail_stack.stack[--fail_stack.avail].pointer;
 
+				continue;
+			} else
+				break;
+		}
 
-		case '.':
-			laststart = b;
-			BUF_PUSH(anychar);
-			break;
+		/* We should never be about to go beyond the end of the pattern.  */
+		assert(p < pend);
 
+		switch (SWITCH_ENUM_CAST((re_opcode_t) * p++)) {
 
-		case '[':
-		{
-			boolean had_char_class = false;
+			/* I guess the idea here is to simply not bother with a fastmap
+			   if a backreference is used, since it's too hard to figure out
+			   the fastmap for the corresponding group.  Setting
+			   `can_be_null' stops `re_search_2' from using the fastmap, so
+			   that is all we do.  */
+		case duplicate:
+			bufp->can_be_null = 1;
+			goto done;
 
-			if (p == pend)
-				FREE_STACK_RETURN(REG_EBRACK);
 
-			/* Ensure that we have enough space to push a charset: the
-			   opcode, the length count, and the bitset; 34 bytes in all.  */
-			GET_BUFFER_SPACE(34);
+			/* Following are the cases which match a character.  These end
+			   with `break'.  */
 
-			laststart = b;
+		case exactn:
+			fastmap[p[1]] = 1;
+			break;
 
-			/* We test `*p == '^' twice, instead of using an if
-			   statement, so we only need one BUF_PUSH.  */
-			BUF_PUSH(*p == '^' ? charset_not : charset);
-			if (*p == '^')
-				p++;
 
-			/* Remember the first position in the bracket expression.  */
-			p1 = p;
+		case charset:
+			for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
+				if (p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH)))
+					fastmap[j] = 1;
+			break;
 
-			/* Push the number of bytes in the bitmap.  */
-			BUF_PUSH((1 << BYTEWIDTH) / BYTEWIDTH);
 
-			/* Clear the whole map.  */
-			bzero(b, (1 << BYTEWIDTH) / BYTEWIDTH);
+		case charset_not:
+			/* Chars beyond end of map must be allowed.  */
+			for (j = *p * BYTEWIDTH; j < (1 << BYTEWIDTH); j++)
+				fastmap[j] = 1;
 
-			/* charset_not matches newline according to a syntax bit.  */
-			if ((re_opcode_t) b[-2] == charset_not
-				&& (syntax & RE_HAT_LISTS_NOT_NEWLINE)) SET_LIST_BIT('\n');
+			for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
+				if (!(p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH))))
+					fastmap[j] = 1;
+			break;
 
-			/* Read in characters and ranges, setting map bits.  */
-			for (;;) {
-				if (p == pend)
-					FREE_STACK_RETURN(REG_EBRACK);
 
-				PATFETCH(c);
+		case wordchar:
+			for (j = 0; j < (1 << BYTEWIDTH); j++)
+				if (SYNTAX(j) == Sword)
+					fastmap[j] = 1;
+			break;
 
-				/* \ might escape characters inside [...] and [^...].  */
-				if ((syntax & RE_BACKSLASH_ESCAPE_IN_LISTS) && c == '\\') {
-					if (p == pend)
-						FREE_STACK_RETURN(REG_EESCAPE);
 
-					PATFETCH(c1);
-					SET_LIST_BIT(c1);
-					continue;
-				}
+		case notwordchar:
+			for (j = 0; j < (1 << BYTEWIDTH); j++)
+				if (SYNTAX(j) != Sword)
+					fastmap[j] = 1;
+			break;
 
-				/* Could be the end of the bracket expression.  If it's
-				   not (i.e., when the bracket expression is `[]' so
-				   far), the ']' character bit gets set way below.  */
-				if (c == ']' && p != p1 + 1)
-					break;
 
-				/* Look ahead to see if it's a range when the last thing
-				   was a character class.  */
-				if (had_char_class && c == '-' && *p != ']')
-					FREE_STACK_RETURN(REG_ERANGE);
+		case anychar:
+		{
+			int fastmap_newline = fastmap['\n'];
 
-				/* Look ahead to see if it's a range when the last thing
-				   was a character: if this is a hyphen not at the
-				   beginning or the end of a list, then it's the range
-				   operator.  */
-				if (c == '-' && !(p - 2 >= pattern && p[-2] == '[')
-					&& !(p - 3 >= pattern && p[-3] == '[' && p[-2] == '^')
-					&& *p != ']') {
-					reg_errcode_t ret
-						= compile_range(&p, pend, translate, syntax, b);
+			/* `.' matches anything ...  */
+			for (j = 0; j < (1 << BYTEWIDTH); j++)
+				fastmap[j] = 1;
 
-					if (ret != REG_NOERROR)
-						FREE_STACK_RETURN(ret);
-				}
+			/* ... except perhaps newline.  */
+			if (!(bufp->syntax & RE_DOT_NEWLINE))
+				fastmap['\n'] = fastmap_newline;
 
-				else if (p[0] == '-' && p[1] != ']') {	/* This handles ranges made up of characters only.  */
-					reg_errcode_t ret;
+			/* Return if we have already set `can_be_null'; if we have,
+			   then the fastmap is irrelevant.  Something's wrong here.  */
+			else if (bufp->can_be_null)
+				goto done;
 
-					/* Move past the `-'.  */
-					PATFETCH(c1);
+			/* Otherwise, have to check alternative paths.  */
+			break;
+		}
 
-					ret = compile_range(&p, pend, translate, syntax, b);
-					if (ret != REG_NOERROR)
-						FREE_STACK_RETURN(ret);
-				}
+#ifdef emacs
+		case syntaxspec:
+			k = *p++;
+			for (j = 0; j < (1 << BYTEWIDTH); j++)
+				if (SYNTAX(j) == (enum syntaxcode) k)
+					fastmap[j] = 1;
+			break;
 
-				/* See if we're at the beginning of a possible character
-				   class.  */
 
-				else if (syntax & RE_CHAR_CLASSES && c == '[' && *p == ':') {	/* Leave room for the null.  */
-					char str[CHAR_CLASS_MAX_LENGTH + 1];
+		case notsyntaxspec:
+			k = *p++;
+			for (j = 0; j < (1 << BYTEWIDTH); j++)
+				if (SYNTAX(j) != (enum syntaxcode) k)
+					fastmap[j] = 1;
+			break;
 
-					PATFETCH(c);
-					c1 = 0;
 
-					/* If pattern is `[[:'.  */
-					if (p == pend)
-						FREE_STACK_RETURN(REG_EBRACK);
+			/* All cases after this match the empty string.  These end with
+			   `continue'.  */
 
-					for (;;) {
-						PATFETCH(c);
-						if ((c == ':' && *p == ']') || p == pend)
-							break;
-						if (c1 < CHAR_CLASS_MAX_LENGTH)
-							str[c1++] = c;
-						else
-							/* This is in any case an invalid class name.  */
-							str[0] = '\0';
-					}
-					str[c1] = '\0';
 
-					/* If isn't a word bracketed by `[:' and `:]':
-					   undo the ending character, the letters, and leave
-					   the leading `:' and `[' (but set bits for them).  */
-					if (c == ':' && *p == ']') {
-#if defined _LIBC || WIDE_CHAR_SUPPORT
-						boolean is_lower = STREQ(str, "lower");
-						boolean is_upper = STREQ(str, "upper");
-						wctype_t wt;
-						int ch;
+		case before_dot:
+		case at_dot:
+		case after_dot:
+			continue;
+#endif							/* emacs */
 
-						wt = IS_CHAR_CLASS(str);
-						if (wt == 0)
-							FREE_STACK_RETURN(REG_ECTYPE);
 
-						/* Throw away the ] at the end of the character
-						   class.  */
-						PATFETCH(c);
+		case no_op:
+		case begline:
+		case endline:
+		case begbuf:
+		case endbuf:
+		case wordbound:
+		case notwordbound:
+		case wordbeg:
+		case wordend:
+		case push_dummy_failure:
+			continue;
 
-						if (p == pend)
-							FREE_STACK_RETURN(REG_EBRACK);
 
-						for (ch = 0; ch < 1 << BYTEWIDTH; ++ch) {
-# ifdef _LIBC
-							if (__iswctype(__btowc(ch), wt))
-								SET_LIST_BIT(ch);
-# else
-							if (iswctype(btowc(ch), wt))
-								SET_LIST_BIT(ch);
-# endif
+		case jump_n:
+		case pop_failure_jump:
+		case maybe_pop_jump:
+		case jump:
+		case jump_past_alt:
+		case dummy_failure_jump:
+			EXTRACT_NUMBER_AND_INCR(j, p);
+			p += j;
+			if (j > 0)
+				continue;
 
-							if (translate && (is_upper || is_lower)
-								&& (ISUPPER(ch) || ISLOWER(ch)))
-								SET_LIST_BIT(ch);
-						}
+			/* Jump backward implies we just went through the body of a
+			   loop and matched nothing.  Opcode jumped to should be
+			   `on_failure_jump' or `succeed_n'.  Just treat it like an
+			   ordinary jump.  For a * loop, it has pushed its failure
+			   point already; if so, discard that as redundant.  */
+			if ((re_opcode_t) * p != on_failure_jump
+				&& (re_opcode_t) * p != succeed_n)
+				continue;
 
-						had_char_class = true;
-#else
-						int ch;
-						boolean is_alnum = STREQ(str, "alnum");
-						boolean is_alpha = STREQ(str, "alpha");
-						boolean is_blank = STREQ(str, "blank");
-						boolean is_cntrl = STREQ(str, "cntrl");
-						boolean is_digit = STREQ(str, "digit");
-						boolean is_graph = STREQ(str, "graph");
-						boolean is_lower = STREQ(str, "lower");
-						boolean is_print = STREQ(str, "print");
-						boolean is_punct = STREQ(str, "punct");
-						boolean is_space = STREQ(str, "space");
-						boolean is_upper = STREQ(str, "upper");
-						boolean is_xdigit = STREQ(str, "xdigit");
+			p++;
+			EXTRACT_NUMBER_AND_INCR(j, p);
+			p += j;
 
-						if (!IS_CHAR_CLASS(str))
-							FREE_STACK_RETURN(REG_ECTYPE);
+			/* If what's on the stack is where we are now, pop it.  */
+			if (!FAIL_STACK_EMPTY()
+				&& fail_stack.stack[fail_stack.avail - 1].pointer == p)
+				fail_stack.avail--;
 
-						/* Throw away the ] at the end of the character
-						   class.  */
-						PATFETCH(c);
+			continue;
 
-						if (p == pend)
-							FREE_STACK_RETURN(REG_EBRACK);
 
-						for (ch = 0; ch < 1 << BYTEWIDTH; ch++) {
-							/* This was split into 3 if's to
-							   avoid an arbitrary limit in some compiler.  */
-							if ((is_alnum && ISALNUM(ch))
-								|| (is_alpha && ISALPHA(ch))
-								|| (is_blank && ISBLANK(ch))
-								|| (is_cntrl && ISCNTRL(ch)))
-								SET_LIST_BIT(ch);
-							if ((is_digit && ISDIGIT(ch))
-								|| (is_graph && ISGRAPH(ch))
-								|| (is_lower && ISLOWER(ch))
-								|| (is_print && ISPRINT(ch)))
-								SET_LIST_BIT(ch);
-							if ((is_punct && ISPUNCT(ch))
-								|| (is_space && ISSPACE(ch))
-								|| (is_upper && ISUPPER(ch))
-								|| (is_xdigit && ISXDIGIT(ch)))
-								SET_LIST_BIT(ch);
-							if (translate && (is_upper || is_lower)
-								&& (ISUPPER(ch) || ISLOWER(ch)))
-								SET_LIST_BIT(ch);
-						}
-						had_char_class = true;
-#endif							/* libc || wctype.h */
-					} else {
-						c1++;
-						while (c1--)
-							PATUNFETCH;
-						SET_LIST_BIT('[');
-						SET_LIST_BIT(':');
-						had_char_class = false;
-					}
-				} else {
-					had_char_class = false;
-					SET_LIST_BIT(c);
+		case on_failure_jump:
+		case on_failure_keep_string_jump:
+		  handle_on_failure_jump:
+			EXTRACT_NUMBER_AND_INCR(j, p);
+
+			/* For some patterns, e.g., `(a?)?', `p+j' here points to the
+			   end of the pattern.  We don't want to push such a point,
+			   since when we restore it above, entering the switch will
+			   increment `p' past the end of the pattern.  We don't need
+			   to push such a point since we obviously won't find any more
+			   fastmap entries beyond `pend'.  Such a pattern can match
+			   the null string, though.  */
+			if (p + j < pend) {
+				if (!PUSH_PATTERN_OP(p + j, fail_stack)) {
+					RESET_FAIL_STACK();
+					return -2;
 				}
+			} else
+				bufp->can_be_null = 1;
+
+			if (succeed_n_p) {
+				EXTRACT_NUMBER_AND_INCR(k, p);	/* Skip the n.  */
+				succeed_n_p = false;
 			}
 
-			/* Discard any (non)matching list bytes that are all 0 at the
-			   end of the map.  Decrease the map-length byte too.  */
-			while ((int) b[-1] > 0 && b[b[-1] - 1] == 0)
-				b[-1]--;
-			b += b[-1];
-		}
-			break;
+			continue;
 
 
-		case '(':
-			if (syntax & RE_NO_BK_PARENS)
-				goto handle_open;
-			else
-				goto normal_char;
+		case succeed_n:
+			/* Get to the number of times to succeed.  */
+			p += 2;
 
+			/* Increment p past the n for when k != 0.  */
+			EXTRACT_NUMBER_AND_INCR(k, p);
+			if (k == 0) {
+				p -= 4;
+				succeed_n_p = true;	/* Spaghetti code alert.  */
+				goto handle_on_failure_jump;
+			}
+			continue;
 
-		case ')':
-			if (syntax & RE_NO_BK_PARENS)
-				goto handle_close;
-			else
-				goto normal_char;
 
+		case set_number_at:
+			p += 4;
+			continue;
 
-		case '\n':
-			if (syntax & RE_NEWLINE_ALT)
-				goto handle_alt;
-			else
-				goto normal_char;
 
+		case start_memory:
+		case stop_memory:
+			p += 2;
+			continue;
 
-		case '|':
-			if (syntax & RE_NO_BK_VBAR)
-				goto handle_alt;
-			else
-				goto normal_char;
 
+		default:
+			abort();			/* We have listed all the cases.  */
+		}						/* switch *p++ */
 
-		case '{':
-			if (syntax & RE_INTERVALS && syntax & RE_NO_BK_BRACES)
-				goto handle_interval;
-			else
-				goto normal_char;
+		/* Getting here means we have found the possible starting
+		   characters for one path of the pattern -- and that the empty
+		   string does not match.  We need not follow this path further.
+		   Instead, look at the next alternative (remembered on the
+		   stack), or quit if no more.  The test at the top of the loop
+		   does these things.  */
+		path_can_be_null = false;
+		p = pend;
+	}							/* while p */
 
+	/* Set `can_be_null' for the last path (also the first path, if the
+	   pattern is empty).  */
+	bufp->can_be_null |= path_can_be_null;
 
-		case '\\':
-			if (p == pend)
-				FREE_STACK_RETURN(REG_EESCAPE);
+  done:
+	RESET_FAIL_STACK();
+	return 0;
+}								/* re_compile_fastmap */
 
-			/* Do not translate the character after the \, so that we can
-			   distinguish, e.g., \B from \b, even if we normally would
-			   translate, e.g., B to b.  */
-			PATFETCH_RAW(c);
+#ifdef _LIBC
+weak_alias(__re_compile_fastmap, re_compile_fastmap)
+#endif
+/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
+   ENDS.  Subsequent matches using PATTERN_BUFFER and REGS will use
+   this memory for recording register information.  STARTS and ENDS
+   must be allocated using the malloc library routine, and must each
+   be at least NUM_REGS * sizeof (regoff_t) bytes long.
 
-			switch (c) {
-			case '(':
-				if (syntax & RE_NO_BK_PARENS)
-					goto normal_backslash;
+   If NUM_REGS == 0, then subsequent matches should allocate their own
+   register data.
 
-			  handle_open:
-				bufp->re_nsub++;
-				regnum++;
+   Unless this function is called, the first search or match using
+   PATTERN_BUFFER will allocate its own register data, without
+   freeing the old data.  */
+void re_set_registers(bufp, regs, num_regs, starts, ends)
+struct re_pattern_buffer *bufp;
+struct re_registers *regs;
+unsigned num_regs;
+regoff_t *starts, *ends;
+{
+	if (num_regs) {
+		bufp->regs_allocated = REGS_REALLOCATE;
+		regs->num_regs = num_regs;
+		regs->start = starts;
+		regs->end = ends;
+	} else {
+		bufp->regs_allocated = REGS_UNALLOCATED;
+		regs->num_regs = 0;
+		regs->start = regs->end = (regoff_t *) 0;
+	}
+}
 
-				if (COMPILE_STACK_FULL) {
-					RETALLOC(compile_stack.stack, compile_stack.size << 1,
-							 compile_stack_elt_t);
-					if (compile_stack.stack == NULL)
-						return REG_ESPACE;
+#ifdef _LIBC
+weak_alias(__re_set_registers, re_set_registers)
+#endif
+/* Searching routines.  */
+/* Like re_search_2, below, but only one string is specified, and
+   doesn't let you say where to stop matching. */
+int re_search(bufp, string, size, startpos, range, regs)
+struct re_pattern_buffer *bufp;
+const char *string;
+int size, startpos, range;
+struct re_registers *regs;
+{
+	return re_search_2(bufp, NULL, 0, string, size, startpos, range,
+					   regs, size);
+}
 
-					compile_stack.size <<= 1;
-				}
+#ifdef _LIBC
+weak_alias(__re_search, re_search)
+#endif
+/* Using the compiled pattern in BUFP->buffer, first tries to match the
+   virtual concatenation of STRING1 and STRING2, starting first at index
+   STARTPOS, then at STARTPOS + 1, and so on.
 
-				/* These are the values to restore when we hit end of this
-				   group.  They are all relative offsets, so that if the
-				   whole pattern moves because of realloc, they will still
-				   be valid.  */
-				COMPILE_STACK_TOP.begalt_offset = begalt - bufp->buffer;
-				COMPILE_STACK_TOP.fixup_alt_jump
-					=
-					fixup_alt_jump ? fixup_alt_jump - bufp->buffer + 1 : 0;
-				COMPILE_STACK_TOP.laststart_offset = b - bufp->buffer;
-				COMPILE_STACK_TOP.regnum = regnum;
+   STRING1 and STRING2 have length SIZE1 and SIZE2, respectively.
 
-				/* We will eventually replace the 0 with the number of
-				   groups inner to this one.  But do not push a
-				   start_memory for groups beyond the last one we can
-				   represent in the compiled pattern.  */
-				if (regnum <= MAX_REGNUM) {
-					COMPILE_STACK_TOP.inner_group_offset =
-						b - bufp->buffer + 2;
-					BUF_PUSH_3(start_memory, regnum, 0);
-				}
+   RANGE is how far to scan while trying to match.  RANGE = 0 means try
+   only at STARTPOS; in general, the last start tried is STARTPOS +
+   RANGE.
 
-				compile_stack.avail++;
+   In REGS, return the indices of the virtual concatenation of STRING1
+   and STRING2 that matched the entire BUFP->buffer and its contained
+   subexpressions.
 
-				fixup_alt_jump = 0;
-				laststart = 0;
-				begalt = b;
-				/* If we've reached MAX_REGNUM groups, then this open
-				   won't actually generate any code, so we'll have to
-				   clear pending_exact explicitly.  */
-				pending_exact = 0;
-				break;
+   Do not consider matching one past the index STOP in the virtual
+   concatenation of STRING1 and STRING2.
 
+   We return either the position in the strings at which the match was
+   found, -1 if no match, or -2 if error (such as failure
+   stack overflow).  */
+int
+re_search_2(bufp, string1, size1, string2, size2, startpos, range, regs,
+			stop)
+struct re_pattern_buffer *bufp;
+const char *string1, *string2;
+int size1, size2;
+int startpos;
+int range;
+struct re_registers *regs;
+int stop;
+{
+	int val;
+	register char *fastmap = bufp->fastmap;
+	register RE_TRANSLATE_TYPE translate = bufp->translate;
+	int total_size = size1 + size2;
+	int endpos = startpos + range;
 
-			case ')':
-				if (syntax & RE_NO_BK_PARENS)
-					goto normal_backslash;
+	/* Check for out-of-range STARTPOS.  */
+	if (startpos < 0 || startpos > total_size)
+		return -1;
 
-				if (COMPILE_STACK_EMPTY) {
-					if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
-						goto normal_backslash;
-					else
-						FREE_STACK_RETURN(REG_ERPAREN);
-				}
+	/* Fix up RANGE if it might eventually take us outside
+	   the virtual concatenation of STRING1 and STRING2.
+	   Make sure we won't move STARTPOS below 0 or above TOTAL_SIZE.  */
+	if (endpos < 0)
+		range = 0 - startpos;
+	else if (endpos > total_size)
+		range = total_size - startpos;
 
-			  handle_close:
-				if (fixup_alt_jump) {	/* Push a dummy failure point at the end of the
-										   alternative for a possible future
-										   `pop_failure_jump' to pop.  See comments at
-										   `push_dummy_failure' in `re_match_2'.  */
-					BUF_PUSH(push_dummy_failure);
+	/* If the search isn't to be a backwards one, don't waste time in a
+	   search for a pattern that must be anchored.  */
+	if (bufp->used > 0 && range > 0
+		&& ((re_opcode_t) bufp->buffer[0] == begbuf
+			/* `begline' is like `begbuf' if it cannot match at newlines.  */
+			|| ((re_opcode_t) bufp->buffer[0] == begline
+				&& !bufp->newline_anchor))) {
+		if (startpos > 0)
+			return -1;
+		else
+			range = 1;
+	}
+#ifdef emacs
+	/* In a forward search for something that starts with \=.
+	   don't keep searching past point.  */
+	if (bufp->used > 0 && (re_opcode_t) bufp->buffer[0] == at_dot
+		&& range > 0) {
+		range = PT - startpos;
+		if (range <= 0)
+			return -1;
+	}
+#endif							/* emacs */
 
-					/* We allocated space for this jump when we assigned
-					   to `fixup_alt_jump', in the `handle_alt' case below.  */
-					STORE_JUMP(jump_past_alt, fixup_alt_jump, b - 1);
-				}
+	/* Update the fastmap now if not correct already.  */
+	if (fastmap && !bufp->fastmap_accurate)
+		if (re_compile_fastmap(bufp) == -2)
+			return -2;
 
-				/* See similar code for backslashed left paren above.  */
-				if (COMPILE_STACK_EMPTY) {
-					if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
-						goto normal_char;
-					else
-						FREE_STACK_RETURN(REG_ERPAREN);
-				}
+	/* Loop through the string, looking for a place to start matching.  */
+	for (;;) {
+		/* If a fastmap is supplied, skip quickly over characters that
+		   cannot be the start of a match.  If the pattern can match the
+		   null string, however, we don't need to skip characters; we want
+		   the first null string.  */
+		if (fastmap && startpos < total_size && !bufp->can_be_null) {
+			if (range > 0) {	/* Searching forwards.  */
+				register const char *d;
+				register int lim = 0;
+				int irange = range;
 
-				/* Since we just checked for an empty stack above, this
-				   ``can't happen''.  */
-				assert(compile_stack.avail != 0);
-				{
-					/* We don't just want to restore into `regnum', because
-					   later groups should continue to be numbered higher,
-					   as in `(ab)c(de)' -- the second group is #2.  */
-					regnum_t this_group_regnum;
+				if (startpos < size1 && startpos + range >= size1)
+					lim = range - (size1 - startpos);
 
-					compile_stack.avail--;
-					begalt =
-						bufp->buffer + COMPILE_STACK_TOP.begalt_offset;
-					fixup_alt_jump =
-						COMPILE_STACK_TOP.fixup_alt_jump ? bufp->buffer +
-						COMPILE_STACK_TOP.fixup_alt_jump - 1 : 0;
-					laststart =
-						bufp->buffer + COMPILE_STACK_TOP.laststart_offset;
-					this_group_regnum = COMPILE_STACK_TOP.regnum;
-					/* If we've reached MAX_REGNUM groups, then this open
-					   won't actually generate any code, so we'll have to
-					   clear pending_exact explicitly.  */
-					pending_exact = 0;
-
-					/* We're at the end of the group, so now we know how many
-					   groups were inside this one.  */
-					if (this_group_regnum <= MAX_REGNUM) {
-						unsigned char *inner_group_loc
-
-							=
-							bufp->buffer +
-							COMPILE_STACK_TOP.inner_group_offset;
-
-						*inner_group_loc = regnum - this_group_regnum;
-						BUF_PUSH_3(stop_memory, this_group_regnum,
-								   regnum - this_group_regnum);
-					}
-				}
-				break;
-
-
-			case '|':			/* `\|'.  */
-				if (syntax & RE_LIMITED_OPS || syntax & RE_NO_BK_VBAR)
-					goto normal_backslash;
-			  handle_alt:
-				if (syntax & RE_LIMITED_OPS)
-					goto normal_char;
-
-				/* Insert before the previous alternative a jump which
-				   jumps to this alternative if the former fails.  */
-				GET_BUFFER_SPACE(3);
-				INSERT_JUMP(on_failure_jump, begalt, b + 6);
-				pending_exact = 0;
-				b += 3;
-
-				/* The alternative before this one has a jump after it
-				   which gets executed if it gets matched.  Adjust that
-				   jump so it will jump to this alternative's analogous
-				   jump (put in below, which in turn will jump to the next
-				   (if any) alternative's such jump, etc.).  The last such
-				   jump jumps to the correct final destination.  A picture:
-				   _____ _____
-				   |   | |   |
-				   |   v |   v
-				   a | b   | c
-
-				   If we are at `b', then fixup_alt_jump right now points to a
-				   three-byte space after `a'.  We'll put in the jump, set
-				   fixup_alt_jump to right after `b', and leave behind three
-				   bytes which we'll fill in when we get to after `c'.  */
-
-				if (fixup_alt_jump)
-					STORE_JUMP(jump_past_alt, fixup_alt_jump, b);
-
-				/* Mark and leave space for a jump after this alternative,
-				   to be filled in later either by next alternative or
-				   when know we're at the end of a series of alternatives.  */
-				fixup_alt_jump = b;
-				GET_BUFFER_SPACE(3);
-				b += 3;
-
-				laststart = 0;
-				begalt = b;
-				break;
-
-
-			case '{':
-				/* If \{ is a literal.  */
-				if (!(syntax & RE_INTERVALS)
-					/* If we're at `\{' and it's not the open-interval
-					   operator.  */
-					|| ((syntax & RE_INTERVALS)
-						&& (syntax & RE_NO_BK_BRACES)) || (p - 2 == pattern
-														   && p == pend))
-					goto normal_backslash;
-
-			  handle_interval:
-				{
-					/* If got here, then the syntax allows intervals.  */
+				d =
+					(startpos >=
+					 size1 ? string2 - size1 : string1) + startpos;
 
-					/* At least (most) this many matches must be made.  */
-					int lower_bound = -1, upper_bound = -1;
+				/* Written out as an if-else to avoid testing `translate'
+				   inside the loop.  */
+				if (translate)
+					while (range > lim && !fastmap[(unsigned char)
+												   translate[
+															 (unsigned
+															  char) *d++]])
+						range--;
+				else
+					while (range > lim && !fastmap[(unsigned char) *d++])
+						range--;
 
-					beg_interval = p - 1;
+				startpos += irange - range;
+			} else {			/* Searching backwards.  */
 
-					if (p == pend) {
-						if (!(syntax & RE_INTERVALS)
-							&& (syntax & RE_NO_BK_BRACES)) goto
-								unfetch_interval;
-						else
-							FREE_STACK_RETURN(REG_EBRACE);
-					}
+				register char c = (size1 == 0 || startpos >= size1
+								   ? string2[startpos - size1]
+								   : string1[startpos]);
 
-					GET_UNSIGNED_NUMBER(lower_bound);
+				if (!fastmap[(unsigned char) TRANSLATE(c)])
+					goto advance;
+			}
+		}
 
-					if (c == ',') {
-						GET_UNSIGNED_NUMBER(upper_bound);
-						if ((!(syntax & RE_NO_BK_BRACES) && c != '\\')
-							|| ((syntax & RE_NO_BK_BRACES) && c != '}'))
-							FREE_STACK_RETURN(REG_BADBR);
+		/* If can't match the null string, and that's all we have left, fail.  */
+		if (range >= 0 && startpos == total_size && fastmap
+			&& !bufp->can_be_null) return -1;
 
-						if (upper_bound < 0)
-							upper_bound = RE_DUP_MAX;
-					} else
-						/* Interval such as `{1}' => match exactly once. */
-						upper_bound = lower_bound;
+		val = re_match_2_internal(bufp, string1, size1, string2, size2,
+								  startpos, regs, stop);
+#ifndef REGEX_MALLOC
+# ifdef C_ALLOCA
+		alloca(0);
+# endif
+#endif
 
-					if (lower_bound < 0 || upper_bound > RE_DUP_MAX
-						|| lower_bound > upper_bound) {
-						if (!(syntax & RE_INTERVALS)
-							&& (syntax & RE_NO_BK_BRACES)) goto
-								unfetch_interval;
-						else
-							FREE_STACK_RETURN(REG_BADBR);
-					}
+		if (val >= 0)
+			return startpos;
 
-					if (!(syntax & RE_NO_BK_BRACES)) {
-						if (c != '\\')
-							FREE_STACK_RETURN(REG_EBRACE);
+		if (val == -2)
+			return -2;
 
-						PATFETCH(c);
-					}
+	  advance:
+		if (!range)
+			break;
+		else if (range > 0) {
+			range--;
+			startpos++;
+		} else {
+			range++;
+			startpos--;
+		}
+	}
+	return -1;
+}								/* re_search_2 */
 
-					if (c != '}') {
-						if (!(syntax & RE_INTERVALS)
-							&& (syntax & RE_NO_BK_BRACES)) goto
-								unfetch_interval;
-						else
-							FREE_STACK_RETURN(REG_BADBR);
-					}
+#ifdef _LIBC
+weak_alias(__re_search_2, re_search_2)
+#endif
+/* This converts PTR, a pointer into one of the search strings `string1'
+   and `string2' into an offset from the beginning of that string.  */
+#define POINTER_TO_OFFSET(ptr)			\
+  (FIRST_STRING_P (ptr)				\
+   ? ((regoff_t) ((ptr) - string1))		\
+   : ((regoff_t) ((ptr) - string2 + size1)))
+/* Macros for dealing with the split strings in re_match_2.  */
+#define MATCHING_IN_FIRST_STRING  (dend == end_match_1)
+/* Call before fetching a character with *d.  This switches over to
+   string2 if necessary.  */
+#define PREFETCH()							\
+  while (d == dend)						    	\
+    {									\
+      /* End of string2 => fail.  */					\
+      if (dend == end_match_2) 						\
+        goto fail;							\
+      /* End of string1 => advance to string2.  */ 			\
+      d = string2;						        \
+      dend = end_match_2;						\
+    }
+/* Test if at very beginning or at very end of the virtual concatenation
+   of `string1' and `string2'.  If only one string, it's `string2'.  */
+#define AT_STRINGS_BEG(d) ((d) == (size1 ? string1 : string2) || !size2)
+#define AT_STRINGS_END(d) ((d) == end2)
+/* Test if D points to a character which is word-constituent.  We have
+   two special cases to check for: if past the end of string1, look at
+   the first character in string2; and if before the beginning of
+   string2, look at the last character in string1.  */
+#define WORDCHAR_P(d)							\
+  (SYNTAX ((d) == end1 ? *string2					\
+           : (d) == string2 - 1 ? *(end1 - 1) : *(d))			\
+   == Sword)
+/* Disabled due to a compiler bug -- see comment at case wordbound */
+#if 0
+/* Test if the character before D and the one at D differ with respect
+   to being word-constituent.  */
+#define AT_WORD_BOUNDARY(d)						\
+  (AT_STRINGS_BEG (d) || AT_STRINGS_END (d)				\
+   || WORDCHAR_P (d - 1) != WORDCHAR_P (d))
+#endif
+/* Free everything we malloc.  */
+#ifdef MATCH_MAY_ALLOCATE
+# define FREE_VAR(var) if (var) REGEX_FREE (var); var = NULL
+# define FREE_VARIABLES()						\
+  do {									\
+    REGEX_FREE_STACK (fail_stack.stack);				\
+    FREE_VAR (regstart);						\
+    FREE_VAR (regend);							\
+    FREE_VAR (old_regstart);						\
+    FREE_VAR (old_regend);						\
+    FREE_VAR (best_regstart);						\
+    FREE_VAR (best_regend);						\
+    FREE_VAR (reg_info);						\
+    FREE_VAR (reg_dummy);						\
+    FREE_VAR (reg_info_dummy);						\
+  } while (0)
+#else
+# define FREE_VARIABLES() ((void)0)	/* Do nothing!  But inhibit gcc warning. */
+#endif							/* not MATCH_MAY_ALLOCATE */
+/* These values must meet several constraints.  They must not be valid
+   register values; since we have a limit of 255 registers (because
+   we use only one byte in the pattern for the register number), we can
+   use numbers larger than 255.  They must differ by 1, because of
+   NUM_FAILURE_ITEMS above.  And the value for the lowest register must
+   be larger than the value for the highest register, so we do not try
+   to actually save any registers when none are active.  */
+#define NO_HIGHEST_ACTIVE_REG (1 << BYTEWIDTH)
+#define NO_LOWEST_ACTIVE_REG (NO_HIGHEST_ACTIVE_REG + 1)
+/* Matching routines.  */
+#ifndef emacs					/* Emacs never uses this.  */
+/* re_match is like re_match_2 except it takes only a single string.  */
+int re_match(bufp, string, size, pos, regs)
+struct re_pattern_buffer *bufp;
+const char *string;
+int size, pos;
+struct re_registers *regs;
+{
+	int result = re_match_2_internal(bufp, NULL, 0, string, size,
+									 pos, regs, size);
 
-					/* We just parsed a valid interval.  */
+# ifndef REGEX_MALLOC
+#  ifdef C_ALLOCA
+	alloca(0);
+#  endif
+# endif
+	return result;
+}
 
-					/* If it's invalid to have no preceding re.  */
-					if (!laststart) {
-						if (syntax & RE_CONTEXT_INVALID_OPS)
-							FREE_STACK_RETURN(REG_BADRPT);
-						else if (syntax & RE_CONTEXT_INDEP_OPS)
-							laststart = b;
-						else
-							goto unfetch_interval;
-					}
+# ifdef _LIBC
+weak_alias(__re_match, re_match)
+# endif
+#endif							/* not emacs */
+static boolean group_match_null_string_p _RE_ARGS((unsigned char **p,
+												   unsigned char *end,
+												   register_info_type *
 
-					/* If the upper bound is zero, don't want to succeed at
-					   all; jump from `laststart' to `b + 3', which will be
-					   the end of the buffer after we insert the jump.  */
-					if (upper_bound == 0) {
-						GET_BUFFER_SPACE(3);
-						INSERT_JUMP(jump, laststart, b + 3);
-						b += 3;
-					}
+												   reg_info));
+static boolean alt_match_null_string_p
+_RE_ARGS(
 
-					/* Otherwise, we have a nontrivial interval.  When
-					   we're all done, the pattern will look like:
-					   set_number_at <jump count> <upper bound>
-					   set_number_at <succeed_n count> <lower bound>
-					   succeed_n <after jump addr> <succeed_n count>
-					   <body of loop>
-					   jump_n <succeed_n addr> <jump count>
-					   (The upper bound and `jump_n' are omitted if
-					   `upper_bound' is 1, though.)  */
-					else {		/* If the upper bound is > 1, we need to insert
-								   more at the end of the loop.  */
-						unsigned nbytes = 10 + (upper_bound > 1) * 10;
+		 (unsigned char *p, unsigned char *end,
+		  register_info_type * reg_info));
+static boolean common_op_match_null_string_p
+_RE_ARGS(
 
-						GET_BUFFER_SPACE(nbytes);
+		 (unsigned char **p, unsigned char *end,
+		  register_info_type * reg_info));
+static int bcmp_translate
+_RE_ARGS((const char *s1, const char *s2, int len, char *translate));
 
-						/* Initialize lower bound of the `succeed_n', even
-						   though it will be set during matching by its
-						   attendant `set_number_at' (inserted next),
-						   because `re_compile_fastmap' needs to know.
-						   Jump to the `jump_n' we might insert below.  */
-						INSERT_JUMP2(succeed_n, laststart,
-									 b + 5 + (upper_bound > 1) * 5,
-									 lower_bound);
-						b += 5;
+/* re_match_2 matches the compiled pattern in BUFP against the
+   the (virtual) concatenation of STRING1 and STRING2 (of length SIZE1
+   and SIZE2, respectively).  We start matching at POS, and stop
+   matching at STOP.
 
-						/* Code to initialize the lower bound.  Insert
-						   before the `succeed_n'.  The `5' is the last two
-						   bytes of this `set_number_at', plus 3 bytes of
-						   the following `succeed_n'.  */
-						insert_op2(set_number_at, laststart, 5,
-								   lower_bound, b);
-						b += 5;
+   If REGS is non-null and the `no_sub' field of BUFP is nonzero, we
+   store offsets for the substring each group matched in REGS.  See the
+   documentation for exactly how many groups we fill.
 
-						if (upper_bound > 1) {	/* More than one repetition is allowed, so
-												   append a backward jump to the `succeed_n'
-												   that starts this interval.
+   We return -1 if no match, -2 if an internal error (such as the
+   failure stack overflowing).  Otherwise, we return the length of the
+   matched substring.  */
 
-												   When we've reached this during matching,
-												   we'll have matched the interval once, so
-												   jump back only `upper_bound - 1' times.  */
-							STORE_JUMP2(jump_n, b, laststart + 5,
-										upper_bound - 1);
-							b += 5;
+int re_match_2(bufp, string1, size1, string2, size2, pos, regs, stop)
+struct re_pattern_buffer *bufp;
+const char *string1, *string2;
+int size1, size2;
+int pos;
+struct re_registers *regs;
+int stop;
+{
+	int result = re_match_2_internal(bufp, string1, size1, string2, size2,
+									 pos, regs, stop);
 
-							/* The location we want to set is the second
-							   parameter of the `jump_n'; that is `b-2' as
-							   an absolute address.  `laststart' will be
-							   the `set_number_at' we're about to insert;
-							   `laststart+3' the number to set, the source
-							   for the relative address.  But we are
-							   inserting into the middle of the pattern --
-							   so everything is getting moved up by 5.
-							   Conclusion: (b - 2) - (laststart + 3) + 5,
-							   i.e., b - laststart.
+#ifndef REGEX_MALLOC
+# ifdef C_ALLOCA
+	alloca(0);
+# endif
+#endif
+	return result;
+}
 
-							   We insert this at the beginning of the loop
-							   so that if we fail during matching, we'll
-							   reinitialize the bounds.  */
-							insert_op2(set_number_at, laststart,
-									   b - laststart, upper_bound - 1, b);
-							b += 5;
-						}
-					}
-					pending_exact = 0;
-					beg_interval = NULL;
-				}
-				break;
+#ifdef _LIBC
+weak_alias(__re_match_2, re_match_2)
+#endif
+/* This is a separate function so that we can force an alloca cleanup
+   afterwards.  */
+static int
+re_match_2_internal(bufp, string1, size1, string2, size2, pos, regs, stop)
+struct re_pattern_buffer *bufp;
+const char *string1, *string2;
+int size1, size2;
+int pos;
+struct re_registers *regs;
+int stop;
+{
+	/* General temporaries.  */
+	int mcnt;
+	unsigned char *p1;
 
-			  unfetch_interval:
-				/* If an invalid interval, match the characters as literals.  */
-				assert(beg_interval);
-				p = beg_interval;
-				beg_interval = NULL;
+	/* Just past the end of the corresponding string.  */
+	const char *end1, *end2;
 
-				/* normal_char and normal_backslash need `c'.  */
-				PATFETCH(c);
+	/* Pointers into string1 and string2, just past the last characters in
+	   each to consider matching.  */
+	const char *end_match_1, *end_match_2;
 
-				if (!(syntax & RE_NO_BK_BRACES)) {
-					if (p > pattern && p[-1] == '\\')
-						goto normal_backslash;
-				}
-				goto normal_char;
+	/* Where we are in the data, and the end of the current string.  */
+	const char *d, *dend;
 
-#ifdef emacs
-				/* There is no way to specify the before_dot and after_dot
-				   operators.  rms says this is ok.  --karl  */
-			case '=':
-				BUF_PUSH(at_dot);
-				break;
+	/* Where we are in the pattern, and the end of the pattern.  */
+	unsigned char *p = bufp->buffer;
+	register unsigned char *pend = p + bufp->used;
 
-			case 's':
-				laststart = b;
-				PATFETCH(c);
-				BUF_PUSH_2(syntaxspec, syntax_spec_code[c]);
-				break;
+	/* Mark the opcode just after a start_memory, so we can test for an
+	   empty subpattern when we get to the stop_memory.  */
+	unsigned char *just_past_start_mem = 0;
 
-			case 'S':
-				laststart = b;
-				PATFETCH(c);
-				BUF_PUSH_2(notsyntaxspec, syntax_spec_code[c]);
-				break;
-#endif							/* emacs */
+	/* We use this to map every character in the string.  */
+	RE_TRANSLATE_TYPE translate = bufp->translate;
 
+	/* Failure point stack.  Each place that can handle a failure further
+	   down the line pushes a failure point on this stack.  It consists of
+	   restart, regend, and reg_info for all registers corresponding to
+	   the subexpressions we're currently inside, plus the number of such
+	   registers, and, finally, two char *'s.  The first char * is where
+	   to resume scanning the pattern; the second one is where to resume
+	   scanning the strings.  If the latter is zero, the failure point is
+	   a ``dummy''; if a failure happens and the failure point is a dummy,
+	   it gets discarded and the next next one is tried.  */
+#ifdef MATCH_MAY_ALLOCATE		/* otherwise, this is global.  */
+	fail_stack_type fail_stack;
+#endif
+#ifdef DEBUG
+	static unsigned failure_id;
+	unsigned nfailure_points_pushed = 0, nfailure_points_popped = 0;
+#endif
 
-			case 'w':
-				if (syntax & RE_NO_GNU_OPS)
-					goto normal_char;
-				laststart = b;
-				BUF_PUSH(wordchar);
-				break;
+#ifdef REL_ALLOC
+	/* This holds the pointer to the failure stack, when
+	   it is allocated relocatably.  */
+	fail_stack_elt_t *failure_stack_ptr;
+#endif
 
+	/* We fill all the registers internally, independent of what we
+	   return, for use in backreferences.  The number here includes
+	   an element for register zero.  */
+	size_t num_regs = bufp->re_nsub + 1;
 
-			case 'W':
-				if (syntax & RE_NO_GNU_OPS)
-					goto normal_char;
-				laststart = b;
-				BUF_PUSH(notwordchar);
-				break;
+	/* The currently active registers.  */
+	active_reg_t lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+	active_reg_t highest_active_reg = NO_HIGHEST_ACTIVE_REG;
 
+	/* Information on the contents of registers. These are pointers into
+	   the input strings; they record just what was matched (on this
+	   attempt) by a subexpression part of the pattern, that is, the
+	   regnum-th regstart pointer points to where in the pattern we began
+	   matching and the regnum-th regend points to right after where we
+	   stopped matching the regnum-th subexpression.  (The zeroth register
+	   keeps track of what the whole pattern matches.)  */
+#ifdef MATCH_MAY_ALLOCATE		/* otherwise, these are global.  */
+	const char **regstart, **regend;
+#endif
 
-			case '<':
-				if (syntax & RE_NO_GNU_OPS)
-					goto normal_char;
-				BUF_PUSH(wordbeg);
-				break;
+	/* If a group that's operated upon by a repetition operator fails to
+	   match anything, then the register for its start will need to be
+	   restored because it will have been set to wherever in the string we
+	   are when we last see its open-group operator.  Similarly for a
+	   register's end.  */
+#ifdef MATCH_MAY_ALLOCATE		/* otherwise, these are global.  */
+	const char **old_regstart, **old_regend;
+#endif
 
-			case '>':
-				if (syntax & RE_NO_GNU_OPS)
-					goto normal_char;
-				BUF_PUSH(wordend);
-				break;
+	/* The is_active field of reg_info helps us keep track of which (possibly
+	   nested) subexpressions we are currently in. The matched_something
+	   field of reg_info[reg_num] helps us tell whether or not we have
+	   matched any of the pattern so far this time through the reg_num-th
+	   subexpression.  These two fields get reset each time through any
+	   loop their register is in.  */
+#ifdef MATCH_MAY_ALLOCATE		/* otherwise, this is global.  */
+	register_info_type *reg_info;
+#endif
 
-			case 'b':
-				if (syntax & RE_NO_GNU_OPS)
-					goto normal_char;
-				BUF_PUSH(wordbound);
-				break;
+	/* The following record the register info as found in the above
+	   variables when we find a match better than any we've seen before.
+	   This happens as we backtrack through the failure points, which in
+	   turn happens only if we have not yet matched the entire string. */
+	unsigned best_regs_set = false;
 
-			case 'B':
-				if (syntax & RE_NO_GNU_OPS)
-					goto normal_char;
-				BUF_PUSH(notwordbound);
-				break;
+#ifdef MATCH_MAY_ALLOCATE		/* otherwise, these are global.  */
+	const char **best_regstart, **best_regend;
+#endif
 
-			case '`':
-				if (syntax & RE_NO_GNU_OPS)
-					goto normal_char;
-				BUF_PUSH(begbuf);
-				break;
+	/* Logically, this is `best_regend[0]'.  But we don't want to have to
+	   allocate space for that if we're not allocating space for anything
+	   else (see below).  Also, we never need info about register 0 for
+	   any of the other register vectors, and it seems rather a kludge to
+	   treat `best_regend' differently than the rest.  So we keep track of
+	   the end of the best match so far in a separate variable.  We
+	   initialize this to NULL so that when we backtrack the first time
+	   and need to test it, it's not garbage.  */
+	const char *match_end = NULL;
 
-			case '\'':
-				if (syntax & RE_NO_GNU_OPS)
-					goto normal_char;
-				BUF_PUSH(endbuf);
-				break;
+	/* This helps SET_REGS_MATCHED avoid doing redundant work.  */
+	int set_regs_matched_done = 0;
 
-			case '1':
-			case '2':
-			case '3':
-			case '4':
-			case '5':
-			case '6':
-			case '7':
-			case '8':
-			case '9':
-				if (syntax & RE_NO_BK_REFS)
-					goto normal_char;
+	/* Used when we pop values we don't care about.  */
+#ifdef MATCH_MAY_ALLOCATE		/* otherwise, these are global.  */
+	const char **reg_dummy;
+	register_info_type *reg_info_dummy;
+#endif
 
-				c1 = c - '0';
+#ifdef DEBUG
+	/* Counts the total number of registers pushed.  */
+	unsigned num_regs_pushed = 0;
+#endif
 
-				if (c1 > regnum)
-					FREE_STACK_RETURN(REG_ESUBREG);
+	DEBUG_PRINT1("\n\nEntering re_match_2.\n");
 
-				/* Can't back reference to a subexpression if inside of it.  */
-				if (group_in_compile_stack(compile_stack, (regnum_t) c1))
-					goto normal_char;
+	INIT_FAIL_STACK();
 
-				laststart = b;
-				BUF_PUSH_2(duplicate, c1);
-				break;
+#ifdef MATCH_MAY_ALLOCATE
+	/* Do not bother to initialize all the register variables if there are
+	   no groups in the pattern, as it takes a fair amount of time.  If
+	   there are groups, we include space for register 0 (the whole
+	   pattern), even though we never use it, since it simplifies the
+	   array indexing.  We should fix this.  */
+	if (bufp->re_nsub) {
+		regstart = REGEX_TALLOC(num_regs, const char *);
+		regend = REGEX_TALLOC(num_regs, const char *);
+		old_regstart = REGEX_TALLOC(num_regs, const char *);
+		old_regend = REGEX_TALLOC(num_regs, const char *);
+		best_regstart = REGEX_TALLOC(num_regs, const char *);
+		best_regend = REGEX_TALLOC(num_regs, const char *);
 
+		reg_info = REGEX_TALLOC(num_regs, register_info_type);
+		reg_dummy = REGEX_TALLOC(num_regs, const char *);
 
-			case '+':
-			case '?':
-				if (syntax & RE_BK_PLUS_QM)
-					goto handle_plus;
-				else
-					goto normal_backslash;
+		reg_info_dummy = REGEX_TALLOC(num_regs, register_info_type);
 
-			default:
-			  normal_backslash:
-				/* You might think it would be useful for \ to mean
-				   not to translate; but if we don't translate it
-				   it will never match anything.  */
-				c = TRANSLATE(c);
-				goto normal_char;
-			}
-			break;
+		if (!(regstart && regend && old_regstart && old_regend && reg_info
+			  && best_regstart && best_regend && reg_dummy
+			  && reg_info_dummy)) {
+			FREE_VARIABLES();
+			return -2;
+		}
+	} else {
+		/* We must initialize all our variables to NULL, so that
+		   `FREE_VARIABLES' doesn't try to free them.  */
+		regstart = regend = old_regstart = old_regend = best_regstart
+			= best_regend = reg_dummy = NULL;
+		reg_info = reg_info_dummy = (register_info_type *) NULL;
+	}
+#endif							/* MATCH_MAY_ALLOCATE */
 
+	/* The starting position is bogus.  */
+	if (pos < 0 || pos > size1 + size2) {
+		FREE_VARIABLES();
+		return -1;
+	}
 
-		default:
-			/* Expects the character in `c'.  */
-		  normal_char:
-			/* If no exactn currently being built.  */
-			if (!pending_exact
-				/* If last exactn not at current position.  */
-				|| pending_exact + *pending_exact + 1 != b
-				/* We have only one byte following the exactn for the count.  */
-				|| *pending_exact == (1 << BYTEWIDTH) - 1
-				/* If followed by a repetition operator.  */
-				|| *p == '*' || *p == '^' || ((syntax & RE_BK_PLUS_QM)
-											  ? *p == '\\' && (p[1] == '+'
-															   || p[1] ==
-															   '?') : (*p
-																	   ==
-																	   '+'
-																	   ||
-																	   *p
-																	   ==
-																	   '?'))
-				|| ((syntax & RE_INTERVALS)
-					&& ((syntax & RE_NO_BK_BRACES)
-						? *p == '{' : (p[0] == '\\' && p[1] == '{')))) {
-				/* Start building a new exactn.  */
+	/* Initialize subexpression text positions to -1 to mark ones that no
+	   start_memory/stop_memory has been seen for. Also initialize the
+	   register information struct.  */
+	for (mcnt = 1; (unsigned) mcnt < num_regs; mcnt++) {
+		regstart[mcnt] = regend[mcnt]
+			= old_regstart[mcnt] = old_regend[mcnt] = REG_UNSET_VALUE;
 
-				laststart = b;
+		REG_MATCH_NULL_STRING_P(reg_info[mcnt]) = MATCH_NULL_UNSET_VALUE;
+		IS_ACTIVE(reg_info[mcnt]) = 0;
+		MATCHED_SOMETHING(reg_info[mcnt]) = 0;
+		EVER_MATCHED_SOMETHING(reg_info[mcnt]) = 0;
+	}
 
-				BUF_PUSH_2(exactn, 0);
-				pending_exact = b - 1;
-			}
+	/* We move `string1' into `string2' if the latter's empty -- but not if
+	   `string1' is null.  */
+	if (size2 == 0 && string1 != NULL) {
+		string2 = string1;
+		size2 = size1;
+		string1 = 0;
+		size1 = 0;
+	}
+	end1 = string1 + size1;
+	end2 = string2 + size2;
 
-			BUF_PUSH(c);
-			(*pending_exact)++;
-			break;
-		}						/* switch (c) */
-	}							/* while p != pend */
+	/* Compute where to stop matching, within the two strings.  */
+	if (stop <= size1) {
+		end_match_1 = string1 + stop;
+		end_match_2 = string2;
+	} else {
+		end_match_1 = end1;
+		end_match_2 = string2 + stop - size1;
+	}
 
+	/* `p' scans through the pattern as `d' scans through the data.
+	   `dend' is the end of the input string that `d' points within.  `d'
+	   is advanced into the following input string whenever necessary, but
+	   this happens before fetching; therefore, at the beginning of the
+	   loop, `d' can be pointing at the end of a string, but it cannot
+	   equal `string2'.  */
+	if (size1 > 0 && pos <= size1) {
+		d = string1 + pos;
+		dend = end_match_1;
+	} else {
+		d = string2 + pos - size1;
+		dend = end_match_2;
+	}
 
-	/* Through the pattern now.  */
+	DEBUG_PRINT1("The compiled pattern is:\n");
+	DEBUG_PRINT_COMPILED_PATTERN(bufp, p, pend);
+	DEBUG_PRINT1("The string to match is: `");
+	DEBUG_PRINT_DOUBLE_STRING(d, string1, size1, string2, size2);
+	DEBUG_PRINT1("'\n");
 
-	if (fixup_alt_jump)
-		STORE_JUMP(jump_past_alt, fixup_alt_jump, b);
+	/* This loops over pattern commands.  It exits by returning from the
+	   function if the match is complete, or it drops through if the match
+	   fails at this starting point in the input data.  */
+	for (;;) {
+#ifdef _LIBC
+		DEBUG_PRINT2("\n%p: ", p);
+#else
+		DEBUG_PRINT2("\n0x%x: ", p);
+#endif
 
-	if (!COMPILE_STACK_EMPTY)
-		FREE_STACK_RETURN(REG_EPAREN);
+		if (p == pend) {		/* End of pattern means we might have succeeded.  */
+			DEBUG_PRINT1("end of pattern ... ");
 
-	/* If we don't want backtracking, force success
-	   the first time we reach the end of the compiled pattern.  */
-	if (syntax & RE_NO_POSIX_BACKTRACKING)
-		BUF_PUSH(succeed);
+			/* If we haven't matched the entire string, and we want the
+			   longest match, try backtracking.  */
+			if (d != end_match_2) {
+				/* 1 if this match ends in the same string (string1 or string2)
+				   as the best previous match.  */
+				boolean same_str_p = (FIRST_STRING_P(match_end)
+									  == MATCHING_IN_FIRST_STRING);
 
-	free(compile_stack.stack);
+				/* 1 if this match is the best seen so far.  */
+				boolean best_match_p;
 
-	/* We have succeeded; set the length of the buffer.  */
-	bufp->used = b - bufp->buffer;
+				/* AIX compiler got confused when this was combined
+				   with the previous declaration.  */
+				if (same_str_p)
+					best_match_p = d > match_end;
+				else
+					best_match_p = !MATCHING_IN_FIRST_STRING;
 
-#ifdef DEBUG
-	if (debug) {
-		DEBUG_PRINT1("\nCompiled pattern: \n");
-		print_compiled_pattern(bufp);
-	}
-#endif							/* DEBUG */
+				DEBUG_PRINT1("backtracking.\n");
 
-#ifndef MATCH_MAY_ALLOCATE
-	/* Initialize the failure stack to the largest possible stack.  This
-	   isn't necessary unless we're trying to avoid calling alloca in
-	   the search and match routines.  */
-	{
-		int num_regs = bufp->re_nsub + 1;
+				if (!FAIL_STACK_EMPTY()) {	/* More failure points to try.  */
 
-		/* Since DOUBLE_FAIL_STACK refuses to double only if the current size
-		   is strictly greater than re_max_failures, the largest possible stack
-		   is 2 * re_max_failures failure points.  */
-		if (fail_stack.size < (2 * re_max_failures * MAX_FAILURE_ITEMS)) {
-			fail_stack.size = (2 * re_max_failures * MAX_FAILURE_ITEMS);
+					/* If exceeds best match so far, save it.  */
+					if (!best_regs_set || best_match_p) {
+						best_regs_set = true;
+						match_end = d;
 
-# ifdef emacs
-			if (!fail_stack.stack)
-				fail_stack.stack
-					= (fail_stack_elt_t *) xmalloc(fail_stack.size
-												   *
-												   sizeof
-												   (fail_stack_elt_t));
-			else
-				fail_stack.stack =
-					(fail_stack_elt_t *) xrealloc(fail_stack.stack,
-												  (fail_stack.size *
-												   sizeof
-												   (fail_stack_elt_t)));
-# else							/* not emacs */
-			if (!fail_stack.stack)
-				fail_stack.stack
-					= (fail_stack_elt_t *) malloc(fail_stack.size
-												  *
-												  sizeof
-												  (fail_stack_elt_t));
-			else
-				fail_stack.stack =
-					(fail_stack_elt_t *) realloc(fail_stack.stack,
-												 (fail_stack.size *
-												  sizeof
-												  (fail_stack_elt_t)));
-# endif							/* not emacs */
-		}
+						DEBUG_PRINT1("\nSAVING match as best so far.\n");
 
-		regex_grow_registers(num_regs);
-	}
-#endif							/* not MATCH_MAY_ALLOCATE */
+						for (mcnt = 1; (unsigned) mcnt < num_regs; mcnt++) {
+							best_regstart[mcnt] = regstart[mcnt];
+							best_regend[mcnt] = regend[mcnt];
+						}
+					}
+					goto fail;
+				}
 
-	return REG_NOERROR;
-}								/* regex_compile */
-
-/* Subroutines for `regex_compile'.  */
+				/* If no failure points, don't restore garbage.  And if
+				   last match is real best match, don't restore second
+				   best one. */
+				else if (best_regs_set && !best_match_p) {
+				  restore_best_regs:
+					/* Restore best match.  It may happen that `dend ==
+					   end_match_1' while the restored d is in string2.
+					   For example, the pattern `x.*y.*z' against the
+					   strings `x-' and `y-z-', if the two strings are
+					   not consecutive in memory.  */
+					DEBUG_PRINT1("Restoring best registers.\n");
 
-/* Store OP at LOC followed by two-byte integer parameter ARG.  */
+					d = match_end;
+					dend = ((d >= string1 && d <= end1)
+							? end_match_1 : end_match_2);
 
-static void store_op1(op, loc, arg)
-re_opcode_t op;
-unsigned char *loc;
-int arg;
-{
-	*loc = (unsigned char) op;
-	STORE_NUMBER(loc + 1, arg);
-}
+					for (mcnt = 1; (unsigned) mcnt < num_regs; mcnt++) {
+						regstart[mcnt] = best_regstart[mcnt];
+						regend[mcnt] = best_regend[mcnt];
+					}
+				}
+			}
+			/* d != end_match_2 */
+		  succeed_label:
+			DEBUG_PRINT1("Accepting match.\n");
 
+			/* If caller wants register contents data back, do it.  */
+			if (regs && !bufp->no_sub) {
+				/* Have the register data arrays been allocated?  */
+				if (bufp->regs_allocated == REGS_UNALLOCATED) {	/* No.  So allocate them with malloc.  We need one
+																   extra element beyond `num_regs' for the `-1' marker
+																   GNU code uses.  */
+					regs->num_regs = MAX(RE_NREGS, num_regs + 1);
+					regs->start = TALLOC(regs->num_regs, regoff_t);
+					regs->end = TALLOC(regs->num_regs, regoff_t);
+					if (regs->start == NULL || regs->end == NULL) {
+						FREE_VARIABLES();
+						return -2;
+					}
+					bufp->regs_allocated = REGS_REALLOCATE;
+				} else if (bufp->regs_allocated == REGS_REALLOCATE) {	/* Yes.  If we need more elements than were already
+																		   allocated, reallocate them.  If we need fewer, just
+																		   leave it alone.  */
+					if (regs->num_regs < num_regs + 1) {
+						regs->num_regs = num_regs + 1;
+						RETALLOC(regs->start, regs->num_regs, regoff_t);
+						RETALLOC(regs->end, regs->num_regs, regoff_t);
+						if (regs->start == NULL || regs->end == NULL) {
+							FREE_VARIABLES();
+							return -2;
+						}
+					}
+				} else {
+					/* These braces fend off a "empty body in an else-statement"
+					   warning under GCC when assert expands to nothing.  */
+					assert(bufp->regs_allocated == REGS_FIXED);
+				}
 
-/* Like `store_op1', but for two two-byte parameters ARG1 and ARG2.  */
+				/* Convert the pointer data in `regstart' and `regend' to
+				   indices.  Register zero has to be set differently,
+				   since we haven't kept track of any info for it.  */
+				if (regs->num_regs > 0) {
+					regs->start[0] = pos;
+					regs->end[0] = (MATCHING_IN_FIRST_STRING
+									? ((regoff_t) (d - string1))
+									: ((regoff_t) (d - string2 + size1)));
+				}
 
-static void store_op2(op, loc, arg1, arg2)
-re_opcode_t op;
-unsigned char *loc;
-int arg1, arg2;
-{
-	*loc = (unsigned char) op;
-	STORE_NUMBER(loc + 1, arg1);
-	STORE_NUMBER(loc + 3, arg2);
-}
+				/* Go through the first `min (num_regs, regs->num_regs)'
+				   registers, since that is all we initialized.  */
+				for (mcnt = 1;
+					 (unsigned) mcnt < MIN(num_regs, regs->num_regs);
+					 mcnt++) {
+					if (REG_UNSET(regstart[mcnt])
+						|| REG_UNSET(regend[mcnt])) regs->start[mcnt] =
+							regs->end[mcnt] = -1;
+					else {
+						regs->start[mcnt]
+							= (regoff_t) POINTER_TO_OFFSET(regstart[mcnt]);
+						regs->end[mcnt]
+							= (regoff_t) POINTER_TO_OFFSET(regend[mcnt]);
+					}
+				}
 
+				/* If the regs structure we return has more elements than
+				   were in the pattern, set the extra elements to -1.  If
+				   we (re)allocated the registers, this is the case,
+				   because we always allocate enough to have at least one
+				   -1 at the end.  */
+				for (mcnt = num_regs; (unsigned) mcnt < regs->num_regs;
+					 mcnt++)
+					regs->start[mcnt] = regs->end[mcnt] = -1;
+			}
+			/* regs && !bufp->no_sub */
+			DEBUG_PRINT4
+				("%u failure points pushed, %u popped (%u remain).\n",
+				 nfailure_points_pushed, nfailure_points_popped,
+				 nfailure_points_pushed - nfailure_points_popped);
+			DEBUG_PRINT2("%u registers pushed.\n", num_regs_pushed);
 
-/* Copy the bytes from LOC to END to open up three bytes of space at LOC
-   for OP followed by two-byte integer parameter ARG.  */
+			mcnt = d - pos - (MATCHING_IN_FIRST_STRING
+							  ? string1 : string2 - size1);
 
-static void insert_op1(op, loc, arg, end)
-re_opcode_t op;
-unsigned char *loc;
-int arg;
-unsigned char *end;
-{
-	register unsigned char *pfrom = end;
-	register unsigned char *pto = end + 3;
+			DEBUG_PRINT2("Returning %d from re_match_2.\n", mcnt);
 
-	while (pfrom != loc)
-		*--pto = *--pfrom;
+			FREE_VARIABLES();
+			return mcnt;
+		}
 
-	store_op1(op, loc, arg);
-}
+		/* Otherwise match next pattern command.  */
+		switch (SWITCH_ENUM_CAST((re_opcode_t) * p++)) {
+			/* Ignore these.  Used to ignore the n of succeed_n's which
+			   currently have n == 0.  */
+		case no_op:
+			DEBUG_PRINT1("EXECUTING no_op.\n");
+			break;
 
+		case succeed:
+			DEBUG_PRINT1("EXECUTING succeed.\n");
+			goto succeed_label;
 
-/* Like `insert_op1', but for two two-byte parameters ARG1 and ARG2.  */
+			/* Match the next n pattern characters exactly.  The following
+			   byte in the pattern defines n, and the n bytes after that
+			   are the characters to match.  */
+		case exactn:
+			mcnt = *p++;
+			DEBUG_PRINT2("EXECUTING exactn %d.\n", mcnt);
 
-static void insert_op2(op, loc, arg1, arg2, end)
-re_opcode_t op;
-unsigned char *loc;
-int arg1, arg2;
-unsigned char *end;
-{
-	register unsigned char *pfrom = end;
-	register unsigned char *pto = end + 5;
+			/* This is written out as an if-else so we don't waste time
+			   testing `translate' inside the loop.  */
+			if (translate) {
+				do {
+					PREFETCH();
+					if ((unsigned char) translate[(unsigned char) *d++]
+						!= (unsigned char) *p++)
+						goto fail;
+				}
+				while (--mcnt);
+			} else {
+				do {
+					PREFETCH();
+					if (*d++ != (char) *p++)
+						goto fail;
+				}
+				while (--mcnt);
+			}
+			SET_REGS_MATCHED();
+			break;
 
-	while (pfrom != loc)
-		*--pto = *--pfrom;
 
-	store_op2(op, loc, arg1, arg2);
-}
+			/* Match any character except possibly a newline or a null.  */
+		case anychar:
+			DEBUG_PRINT1("EXECUTING anychar.\n");
 
+			PREFETCH();
 
-/* P points to just after a ^ in PATTERN.  Return true if that ^ comes
-   after an alternative or a begin-subexpression.  We assume there is at
-   least one character before the ^.  */
+			if ((!(bufp->syntax & RE_DOT_NEWLINE) && TRANSLATE(*d) == '\n')
+				|| (bufp->syntax & RE_DOT_NOT_NULL
+					&& TRANSLATE(*d) == '\000')) goto fail;
 
-static boolean at_begline_loc_p(pattern, p, syntax)
-const char *pattern, *p;
-reg_syntax_t syntax;
-{
-	const char *prev = p - 2;
-	boolean prev_prev_backslash = prev > pattern && prev[-1] == '\\';
+			SET_REGS_MATCHED();
+			DEBUG_PRINT2("  Matched `%d'.\n", *d);
+			d++;
+			break;
 
-	return
-		/* After a subexpression?  */
-		(*prev == '(' && (syntax & RE_NO_BK_PARENS || prev_prev_backslash))
-		/* After an alternative?  */
-		|| (*prev == '|'
-			&& (syntax & RE_NO_BK_VBAR || prev_prev_backslash));
-}
 
+		case charset:
+		case charset_not:
+		{
+			register unsigned char c;
+			boolean not = (re_opcode_t) * (p - 1) == charset_not;
+
+			DEBUG_PRINT2("EXECUTING charset%s.\n", not ? "_not" : "");
 
-/* The dual of at_begline_loc_p.  This one is for $.  We assume there is
-   at least one character after the $, i.e., `P < PEND'.  */
+			PREFETCH();
+			c = TRANSLATE(*d);	/* The character to match.  */
 
-static boolean at_endline_loc_p(p, pend, syntax)
-const char *p, *pend;
-reg_syntax_t syntax;
-{
-	const char *next = p;
-	boolean next_backslash = *next == '\\';
-	const char *next_next = p + 1 < pend ? p + 1 : 0;
+			/* Cast to `unsigned' instead of `unsigned char' in case the
+			   bit list is a full 32 bytes long.  */
+			if (c < (unsigned) (*p * BYTEWIDTH)
+				&& p[1 + c / BYTEWIDTH] & (1 << (c % BYTEWIDTH)))
+				not = !not;
 
-	return
-		/* Before a subexpression?  */
-		(syntax & RE_NO_BK_PARENS ? *next == ')'
-		 : next_backslash && next_next && *next_next == ')')
-		/* Before an alternative?  */
-		|| (syntax & RE_NO_BK_VBAR ? *next == '|'
-			: next_backslash && next_next && *next_next == '|');
-}
+			p += 1 + *p;
 
+			if (!not)
+				goto fail;
 
-/* Returns true if REGNUM is in one of COMPILE_STACK's elements and
-   false if it's not.  */
+			SET_REGS_MATCHED();
+			d++;
+			break;
+		}
 
-static boolean group_in_compile_stack(compile_stack, regnum)
-compile_stack_type compile_stack;
-regnum_t regnum;
-{
-	int this_element;
 
-	for (this_element = compile_stack.avail - 1;
-		 this_element >= 0; this_element--)
-		if (compile_stack.stack[this_element].regnum == regnum)
-			return true;
+			/* The beginning of a group is represented by start_memory.
+			   The arguments are the register number in the next byte, and the
+			   number of groups inner to this one in the next.  The text
+			   matched within the group is recorded (in the internal
+			   registers data structure) under the register number.  */
+		case start_memory:
+			DEBUG_PRINT3("EXECUTING start_memory %d (%d):\n", *p, p[1]);
 
-	return false;
-}
+			/* Find out if this group can match the empty string.  */
+			p1 = p;				/* To send to group_match_null_string_p.  */
 
+			if (REG_MATCH_NULL_STRING_P(reg_info[*p]) ==
+				MATCH_NULL_UNSET_VALUE)
+					REG_MATCH_NULL_STRING_P(reg_info[*p]) =
+					group_match_null_string_p(&p1, pend, reg_info);
 
-/* Read the ending character of a range (in a bracket expression) from the
-   uncompiled pattern *P_PTR (which ends at PEND).  We assume the
-   starting character is in `P[-2]'.  (`P[-1]' is the character `-'.)
-   Then we set the translation of all bits between the starting and
-   ending characters (inclusive) in the compiled pattern B.
+			/* Save the position in the string where we were the last time
+			   we were at this open-group operator in case the group is
+			   operated upon by a repetition operator, e.g., with `(a*)*b'
+			   against `ab'; then we want to ignore where we are now in
+			   the string in case this attempt to match fails.  */
+			old_regstart[*p] = REG_MATCH_NULL_STRING_P(reg_info[*p])
+				? REG_UNSET(regstart[*p]) ? d : regstart[*p]
+				: regstart[*p];
+			DEBUG_PRINT2("  old_regstart: %d\n",
+						 POINTER_TO_OFFSET(old_regstart[*p]));
 
-   Return an error code.
+			regstart[*p] = d;
+			DEBUG_PRINT2("  regstart: %d\n",
+						 POINTER_TO_OFFSET(regstart[*p]));
 
-   We use these short variable names so we can use the same macros as
-   `regex_compile' itself.  */
+			IS_ACTIVE(reg_info[*p]) = 1;
+			MATCHED_SOMETHING(reg_info[*p]) = 0;
 
-static reg_errcode_t compile_range(p_ptr, pend, translate, syntax, b)
-const char **p_ptr, *pend;
-RE_TRANSLATE_TYPE translate;
-reg_syntax_t syntax;
-unsigned char *b;
-{
-	unsigned this_char;
+			/* Clear this whenever we change the register activity status.  */
+			set_regs_matched_done = 0;
 
-	const char *p = *p_ptr;
-	reg_errcode_t ret;
-	char range_start[2];
-	char range_end[2];
-	char ch[2];
+			/* This is the new highest active register.  */
+			highest_active_reg = *p;
 
-	if (p == pend)
-		return REG_ERANGE;
+			/* If nothing was active before, this is the new lowest active
+			   register.  */
+			if (lowest_active_reg == NO_LOWEST_ACTIVE_REG)
+				lowest_active_reg = *p;
 
-	/* Fetch the endpoints without translating them; the
-	   appropriate translation is done in the bit-setting loop below.  */
-	range_start[0] = p[-2];
-	range_start[1] = '\0';
-	range_end[0] = p[0];
-	range_end[1] = '\0';
+			/* Move past the register number and inner group count.  */
+			p += 2;
+			just_past_start_mem = p;
 
-	/* Have to increment the pointer into the pattern string, so the
-	   caller isn't still at the ending character.  */
-	(*p_ptr)++;
+			break;
 
-	/* Report an error if the range is empty and the syntax prohibits this.  */
-	ret = syntax & RE_NO_EMPTY_RANGES ? REG_ERANGE : REG_NOERROR;
 
-	/* Here we see why `this_char' has to be larger than an `unsigned
-	   char' -- we would otherwise go into an infinite loop, since all
-	   characters <= 0xff.  */
-	ch[1] = '\0';
-	for (this_char = 0; this_char <= (unsigned char) -1; ++this_char) {
-		ch[0] = this_char;
-		if (strcoll(range_start, ch) <= 0 && strcoll(ch, range_end) <= 0) {
-			SET_LIST_BIT(TRANSLATE(this_char));
-			ret = REG_NOERROR;
-		}
-	}
+			/* The stop_memory opcode represents the end of a group.  Its
+			   arguments are the same as start_memory's: the register
+			   number, and the number of inner groups.  */
+		case stop_memory:
+			DEBUG_PRINT3("EXECUTING stop_memory %d (%d):\n", *p, p[1]);
 
-	return ret;
-}
-
-/* re_compile_fastmap computes a ``fastmap'' for the compiled pattern in
-   BUFP.  A fastmap records which of the (1 << BYTEWIDTH) possible
-   characters can start a string that matches the pattern.  This fastmap
-   is used by re_search to skip quickly over impossible starting points.
+			/* We need to save the string position the last time we were at
+			   this close-group operator in case the group is operated
+			   upon by a repetition operator, e.g., with `((a*)*(b*)*)*'
+			   against `aba'; then we want to ignore where we are now in
+			   the string in case this attempt to match fails.  */
+			old_regend[*p] = REG_MATCH_NULL_STRING_P(reg_info[*p])
+				? REG_UNSET(regend[*p]) ? d : regend[*p]
+				: regend[*p];
+			DEBUG_PRINT2("      old_regend: %d\n",
+						 POINTER_TO_OFFSET(old_regend[*p]));
 
-   The caller must supply the address of a (1 << BYTEWIDTH)-byte data
-   area as BUFP->fastmap.
+			regend[*p] = d;
+			DEBUG_PRINT2("      regend: %d\n",
+						 POINTER_TO_OFFSET(regend[*p]));
 
-   We set the `fastmap', `fastmap_accurate', and `can_be_null' fields in
-   the pattern buffer.
+			/* This register isn't active anymore.  */
+			IS_ACTIVE(reg_info[*p]) = 0;
 
-   Returns 0 if we succeed, -2 if an internal error.   */
+			/* Clear this whenever we change the register activity status.  */
+			set_regs_matched_done = 0;
 
-int re_compile_fastmap(bufp)
-struct re_pattern_buffer *bufp;
-{
-	int j, k;
+			/* If this was the only register active, nothing is active
+			   anymore.  */
+			if (lowest_active_reg == highest_active_reg) {
+				lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+				highest_active_reg = NO_HIGHEST_ACTIVE_REG;
+			} else {			/* We must scan for the new highest active register, since
+								   it isn't necessarily one less than now: consider
+								   (a(b)c(d(e)f)g).  When group 3 ends, after the f), the
+								   new highest active register is 1.  */
+				unsigned char r = *p - 1;
 
-#ifdef MATCH_MAY_ALLOCATE
-	fail_stack_type fail_stack;
-#endif
-#ifndef REGEX_MALLOC
-	char *destination;
-#endif
+				while (r > 0 && !IS_ACTIVE(reg_info[r]))
+					r--;
 
-	register char *fastmap = bufp->fastmap;
-	unsigned char *pattern = bufp->buffer;
-	unsigned char *p = pattern;
-	register unsigned char *pend = pattern + bufp->used;
+				/* If we end up at register zero, that means that we saved
+				   the registers as the result of an `on_failure_jump', not
+				   a `start_memory', and we jumped to past the innermost
+				   `stop_memory'.  For example, in ((.)*) we save
+				   registers 1 and 2 as a result of the *, but when we pop
+				   back to the second ), we are at the stop_memory 1.
+				   Thus, nothing is active.  */
+				if (r == 0) {
+					lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+					highest_active_reg = NO_HIGHEST_ACTIVE_REG;
+				} else
+					highest_active_reg = r;
+			}
 
-#ifdef REL_ALLOC
-	/* This holds the pointer to the failure stack, when
-	   it is allocated relocatably.  */
-	fail_stack_elt_t *failure_stack_ptr;
-#endif
+			/* If just failed to match something this time around with a
+			   group that's operated on by a repetition operator, try to
+			   force exit from the ``loop'', and restore the register
+			   information for this group that we had before trying this
+			   last match.  */
+			if ((!MATCHED_SOMETHING(reg_info[*p])
+				 || just_past_start_mem == p - 1)
+				&& (p + 2) < pend) {
+				boolean is_a_jump_n = false;
 
-	/* Assume that each path through the pattern can be null until
-	   proven otherwise.  We set this false at the bottom of switch
-	   statement, to which we get only if a particular path doesn't
-	   match the empty string.  */
-	boolean path_can_be_null = true;
+				p1 = p + 2;
+				mcnt = 0;
+				switch ((re_opcode_t) * p1++) {
+				case jump_n:
+					is_a_jump_n = true;
+				case pop_failure_jump:
+				case maybe_pop_jump:
+				case jump:
+				case dummy_failure_jump:
+					EXTRACT_NUMBER_AND_INCR(mcnt, p1);
+					if (is_a_jump_n)
+						p1 += 2;
+					break;
+
+				default:
+					/* do nothing */ ;
+				}
+				p1 += mcnt;
+
+				/* If the next operation is a jump backwards in the pattern
+				   to an on_failure_jump right before the start_memory
+				   corresponding to this stop_memory, exit from the loop
+				   by forcing a failure after pushing on the stack the
+				   on_failure_jump's jump in the pattern, and d.  */
+				if (mcnt < 0 && (re_opcode_t) * p1 == on_failure_jump
+					&& (re_opcode_t) p1[3] == start_memory && p1[4] == *p) {
+					/* If this group ever matched anything, then restore
+					   what its registers were before trying this last
+					   failed match, e.g., with `(a*)*b' against `ab' for
+					   regstart[1], and, e.g., with `((a*)*(b*)*)*'
+					   against `aba' for regend[3].
+
+					   Also restore the registers for inner groups for,
+					   e.g., `((a*)(b*))*' against `aba' (register 3 would
+					   otherwise get trashed).  */
 
-	/* We aren't doing a `succeed_n' to begin with.  */
-	boolean succeed_n_p = false;
+					if (EVER_MATCHED_SOMETHING(reg_info[*p])) {
+						unsigned r;
 
-	assert(fastmap != NULL && p != NULL);
+						EVER_MATCHED_SOMETHING(reg_info[*p]) = 0;
 
-	INIT_FAIL_STACK();
-	bzero(fastmap, 1 << BYTEWIDTH);	/* Assume nothing's valid.  */
-	bufp->fastmap_accurate = 1;	/* It will be when we're done.  */
-	bufp->can_be_null = 0;
+						/* Restore this and inner groups' (if any) registers.  */
+						for (r = *p;
+							 r < (unsigned) *p + (unsigned) *(p + 1); r++) {
+							regstart[r] = old_regstart[r];
 
-	while (1) {
-		if (p == pend || *p == succeed) {
-			/* We have reached the (effective) end of pattern.  */
-			if (!FAIL_STACK_EMPTY()) {
-				bufp->can_be_null |= path_can_be_null;
+							/* xx why this test?  */
+							if (old_regend[r] >= regstart[r])
+								regend[r] = old_regend[r];
+						}
+					}
+					p1++;
+					EXTRACT_NUMBER_AND_INCR(mcnt, p1);
+					PUSH_FAILURE_POINT(p1 + mcnt, d, -2);
 
-				/* Reset for next path.  */
-				path_can_be_null = true;
+					goto fail;
+				}
+			}
 
-				p = fail_stack.stack[--fail_stack.avail].pointer;
+			/* Move past the register number and the inner group count.  */
+			p += 2;
+			break;
 
-				continue;
-			} else
-				break;
-		}
 
-		/* We should never be about to go beyond the end of the pattern.  */
-		assert(p < pend);
+			/* \<digit> has been turned into a `duplicate' command which is
+			   followed by the numeric value of <digit> as the register number.  */
+		case duplicate:
+		{
+			register const char *d2, *dend2;
+			int regno = *p++;	/* Get which register to match against.  */
 
-		switch (SWITCH_ENUM_CAST((re_opcode_t) * p++)) {
+			DEBUG_PRINT2("EXECUTING duplicate %d.\n", regno);
 
-			/* I guess the idea here is to simply not bother with a fastmap
-			   if a backreference is used, since it's too hard to figure out
-			   the fastmap for the corresponding group.  Setting
-			   `can_be_null' stops `re_search_2' from using the fastmap, so
-			   that is all we do.  */
-		case duplicate:
-			bufp->can_be_null = 1;
-			goto done;
+			/* Can't back reference a group which we've never matched.  */
+			if (REG_UNSET(regstart[regno]) || REG_UNSET(regend[regno]))
+				goto fail;
 
+			/* Where in input to try to start matching.  */
+			d2 = regstart[regno];
 
-			/* Following are the cases which match a character.  These end
-			   with `break'.  */
+			/* Where to stop matching; if both the place to start and
+			   the place to stop matching are in the same string, then
+			   set to the place to stop, otherwise, for now have to use
+			   the end of the first string.  */
 
-		case exactn:
-			fastmap[p[1]] = 1;
-			break;
+			dend2 = ((FIRST_STRING_P(regstart[regno])
+					  == FIRST_STRING_P(regend[regno]))
+					 ? regend[regno] : end_match_1);
+			for (;;) {
+				/* If necessary, advance to next segment in register
+				   contents.  */
+				while (d2 == dend2) {
+					if (dend2 == end_match_2)
+						break;
+					if (dend2 == regend[regno])
+						break;
 
+					/* End of string1 => advance to string2. */
+					d2 = string2;
+					dend2 = regend[regno];
+				}
+				/* At end of register contents => success */
+				if (d2 == dend2)
+					break;
 
-		case charset:
-			for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
-				if (p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH)))
-					fastmap[j] = 1;
-			break;
+				/* If necessary, advance to next segment in data.  */
+				PREFETCH();
 
+				/* How many characters left in this segment to match.  */
+				mcnt = dend - d;
 
-		case charset_not:
-			/* Chars beyond end of map must be allowed.  */
-			for (j = *p * BYTEWIDTH; j < (1 << BYTEWIDTH); j++)
-				fastmap[j] = 1;
+				/* Want how many consecutive characters we can match in
+				   one shot, so, if necessary, adjust the count.  */
+				if (mcnt > dend2 - d2)
+					mcnt = dend2 - d2;
 
-			for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
-				if (!(p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH))))
-					fastmap[j] = 1;
+				/* Compare that many; failure if mismatch, else move
+				   past them.  */
+				if (translate ? bcmp_translate(d, d2, mcnt, translate)
+					: memcmp(d, d2, mcnt))
+					goto fail;
+				d += mcnt, d2 += mcnt;
+
+				/* Do this because we've match some characters.  */
+				SET_REGS_MATCHED();
+			}
+		}
 			break;
 
 
-		case wordchar:
-			for (j = 0; j < (1 << BYTEWIDTH); j++)
-				if (SYNTAX(j) == Sword)
-					fastmap[j] = 1;
-			break;
+			/* begline matches the empty string at the beginning of the string
+			   (unless `not_bol' is set in `bufp'), and, if
+			   `newline_anchor' is set, after newlines.  */
+		case begline:
+			DEBUG_PRINT1("EXECUTING begline.\n");
 
+			if (AT_STRINGS_BEG(d)) {
+				if (!bufp->not_bol)
+					break;
+			} else if (d[-1] == '\n' && bufp->newline_anchor) {
+				break;
+			}
+			/* In all other cases, we fail.  */
+			goto fail;
 
-		case notwordchar:
-			for (j = 0; j < (1 << BYTEWIDTH); j++)
-				if (SYNTAX(j) != Sword)
-					fastmap[j] = 1;
-			break;
 
+			/* endline is the dual of begline.  */
+		case endline:
+			DEBUG_PRINT1("EXECUTING endline.\n");
 
-		case anychar:
-		{
-			int fastmap_newline = fastmap['\n'];
+			if (AT_STRINGS_END(d)) {
+				if (!bufp->not_eol)
+					break;
+			}
 
-			/* `.' matches anything ...  */
-			for (j = 0; j < (1 << BYTEWIDTH); j++)
-				fastmap[j] = 1;
+			/* We have to ``prefetch'' the next character.  */
+			else if ((d == end1 ? *string2 : *d) == '\n'
+					 && bufp->newline_anchor) {
+				break;
+			}
+			goto fail;
 
-			/* ... except perhaps newline.  */
-			if (!(bufp->syntax & RE_DOT_NEWLINE))
-				fastmap['\n'] = fastmap_newline;
 
-			/* Return if we have already set `can_be_null'; if we have,
-			   then the fastmap is irrelevant.  Something's wrong here.  */
-			else if (bufp->can_be_null)
-				goto done;
+			/* Match at the very beginning of the data.  */
+		case begbuf:
+			DEBUG_PRINT1("EXECUTING begbuf.\n");
+			if (AT_STRINGS_BEG(d))
+				break;
+			goto fail;
 
-			/* Otherwise, have to check alternative paths.  */
-			break;
-		}
 
-#ifdef emacs
-		case syntaxspec:
-			k = *p++;
-			for (j = 0; j < (1 << BYTEWIDTH); j++)
-				if (SYNTAX(j) == (enum syntaxcode) k)
-					fastmap[j] = 1;
-			break;
+			/* Match at the very end of the data.  */
+		case endbuf:
+			DEBUG_PRINT1("EXECUTING endbuf.\n");
+			if (AT_STRINGS_END(d))
+				break;
+			goto fail;
 
 
-		case notsyntaxspec:
-			k = *p++;
-			for (j = 0; j < (1 << BYTEWIDTH); j++)
-				if (SYNTAX(j) != (enum syntaxcode) k)
-					fastmap[j] = 1;
-			break;
+			/* on_failure_keep_string_jump is used to optimize `.*\n'.  It
+			   pushes NULL as the value for the string on the stack.  Then
+			   `pop_failure_point' will keep the current value for the
+			   string, instead of restoring it.  To see why, consider
+			   matching `foo\nbar' against `.*\n'.  The .* matches the foo;
+			   then the . fails against the \n.  But the next thing we want
+			   to do is match the \n against the \n; if we restored the
+			   string value, we would be back at the foo.
+
+			   Because this is used only in specific cases, we don't need to
+			   check all the things that `on_failure_jump' does, to make
+			   sure the right things get saved on the stack.  Hence we don't
+			   share its code.  The only reason to push anything on the
+			   stack at all is that otherwise we would have to change
+			   `anychar's code to do something besides goto fail in this
+			   case; that seems worse than this.  */
+		case on_failure_keep_string_jump:
+			DEBUG_PRINT1("EXECUTING on_failure_keep_string_jump");
 
+			EXTRACT_NUMBER_AND_INCR(mcnt, p);
+#ifdef _LIBC
+			DEBUG_PRINT3(" %d (to %p):\n", mcnt, p + mcnt);
+#else
+			DEBUG_PRINT3(" %d (to 0x%x):\n", mcnt, p + mcnt);
+#endif
 
-			/* All cases after this match the empty string.  These end with
-			   `continue'.  */
+			PUSH_FAILURE_POINT(p + mcnt, NULL, -2);
+			break;
 
 
-		case before_dot:
-		case at_dot:
-		case after_dot:
-			continue;
-#endif							/* emacs */
+			/* Uses of on_failure_jump:
 
+			   Each alternative starts with an on_failure_jump that points
+			   to the beginning of the next alternative.  Each alternative
+			   except the last ends with a jump that in effect jumps past
+			   the rest of the alternatives.  (They really jump to the
+			   ending jump of the following alternative, because tensioning
+			   these jumps is a hassle.)
 
-		case no_op:
-		case begline:
-		case endline:
-		case begbuf:
-		case endbuf:
-		case wordbound:
-		case notwordbound:
-		case wordbeg:
-		case wordend:
-		case push_dummy_failure:
-			continue;
+			   Repeats start with an on_failure_jump that points past both
+			   the repetition text and either the following jump or
+			   pop_failure_jump back to this on_failure_jump.  */
+		case on_failure_jump:
+		  on_failure:
+			DEBUG_PRINT1("EXECUTING on_failure_jump");
 
+			EXTRACT_NUMBER_AND_INCR(mcnt, p);
+#ifdef _LIBC
+			DEBUG_PRINT3(" %d (to %p)", mcnt, p + mcnt);
+#else
+			DEBUG_PRINT3(" %d (to 0x%x)", mcnt, p + mcnt);
+#endif
 
-		case jump_n:
-		case pop_failure_jump:
-		case maybe_pop_jump:
-		case jump:
-		case jump_past_alt:
-		case dummy_failure_jump:
-			EXTRACT_NUMBER_AND_INCR(j, p);
-			p += j;
-			if (j > 0)
-				continue;
+			/* If this on_failure_jump comes right before a group (i.e.,
+			   the original * applied to a group), save the information
+			   for that group and all inner ones, so that if we fail back
+			   to this point, the group's information will be correct.
+			   For example, in \(a*\)*\1, we need the preceding group,
+			   and in \(zz\(a*\)b*\)\2, we need the inner group.  */
 
-			/* Jump backward implies we just went through the body of a
-			   loop and matched nothing.  Opcode jumped to should be
-			   `on_failure_jump' or `succeed_n'.  Just treat it like an
-			   ordinary jump.  For a * loop, it has pushed its failure
-			   point already; if so, discard that as redundant.  */
-			if ((re_opcode_t) * p != on_failure_jump
-				&& (re_opcode_t) * p != succeed_n)
-				continue;
+			/* We can't use `p' to check ahead because we push
+			   a failure point to `p + mcnt' after we do this.  */
+			p1 = p;
 
-			p++;
-			EXTRACT_NUMBER_AND_INCR(j, p);
-			p += j;
+			/* We need to skip no_op's before we look for the
+			   start_memory in case this on_failure_jump is happening as
+			   the result of a completed succeed_n, as in \(a\)\{1,3\}b\1
+			   against aba.  */
+			while (p1 < pend && (re_opcode_t) * p1 == no_op)
+				p1++;
 
-			/* If what's on the stack is where we are now, pop it.  */
-			if (!FAIL_STACK_EMPTY()
-				&& fail_stack.stack[fail_stack.avail - 1].pointer == p)
-				fail_stack.avail--;
+			if (p1 < pend && (re_opcode_t) * p1 == start_memory) {
+				/* We have a new highest active register now.  This will
+				   get reset at the start_memory we are about to get to,
+				   but we will have saved all the registers relevant to
+				   this repetition op, as described above.  */
+				highest_active_reg = *(p1 + 1) + *(p1 + 2);
+				if (lowest_active_reg == NO_LOWEST_ACTIVE_REG)
+					lowest_active_reg = *(p1 + 1);
+			}
 
-			continue;
+			DEBUG_PRINT1(":\n");
+			PUSH_FAILURE_POINT(p + mcnt, d, -2);
+			break;
 
 
-		case on_failure_jump:
-		case on_failure_keep_string_jump:
-		  handle_on_failure_jump:
-			EXTRACT_NUMBER_AND_INCR(j, p);
+			/* A smart repeat ends with `maybe_pop_jump'.
+			   We change it to either `pop_failure_jump' or `jump'.  */
+		case maybe_pop_jump:
+			EXTRACT_NUMBER_AND_INCR(mcnt, p);
+			DEBUG_PRINT2("EXECUTING maybe_pop_jump %d.\n", mcnt);
+			{
+				register unsigned char *p2 = p;
 
-			/* For some patterns, e.g., `(a?)?', `p+j' here points to the
-			   end of the pattern.  We don't want to push such a point,
-			   since when we restore it above, entering the switch will
-			   increment `p' past the end of the pattern.  We don't need
-			   to push such a point since we obviously won't find any more
-			   fastmap entries beyond `pend'.  Such a pattern can match
-			   the null string, though.  */
-			if (p + j < pend) {
-				if (!PUSH_PATTERN_OP(p + j, fail_stack)) {
-					RESET_FAIL_STACK();
-					return -2;
-				}
-			} else
-				bufp->can_be_null = 1;
+				/* Compare the beginning of the repeat with what in the
+				   pattern follows its end. If we can establish that there
+				   is nothing that they would both match, i.e., that we
+				   would have to backtrack because of (as in, e.g., `a*a')
+				   then we can change to pop_failure_jump, because we'll
+				   never have to backtrack.
 
-			if (succeed_n_p) {
-				EXTRACT_NUMBER_AND_INCR(k, p);	/* Skip the n.  */
-				succeed_n_p = false;
-			}
+				   This is not true in the case of alternatives: in
+				   `(a|ab)*' we do need to backtrack to the `ab' alternative
+				   (e.g., if the string was `ab').  But instead of trying to
+				   detect that here, the alternative has put on a dummy
+				   failure point which is what we will end up popping.  */
 
-			continue;
+				/* Skip over open/close-group commands.
+				   If what follows this loop is a ...+ construct,
+				   look at what begins its body, since we will have to
+				   match at least one of that.  */
+				while (1) {
+					if (p2 + 2 < pend
+						&& ((re_opcode_t) * p2 == stop_memory
+							|| (re_opcode_t) * p2 == start_memory))
+						p2 += 3;
+					else if (p2 + 6 < pend
+							 && (re_opcode_t) * p2 == dummy_failure_jump)
+							p2 += 6;
+					else
+						break;
+				}
 
+				p1 = p + mcnt;
+				/* p1[0] ... p1[2] are the `on_failure_jump' corresponding
+				   to the `maybe_finalize_jump' of this case.  Examine what
+				   follows.  */
 
-		case succeed_n:
-			/* Get to the number of times to succeed.  */
-			p += 2;
+				/* If we're at the end of the pattern, we can change.  */
+				if (p2 == pend) {
+					/* Consider what happens when matching ":\(.*\)"
+					   against ":/".  I don't really understand this code
+					   yet.  */
+					p[-3] = (unsigned char) pop_failure_jump;
+					DEBUG_PRINT1
+						("  End of pattern: change to `pop_failure_jump'.\n");
+				}
 
-			/* Increment p past the n for when k != 0.  */
-			EXTRACT_NUMBER_AND_INCR(k, p);
-			if (k == 0) {
-				p -= 4;
-				succeed_n_p = true;	/* Spaghetti code alert.  */
-				goto handle_on_failure_jump;
-			}
-			continue;
+				else if ((re_opcode_t) * p2 == exactn
+						 || (bufp->newline_anchor
+							 && (re_opcode_t) * p2 == endline)) {
+					register unsigned char c =
+						*p2 == (unsigned char) endline ? '\n' : p2[2];
 
+					if ((re_opcode_t) p1[3] == exactn && p1[5] != c) {
+						p[-3] = (unsigned char) pop_failure_jump;
+						DEBUG_PRINT3("  %c != %c => pop_failure_jump.\n",
+									 c, p1[5]);
+					}
 
-		case set_number_at:
-			p += 4;
-			continue;
+					else if ((re_opcode_t) p1[3] == charset
+							 || (re_opcode_t) p1[3] == charset_not) {
+						int not = (re_opcode_t) p1[3] == charset_not;
 
+						if (c < (unsigned char) (p1[4] * BYTEWIDTH)
+							&& p1[5 +
+								  c / BYTEWIDTH] & (1 << (c %
+														  BYTEWIDTH))) not
+								= !not;
 
-		case start_memory:
-		case stop_memory:
-			p += 2;
-			continue;
+						/* `not' is equal to 1 if c would match, which means
+						   that we can't change to pop_failure_jump.  */
+						if (!not) {
+							p[-3] = (unsigned char) pop_failure_jump;
+							DEBUG_PRINT1
+								("  No match => pop_failure_jump.\n");
+						}
+					}
+				} else if ((re_opcode_t) * p2 == charset) {
+					/* We win if the first character of the loop is not part
+					   of the charset.  */
+					if ((re_opcode_t) p1[3] == exactn
+						&& !((int) p2[1] * BYTEWIDTH > (int) p1[5]
+							 && (p2[2 + p1[5] / BYTEWIDTH]
+								 & (1 << (p1[5] % BYTEWIDTH))))) {
+						p[-3] = (unsigned char) pop_failure_jump;
+						DEBUG_PRINT1("  No match => pop_failure_jump.\n");
+					}
 
+					else if ((re_opcode_t) p1[3] == charset_not) {
+						int idx;
 
-		default:
-			abort();			/* We have listed all the cases.  */
-		}						/* switch *p++ */
+						/* We win if the charset_not inside the loop
+						   lists every character listed in the charset after.  */
+						for (idx = 0; idx < (int) p2[1]; idx++)
+							if (!(p2[2 + idx] == 0 || (idx < (int) p1[4]
+													   &&
+													   ((p2
+														 [2 +
+														  idx] & ~p1[5 +
+																	 idx])
+														== 0))))
+								break;
 
-		/* Getting here means we have found the possible starting
-		   characters for one path of the pattern -- and that the empty
-		   string does not match.  We need not follow this path further.
-		   Instead, look at the next alternative (remembered on the
-		   stack), or quit if no more.  The test at the top of the loop
-		   does these things.  */
-		path_can_be_null = false;
-		p = pend;
-	}							/* while p */
+						if (idx == p2[1]) {
+							p[-3] = (unsigned char) pop_failure_jump;
+							DEBUG_PRINT1
+								("  No match => pop_failure_jump.\n");
+						}
+					} else if ((re_opcode_t) p1[3] == charset) {
+						int idx;
 
-	/* Set `can_be_null' for the last path (also the first path, if the
-	   pattern is empty).  */
-	bufp->can_be_null |= path_can_be_null;
+						/* We win if the charset inside the loop
+						   has no overlap with the one after the loop.  */
+						for (idx = 0;
+							 idx < (int) p2[1] && idx < (int) p1[4]; idx++)
+							if ((p2[2 + idx] & p1[5 + idx]) != 0)
+								break;
 
-  done:
-	RESET_FAIL_STACK();
-	return 0;
-}								/* re_compile_fastmap */
+						if (idx == p2[1] || idx == p1[4]) {
+							p[-3] = (unsigned char) pop_failure_jump;
+							DEBUG_PRINT1
+								("  No match => pop_failure_jump.\n");
+						}
+					}
+				}
+			}
+			p -= 2;				/* Point at relative address again.  */
+			if ((re_opcode_t) p[-1] != pop_failure_jump) {
+				p[-1] = (unsigned char) jump;
+				DEBUG_PRINT1("  Match => jump.\n");
+				goto unconditional_jump;
+			}
+			/* Note fall through.  */
 
-#ifdef _LIBC
-weak_alias(__re_compile_fastmap, re_compile_fastmap)
-#endif
-/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
-   ENDS.  Subsequent matches using PATTERN_BUFFER and REGS will use
-   this memory for recording register information.  STARTS and ENDS
-   must be allocated using the malloc library routine, and must each
-   be at least NUM_REGS * sizeof (regoff_t) bytes long.
 
-   If NUM_REGS == 0, then subsequent matches should allocate their own
-   register data.
+			/* The end of a simple repeat has a pop_failure_jump back to
+			   its matching on_failure_jump, where the latter will push a
+			   failure point.  The pop_failure_jump takes off failure
+			   points put on by this pop_failure_jump's matching
+			   on_failure_jump; we got through the pattern to here from the
+			   matching on_failure_jump, so didn't fail.  */
+		case pop_failure_jump:
+		{
+			/* We need to pass separate storage for the lowest and
+			   highest registers, even though we don't care about the
+			   actual values.  Otherwise, we will restore only one
+			   register from the stack, since lowest will == highest in
+			   `pop_failure_point'.  */
+			active_reg_t dummy_low_reg, dummy_high_reg;
+			unsigned char *pdummy;
+			const char *sdummy;
 
-   Unless this function is called, the first search or match using
-   PATTERN_BUFFER will allocate its own register data, without
-   freeing the old data.  */
-void re_set_registers(bufp, regs, num_regs, starts, ends)
-struct re_pattern_buffer *bufp;
-struct re_registers *regs;
-unsigned num_regs;
-regoff_t *starts, *ends;
-{
-	if (num_regs) {
-		bufp->regs_allocated = REGS_REALLOCATE;
-		regs->num_regs = num_regs;
-		regs->start = starts;
-		regs->end = ends;
-	} else {
-		bufp->regs_allocated = REGS_UNALLOCATED;
-		regs->num_regs = 0;
-		regs->start = regs->end = (regoff_t *) 0;
-	}
-}
+			DEBUG_PRINT1("EXECUTING pop_failure_jump.\n");
+			POP_FAILURE_POINT(sdummy, pdummy,
+							  dummy_low_reg, dummy_high_reg,
+							  reg_dummy, reg_dummy, reg_info_dummy);
+		}
+			/* Note fall through.  */
 
+		  unconditional_jump:
 #ifdef _LIBC
-weak_alias(__re_set_registers, re_set_registers)
+			DEBUG_PRINT2("\n%p: ", p);
+#else
+			DEBUG_PRINT2("\n0x%x: ", p);
 #endif
-/* Searching routines.  */
-/* Like re_search_2, below, but only one string is specified, and
-   doesn't let you say where to stop matching. */
-int re_search(bufp, string, size, startpos, range, regs)
-struct re_pattern_buffer *bufp;
-const char *string;
-int size, startpos, range;
-struct re_registers *regs;
-{
-	return re_search_2(bufp, NULL, 0, string, size, startpos, range,
-					   regs, size);
-}
+			/* Note fall through.  */
 
+			/* Unconditionally jump (without popping any failure points).  */
+		case jump:
+			EXTRACT_NUMBER_AND_INCR(mcnt, p);	/* Get the amount to jump.  */
+			DEBUG_PRINT2("EXECUTING jump %d ", mcnt);
+			p += mcnt;			/* Do the jump.  */
 #ifdef _LIBC
-weak_alias(__re_search, re_search)
+			DEBUG_PRINT2("(to %p).\n", p);
+#else
+			DEBUG_PRINT2("(to 0x%x).\n", p);
 #endif
-/* Using the compiled pattern in BUFP->buffer, first tries to match the
-   virtual concatenation of STRING1 and STRING2, starting first at index
-   STARTPOS, then at STARTPOS + 1, and so on.
+			break;
 
-   STRING1 and STRING2 have length SIZE1 and SIZE2, respectively.
 
-   RANGE is how far to scan while trying to match.  RANGE = 0 means try
-   only at STARTPOS; in general, the last start tried is STARTPOS +
-   RANGE.
+			/* We need this opcode so we can detect where alternatives end
+			   in `group_match_null_string_p' et al.  */
+		case jump_past_alt:
+			DEBUG_PRINT1("EXECUTING jump_past_alt.\n");
+			goto unconditional_jump;
 
-   In REGS, return the indices of the virtual concatenation of STRING1
-   and STRING2 that matched the entire BUFP->buffer and its contained
-   subexpressions.
 
-   Do not consider matching one past the index STOP in the virtual
-   concatenation of STRING1 and STRING2.
+			/* Normally, the on_failure_jump pushes a failure point, which
+			   then gets popped at pop_failure_jump.  We will end up at
+			   pop_failure_jump, also, and with a pattern of, say, `a+', we
+			   are skipping over the on_failure_jump, so we have to push
+			   something meaningless for pop_failure_jump to pop.  */
+		case dummy_failure_jump:
+			DEBUG_PRINT1("EXECUTING dummy_failure_jump.\n");
+			/* It doesn't matter what we push for the string here.  What
+			   the code at `fail' tests is the value for the pattern.  */
+			PUSH_FAILURE_POINT(NULL, NULL, -2);
+			goto unconditional_jump;
 
-   We return either the position in the strings at which the match was
-   found, -1 if no match, or -2 if error (such as failure
-   stack overflow).  */
-int
-re_search_2(bufp, string1, size1, string2, size2, startpos, range, regs,
-			stop)
-struct re_pattern_buffer *bufp;
-const char *string1, *string2;
-int size1, size2;
-int startpos;
-int range;
-struct re_registers *regs;
-int stop;
-{
-	int val;
-	register char *fastmap = bufp->fastmap;
-	register RE_TRANSLATE_TYPE translate = bufp->translate;
-	int total_size = size1 + size2;
-	int endpos = startpos + range;
 
-	/* Check for out-of-range STARTPOS.  */
-	if (startpos < 0 || startpos > total_size)
-		return -1;
+			/* At the end of an alternative, we need to push a dummy failure
+			   point in case we are followed by a `pop_failure_jump', because
+			   we don't want the failure point for the alternative to be
+			   popped.  For example, matching `(a|ab)*' against `aab'
+			   requires that we match the `ab' alternative.  */
+		case push_dummy_failure:
+			DEBUG_PRINT1("EXECUTING push_dummy_failure.\n");
+			/* See comments just above at `dummy_failure_jump' about the
+			   two zeroes.  */
+			PUSH_FAILURE_POINT(NULL, NULL, -2);
+			break;
 
-	/* Fix up RANGE if it might eventually take us outside
-	   the virtual concatenation of STRING1 and STRING2.
-	   Make sure we won't move STARTPOS below 0 or above TOTAL_SIZE.  */
-	if (endpos < 0)
-		range = 0 - startpos;
-	else if (endpos > total_size)
-		range = total_size - startpos;
+			/* Have to succeed matching what follows at least n times.
+			   After that, handle like `on_failure_jump'.  */
+		case succeed_n:
+			EXTRACT_NUMBER(mcnt, p + 2);
+			DEBUG_PRINT2("EXECUTING succeed_n %d.\n", mcnt);
 
-	/* If the search isn't to be a backwards one, don't waste time in a
-	   search for a pattern that must be anchored.  */
-	if (bufp->used > 0 && range > 0
-		&& ((re_opcode_t) bufp->buffer[0] == begbuf
-			/* `begline' is like `begbuf' if it cannot match at newlines.  */
-			|| ((re_opcode_t) bufp->buffer[0] == begline
-				&& !bufp->newline_anchor))) {
-		if (startpos > 0)
-			return -1;
-		else
-			range = 1;
-	}
-#ifdef emacs
-	/* In a forward search for something that starts with \=.
-	   don't keep searching past point.  */
-	if (bufp->used > 0 && (re_opcode_t) bufp->buffer[0] == at_dot
-		&& range > 0) {
-		range = PT - startpos;
-		if (range <= 0)
-			return -1;
-	}
-#endif							/* emacs */
+			assert(mcnt >= 0);
+			/* Originally, this is how many times we HAVE to succeed.  */
+			if (mcnt > 0) {
+				mcnt--;
+				p += 2;
+				STORE_NUMBER_AND_INCR(p, mcnt);
+#ifdef _LIBC
+				DEBUG_PRINT3("  Setting %p to %d.\n", p - 2, mcnt);
+#else
+				DEBUG_PRINT3("  Setting 0x%x to %d.\n", p - 2, mcnt);
+#endif
+			} else if (mcnt == 0) {
+#ifdef _LIBC
+				DEBUG_PRINT2("  Setting two bytes from %p to no_op.\n",
+							 p + 2);
+#else
+				DEBUG_PRINT2("  Setting two bytes from 0x%x to no_op.\n",
+							 p + 2);
+#endif
+				p[2] = (unsigned char) no_op;
+				p[3] = (unsigned char) no_op;
+				goto on_failure;
+			}
+			break;
 
-	/* Update the fastmap now if not correct already.  */
-	if (fastmap && !bufp->fastmap_accurate)
-		if (re_compile_fastmap(bufp) == -2)
-			return -2;
+		case jump_n:
+			EXTRACT_NUMBER(mcnt, p + 2);
+			DEBUG_PRINT2("EXECUTING jump_n %d.\n", mcnt);
 
-	/* Loop through the string, looking for a place to start matching.  */
-	for (;;) {
-		/* If a fastmap is supplied, skip quickly over characters that
-		   cannot be the start of a match.  If the pattern can match the
-		   null string, however, we don't need to skip characters; we want
-		   the first null string.  */
-		if (fastmap && startpos < total_size && !bufp->can_be_null) {
-			if (range > 0) {	/* Searching forwards.  */
-				register const char *d;
-				register int lim = 0;
-				int irange = range;
+			/* Originally, this is how many times we CAN jump.  */
+			if (mcnt) {
+				mcnt--;
+				STORE_NUMBER(p + 2, mcnt);
+#ifdef _LIBC
+				DEBUG_PRINT3("  Setting %p to %d.\n", p + 2, mcnt);
+#else
+				DEBUG_PRINT3("  Setting 0x%x to %d.\n", p + 2, mcnt);
+#endif
+				goto unconditional_jump;
+			}
+			/* If don't have to jump any more, skip over the rest of command.  */
+			else
+				p += 4;
+			break;
 
-				if (startpos < size1 && startpos + range >= size1)
-					lim = range - (size1 - startpos);
+		case set_number_at:
+		{
+			DEBUG_PRINT1("EXECUTING set_number_at.\n");
 
-				d =
-					(startpos >=
-					 size1 ? string2 - size1 : string1) + startpos;
+			EXTRACT_NUMBER_AND_INCR(mcnt, p);
+			p1 = p + mcnt;
+			EXTRACT_NUMBER_AND_INCR(mcnt, p);
+#ifdef _LIBC
+			DEBUG_PRINT3("  Setting %p to %d.\n", p1, mcnt);
+#else
+			DEBUG_PRINT3("  Setting 0x%x to %d.\n", p1, mcnt);
+#endif
+			STORE_NUMBER(p1, mcnt);
+			break;
+		}
 
-				/* Written out as an if-else to avoid testing `translate'
-				   inside the loop.  */
-				if (translate)
-					while (range > lim && !fastmap[(unsigned char)
-												   translate[
-															 (unsigned
-															  char) *d++]])
-						range--;
-				else
-					while (range > lim && !fastmap[(unsigned char) *d++])
-						range--;
+#if 0
+			/* The DEC Alpha C compiler 3.x generates incorrect code for the
+			   test  WORDCHAR_P (d - 1) != WORDCHAR_P (d)  in the expansion of
+			   AT_WORD_BOUNDARY, so this code is disabled.  Expanding the
+			   macro and introducing temporary variables works around the bug.  */
+
+		case wordbound:
+			DEBUG_PRINT1("EXECUTING wordbound.\n");
+			if (AT_WORD_BOUNDARY(d))
+				break;
+			goto fail;
 
-				startpos += irange - range;
-			} else {			/* Searching backwards.  */
+		case notwordbound:
+			DEBUG_PRINT1("EXECUTING notwordbound.\n");
+			if (AT_WORD_BOUNDARY(d))
+				goto fail;
+			break;
+#else
+		case wordbound:
+		{
+			boolean prevchar, thischar;
 
-				register char c = (size1 == 0 || startpos >= size1
-								   ? string2[startpos - size1]
-								   : string1[startpos]);
+			DEBUG_PRINT1("EXECUTING wordbound.\n");
+			if (AT_STRINGS_BEG(d) || AT_STRINGS_END(d))
+				break;
 
-				if (!fastmap[(unsigned char) TRANSLATE(c)])
-					goto advance;
-			}
+			prevchar = WORDCHAR_P(d - 1);
+			thischar = WORDCHAR_P(d);
+			if (prevchar != thischar)
+				break;
+			goto fail;
 		}
 
-		/* If can't match the null string, and that's all we have left, fail.  */
-		if (range >= 0 && startpos == total_size && fastmap
-			&& !bufp->can_be_null) return -1;
-
-		val = re_match_2_internal(bufp, string1, size1, string2, size2,
-								  startpos, regs, stop);
-#ifndef REGEX_MALLOC
-# ifdef C_ALLOCA
-		alloca(0);
-# endif
-#endif
-
-		if (val >= 0)
-			return startpos;
+		case notwordbound:
+		{
+			boolean prevchar, thischar;
 
-		if (val == -2)
-			return -2;
+			DEBUG_PRINT1("EXECUTING notwordbound.\n");
+			if (AT_STRINGS_BEG(d) || AT_STRINGS_END(d))
+				goto fail;
 
-	  advance:
-		if (!range)
+			prevchar = WORDCHAR_P(d - 1);
+			thischar = WORDCHAR_P(d);
+			if (prevchar != thischar)
+				goto fail;
 			break;
-		else if (range > 0) {
-			range--;
-			startpos++;
-		} else {
-			range++;
-			startpos--;
 		}
-	}
-	return -1;
-}								/* re_search_2 */
-
-#ifdef _LIBC
-weak_alias(__re_search_2, re_search_2)
-#endif
-/* This converts PTR, a pointer into one of the search strings `string1'
-   and `string2' into an offset from the beginning of that string.  */
-#define POINTER_TO_OFFSET(ptr)			\
-  (FIRST_STRING_P (ptr)				\
-   ? ((regoff_t) ((ptr) - string1))		\
-   : ((regoff_t) ((ptr) - string2 + size1)))
-/* Macros for dealing with the split strings in re_match_2.  */
-#define MATCHING_IN_FIRST_STRING  (dend == end_match_1)
-/* Call before fetching a character with *d.  This switches over to
-   string2 if necessary.  */
-#define PREFETCH()							\
-  while (d == dend)						    	\
-    {									\
-      /* End of string2 => fail.  */					\
-      if (dend == end_match_2) 						\
-        goto fail;							\
-      /* End of string1 => advance to string2.  */ 			\
-      d = string2;						        \
-      dend = end_match_2;						\
-    }
-/* Test if at very beginning or at very end of the virtual concatenation
-   of `string1' and `string2'.  If only one string, it's `string2'.  */
-#define AT_STRINGS_BEG(d) ((d) == (size1 ? string1 : string2) || !size2)
-#define AT_STRINGS_END(d) ((d) == end2)
-/* Test if D points to a character which is word-constituent.  We have
-   two special cases to check for: if past the end of string1, look at
-   the first character in string2; and if before the beginning of
-   string2, look at the last character in string1.  */
-#define WORDCHAR_P(d)							\
-  (SYNTAX ((d) == end1 ? *string2					\
-           : (d) == string2 - 1 ? *(end1 - 1) : *(d))			\
-   == Sword)
-/* Disabled due to a compiler bug -- see comment at case wordbound */
-#if 0
-/* Test if the character before D and the one at D differ with respect
-   to being word-constituent.  */
-#define AT_WORD_BOUNDARY(d)						\
-  (AT_STRINGS_BEG (d) || AT_STRINGS_END (d)				\
-   || WORDCHAR_P (d - 1) != WORDCHAR_P (d))
 #endif
-/* Free everything we malloc.  */
-#ifdef MATCH_MAY_ALLOCATE
-# define FREE_VAR(var) if (var) REGEX_FREE (var); var = NULL
-# define FREE_VARIABLES()						\
-  do {									\
-    REGEX_FREE_STACK (fail_stack.stack);				\
-    FREE_VAR (regstart);						\
-    FREE_VAR (regend);							\
-    FREE_VAR (old_regstart);						\
-    FREE_VAR (old_regend);						\
-    FREE_VAR (best_regstart);						\
-    FREE_VAR (best_regend);						\
-    FREE_VAR (reg_info);						\
-    FREE_VAR (reg_dummy);						\
-    FREE_VAR (reg_info_dummy);						\
-  } while (0)
-#else
-# define FREE_VARIABLES() ((void)0)	/* Do nothing!  But inhibit gcc warning. */
-#endif							/* not MATCH_MAY_ALLOCATE */
-/* These values must meet several constraints.  They must not be valid
-   register values; since we have a limit of 255 registers (because
-   we use only one byte in the pattern for the register number), we can
-   use numbers larger than 255.  They must differ by 1, because of
-   NUM_FAILURE_ITEMS above.  And the value for the lowest register must
-   be larger than the value for the highest register, so we do not try
-   to actually save any registers when none are active.  */
-#define NO_HIGHEST_ACTIVE_REG (1 << BYTEWIDTH)
-#define NO_LOWEST_ACTIVE_REG (NO_HIGHEST_ACTIVE_REG + 1)
-/* Matching routines.  */
-#ifndef emacs					/* Emacs never uses this.  */
-/* re_match is like re_match_2 except it takes only a single string.  */
-int re_match(bufp, string, size, pos, regs)
-struct re_pattern_buffer *bufp;
-const char *string;
-int size, pos;
-struct re_registers *regs;
-{
-	int result = re_match_2_internal(bufp, NULL, 0, string, size,
-									 pos, regs, size);
 
-# ifndef REGEX_MALLOC
-#  ifdef C_ALLOCA
-	alloca(0);
-#  endif
-# endif
-	return result;
-}
+		case wordbeg:
+			DEBUG_PRINT1("EXECUTING wordbeg.\n");
+			if (WORDCHAR_P(d) && (AT_STRINGS_BEG(d) || !WORDCHAR_P(d - 1)))
+				break;
+			goto fail;
 
-# ifdef _LIBC
-weak_alias(__re_match, re_match)
-# endif
-#endif							/* not emacs */
-static boolean group_match_null_string_p _RE_ARGS((unsigned char **p,
-												   unsigned char *end,
-												   register_info_type *
+		case wordend:
+			DEBUG_PRINT1("EXECUTING wordend.\n");
+			if (!AT_STRINGS_BEG(d) && WORDCHAR_P(d - 1)
+				&& (!WORDCHAR_P(d) || AT_STRINGS_END(d)))
+				break;
+			goto fail;
 
-												   reg_info));
-static boolean alt_match_null_string_p
-_RE_ARGS(
+#ifdef emacs
+		case before_dot:
+			DEBUG_PRINT1("EXECUTING before_dot.\n");
+			if (PTR_CHAR_POS((unsigned char *) d) >= point)
+				goto fail;
+			break;
 
-		 (unsigned char *p, unsigned char *end,
-		  register_info_type * reg_info));
-static boolean common_op_match_null_string_p
-_RE_ARGS(
+		case at_dot:
+			DEBUG_PRINT1("EXECUTING at_dot.\n");
+			if (PTR_CHAR_POS((unsigned char *) d) != point)
+				goto fail;
+			break;
 
-		 (unsigned char **p, unsigned char *end,
-		  register_info_type * reg_info));
-static int bcmp_translate
-_RE_ARGS((const char *s1, const char *s2, int len, char *translate));
+		case after_dot:
+			DEBUG_PRINT1("EXECUTING after_dot.\n");
+			if (PTR_CHAR_POS((unsigned char *) d) <= point)
+				goto fail;
+			break;
 
-/* re_match_2 matches the compiled pattern in BUFP against the
-   the (virtual) concatenation of STRING1 and STRING2 (of length SIZE1
-   and SIZE2, respectively).  We start matching at POS, and stop
-   matching at STOP.
+		case syntaxspec:
+			DEBUG_PRINT2("EXECUTING syntaxspec %d.\n", mcnt);
+			mcnt = *p++;
+			goto matchsyntax;
 
-   If REGS is non-null and the `no_sub' field of BUFP is nonzero, we
-   store offsets for the substring each group matched in REGS.  See the
-   documentation for exactly how many groups we fill.
+		case wordchar:
+			DEBUG_PRINT1("EXECUTING Emacs wordchar.\n");
+			mcnt = (int) Sword;
+		  matchsyntax:
+			PREFETCH();
+			/* Can't use *d++ here; SYNTAX may be an unsafe macro.  */
+			d++;
+			if (SYNTAX(d[-1]) != (enum syntaxcode) mcnt)
+				goto fail;
+			SET_REGS_MATCHED();
+			break;
 
-   We return -1 if no match, -2 if an internal error (such as the
-   failure stack overflowing).  Otherwise, we return the length of the
-   matched substring.  */
+		case notsyntaxspec:
+			DEBUG_PRINT2("EXECUTING notsyntaxspec %d.\n", mcnt);
+			mcnt = *p++;
+			goto matchnotsyntax;
 
-int re_match_2(bufp, string1, size1, string2, size2, pos, regs, stop)
-struct re_pattern_buffer *bufp;
-const char *string1, *string2;
-int size1, size2;
-int pos;
-struct re_registers *regs;
-int stop;
-{
-	int result = re_match_2_internal(bufp, string1, size1, string2, size2,
-									 pos, regs, stop);
+		case notwordchar:
+			DEBUG_PRINT1("EXECUTING Emacs notwordchar.\n");
+			mcnt = (int) Sword;
+		  matchnotsyntax:
+			PREFETCH();
+			/* Can't use *d++ here; SYNTAX may be an unsafe macro.  */
+			d++;
+			if (SYNTAX(d[-1]) == (enum syntaxcode) mcnt)
+				goto fail;
+			SET_REGS_MATCHED();
+			break;
 
-#ifndef REGEX_MALLOC
-# ifdef C_ALLOCA
-	alloca(0);
-# endif
-#endif
-	return result;
-}
+#else							/* not emacs */
+		case wordchar:
+			DEBUG_PRINT1("EXECUTING non-Emacs wordchar.\n");
+			PREFETCH();
+			if (!WORDCHAR_P(d))
+				goto fail;
+			SET_REGS_MATCHED();
+			d++;
+			break;
 
-#ifdef _LIBC
-weak_alias(__re_match_2, re_match_2)
-#endif
-/* This is a separate function so that we can force an alloca cleanup
-   afterwards.  */
-static int
-re_match_2_internal(bufp, string1, size1, string2, size2, pos, regs, stop)
-struct re_pattern_buffer *bufp;
-const char *string1, *string2;
-int size1, size2;
-int pos;
-struct re_registers *regs;
-int stop;
-{
-	/* General temporaries.  */
-	int mcnt;
-	unsigned char *p1;
+		case notwordchar:
+			DEBUG_PRINT1("EXECUTING non-Emacs notwordchar.\n");
+			PREFETCH();
+			if (WORDCHAR_P(d))
+				goto fail;
+			SET_REGS_MATCHED();
+			d++;
+			break;
+#endif							/* not emacs */
 
-	/* Just past the end of the corresponding string.  */
-	const char *end1, *end2;
+		default:
+			abort();
+		}
+		continue;				/* Successfully executed one pattern command; keep going.  */
 
-	/* Pointers into string1 and string2, just past the last characters in
-	   each to consider matching.  */
-	const char *end_match_1, *end_match_2;
 
-	/* Where we are in the data, and the end of the current string.  */
-	const char *d, *dend;
+		/* We goto here if a matching operation fails. */
+	  fail:
+		if (!FAIL_STACK_EMPTY()) {	/* A restart point is known.  Restore to that state.  */
+			DEBUG_PRINT1("\nFAIL:\n");
+			POP_FAILURE_POINT(d, p,
+							  lowest_active_reg, highest_active_reg,
+							  regstart, regend, reg_info);
 
-	/* Where we are in the pattern, and the end of the pattern.  */
-	unsigned char *p = bufp->buffer;
-	register unsigned char *pend = p + bufp->used;
+			/* If this failure point is a dummy, try the next one.  */
+			if (!p)
+				goto fail;
 
-	/* Mark the opcode just after a start_memory, so we can test for an
-	   empty subpattern when we get to the stop_memory.  */
-	unsigned char *just_past_start_mem = 0;
+			/* If we failed to the end of the pattern, don't examine *p.  */
+			assert(p <= pend);
+			if (p < pend) {
+				boolean is_a_jump_n = false;
 
-	/* We use this to map every character in the string.  */
-	RE_TRANSLATE_TYPE translate = bufp->translate;
+				/* If failed to a backwards jump that's part of a repetition
+				   loop, need to pop this failure point and use the next one.  */
+				switch ((re_opcode_t) * p) {
+				case jump_n:
+					is_a_jump_n = true;
+				case maybe_pop_jump:
+				case pop_failure_jump:
+				case jump:
+					p1 = p + 1;
+					EXTRACT_NUMBER_AND_INCR(mcnt, p1);
+					p1 += mcnt;
 
-	/* Failure point stack.  Each place that can handle a failure further
-	   down the line pushes a failure point on this stack.  It consists of
-	   restart, regend, and reg_info for all registers corresponding to
-	   the subexpressions we're currently inside, plus the number of such
-	   registers, and, finally, two char *'s.  The first char * is where
-	   to resume scanning the pattern; the second one is where to resume
-	   scanning the strings.  If the latter is zero, the failure point is
-	   a ``dummy''; if a failure happens and the failure point is a dummy,
-	   it gets discarded and the next next one is tried.  */
-#ifdef MATCH_MAY_ALLOCATE		/* otherwise, this is global.  */
-	fail_stack_type fail_stack;
-#endif
-#ifdef DEBUG
-	static unsigned failure_id;
-	unsigned nfailure_points_pushed = 0, nfailure_points_popped = 0;
-#endif
+					if ((is_a_jump_n && (re_opcode_t) * p1 == succeed_n)
+						|| (!is_a_jump_n
+							&& (re_opcode_t) * p1 == on_failure_jump))
+							goto fail;
+					break;
+				default:
+					/* do nothing */ ;
+				}
+			}
 
-#ifdef REL_ALLOC
-	/* This holds the pointer to the failure stack, when
-	   it is allocated relocatably.  */
-	fail_stack_elt_t *failure_stack_ptr;
-#endif
+			if (d >= string1 && d <= end1)
+				dend = end_match_1;
+		} else
+			break;				/* Matching at this starting point really fails.  */
+	}							/* for (;;) */
 
-	/* We fill all the registers internally, independent of what we
-	   return, for use in backreferences.  The number here includes
-	   an element for register zero.  */
-	size_t num_regs = bufp->re_nsub + 1;
+	if (best_regs_set)
+		goto restore_best_regs;
 
-	/* The currently active registers.  */
-	active_reg_t lowest_active_reg = NO_LOWEST_ACTIVE_REG;
-	active_reg_t highest_active_reg = NO_HIGHEST_ACTIVE_REG;
+	FREE_VARIABLES();
 
-	/* Information on the contents of registers. These are pointers into
-	   the input strings; they record just what was matched (on this
-	   attempt) by a subexpression part of the pattern, that is, the
-	   regnum-th regstart pointer points to where in the pattern we began
-	   matching and the regnum-th regend points to right after where we
-	   stopped matching the regnum-th subexpression.  (The zeroth register
-	   keeps track of what the whole pattern matches.)  */
-#ifdef MATCH_MAY_ALLOCATE		/* otherwise, these are global.  */
-	const char **regstart, **regend;
-#endif
+	return -1;					/* Failure to match.  */
+}								/* re_match_2 */
+
+/* Subroutine definitions for re_match_2.  */
 
-	/* If a group that's operated upon by a repetition operator fails to
-	   match anything, then the register for its start will need to be
-	   restored because it will have been set to wherever in the string we
-	   are when we last see its open-group operator.  Similarly for a
-	   register's end.  */
-#ifdef MATCH_MAY_ALLOCATE		/* otherwise, these are global.  */
-	const char **old_regstart, **old_regend;
-#endif
 
-	/* The is_active field of reg_info helps us keep track of which (possibly
-	   nested) subexpressions we are currently in. The matched_something
-	   field of reg_info[reg_num] helps us tell whether or not we have
-	   matched any of the pattern so far this time through the reg_num-th
-	   subexpression.  These two fields get reset each time through any
-	   loop their register is in.  */
-#ifdef MATCH_MAY_ALLOCATE		/* otherwise, this is global.  */
-	register_info_type *reg_info;
-#endif
+/* We are passed P pointing to a register number after a start_memory.
 
-	/* The following record the register info as found in the above
-	   variables when we find a match better than any we've seen before.
-	   This happens as we backtrack through the failure points, which in
-	   turn happens only if we have not yet matched the entire string. */
-	unsigned best_regs_set = false;
+   Return true if the pattern up to the corresponding stop_memory can
+   match the empty string, and false otherwise.
 
-#ifdef MATCH_MAY_ALLOCATE		/* otherwise, these are global.  */
-	const char **best_regstart, **best_regend;
-#endif
+   If we find the matching stop_memory, sets P to point to one past its number.
+   Otherwise, sets P to an undefined byte less than or equal to END.
 
-	/* Logically, this is `best_regend[0]'.  But we don't want to have to
-	   allocate space for that if we're not allocating space for anything
-	   else (see below).  Also, we never need info about register 0 for
-	   any of the other register vectors, and it seems rather a kludge to
-	   treat `best_regend' differently than the rest.  So we keep track of
-	   the end of the best match so far in a separate variable.  We
-	   initialize this to NULL so that when we backtrack the first time
-	   and need to test it, it's not garbage.  */
-	const char *match_end = NULL;
+   We don't handle duplicates properly (yet).  */
 
-	/* This helps SET_REGS_MATCHED avoid doing redundant work.  */
-	int set_regs_matched_done = 0;
+static boolean group_match_null_string_p(p, end, reg_info)
+unsigned char **p, *end;
+register_info_type *reg_info;
+{
+	int mcnt;
 
-	/* Used when we pop values we don't care about.  */
-#ifdef MATCH_MAY_ALLOCATE		/* otherwise, these are global.  */
-	const char **reg_dummy;
-	register_info_type *reg_info_dummy;
-#endif
+	/* Point to after the args to the start_memory.  */
+	unsigned char *p1 = *p + 2;
 
-#ifdef DEBUG
-	/* Counts the total number of registers pushed.  */
-	unsigned num_regs_pushed = 0;
-#endif
+	while (p1 < end) {
+		/* Skip over opcodes that can match nothing, and return true or
+		   false, as appropriate, when we get to one that can't, or to the
+		   matching stop_memory.  */
 
-	DEBUG_PRINT1("\n\nEntering re_match_2.\n");
+		switch ((re_opcode_t) * p1) {
+			/* Could be either a loop or a series of alternatives.  */
+		case on_failure_jump:
+			p1++;
+			EXTRACT_NUMBER_AND_INCR(mcnt, p1);
 
-	INIT_FAIL_STACK();
+			/* If the next operation is not a jump backwards in the
+			   pattern.  */
 
-#ifdef MATCH_MAY_ALLOCATE
-	/* Do not bother to initialize all the register variables if there are
-	   no groups in the pattern, as it takes a fair amount of time.  If
-	   there are groups, we include space for register 0 (the whole
-	   pattern), even though we never use it, since it simplifies the
-	   array indexing.  We should fix this.  */
-	if (bufp->re_nsub) {
-		regstart = REGEX_TALLOC(num_regs, const char *);
-		regend = REGEX_TALLOC(num_regs, const char *);
-		old_regstart = REGEX_TALLOC(num_regs, const char *);
-		old_regend = REGEX_TALLOC(num_regs, const char *);
-		best_regstart = REGEX_TALLOC(num_regs, const char *);
-		best_regend = REGEX_TALLOC(num_regs, const char *);
+			if (mcnt >= 0) {
+				/* Go through the on_failure_jumps of the alternatives,
+				   seeing if any of the alternatives cannot match nothing.
+				   The last alternative starts with only a jump,
+				   whereas the rest start with on_failure_jump and end
+				   with a jump, e.g., here is the pattern for `a|b|c':
 
-		reg_info = REGEX_TALLOC(num_regs, register_info_type);
-		reg_dummy = REGEX_TALLOC(num_regs, const char *);
+				   /on_failure_jump/0/6/exactn/1/a/jump_past_alt/0/6
+				   /on_failure_jump/0/6/exactn/1/b/jump_past_alt/0/3
+				   /exactn/1/c
 
-		reg_info_dummy = REGEX_TALLOC(num_regs, register_info_type);
+				   So, we have to first go through the first (n-1)
+				   alternatives and then deal with the last one separately.  */
 
-		if (!(regstart && regend && old_regstart && old_regend && reg_info
-			  && best_regstart && best_regend && reg_dummy
-			  && reg_info_dummy)) {
-			FREE_VARIABLES();
-			return -2;
-		}
-	} else {
-		/* We must initialize all our variables to NULL, so that
-		   `FREE_VARIABLES' doesn't try to free them.  */
-		regstart = regend = old_regstart = old_regend = best_regstart
-			= best_regend = reg_dummy = NULL;
-		reg_info = reg_info_dummy = (register_info_type *) NULL;
-	}
-#endif							/* MATCH_MAY_ALLOCATE */
 
-	/* The starting position is bogus.  */
-	if (pos < 0 || pos > size1 + size2) {
-		FREE_VARIABLES();
-		return -1;
-	}
+				/* Deal with the first (n-1) alternatives, which start
+				   with an on_failure_jump (see above) that jumps to right
+				   past a jump_past_alt.  */
 
-	/* Initialize subexpression text positions to -1 to mark ones that no
-	   start_memory/stop_memory has been seen for. Also initialize the
-	   register information struct.  */
-	for (mcnt = 1; (unsigned) mcnt < num_regs; mcnt++) {
-		regstart[mcnt] = regend[mcnt]
-			= old_regstart[mcnt] = old_regend[mcnt] = REG_UNSET_VALUE;
+				while ((re_opcode_t) p1[mcnt - 3] == jump_past_alt) {
+					/* `mcnt' holds how many bytes long the alternative
+					   is, including the ending `jump_past_alt' and
+					   its number.  */
 
-		REG_MATCH_NULL_STRING_P(reg_info[mcnt]) = MATCH_NULL_UNSET_VALUE;
-		IS_ACTIVE(reg_info[mcnt]) = 0;
-		MATCHED_SOMETHING(reg_info[mcnt]) = 0;
-		EVER_MATCHED_SOMETHING(reg_info[mcnt]) = 0;
-	}
+					if (!alt_match_null_string_p(p1, p1 + mcnt - 3,
+												 reg_info)) return false;
 
-	/* We move `string1' into `string2' if the latter's empty -- but not if
-	   `string1' is null.  */
-	if (size2 == 0 && string1 != NULL) {
-		string2 = string1;
-		size2 = size1;
-		string1 = 0;
-		size1 = 0;
-	}
-	end1 = string1 + size1;
-	end2 = string2 + size2;
+					/* Move to right after this alternative, including the
+					   jump_past_alt.  */
+					p1 += mcnt;
 
-	/* Compute where to stop matching, within the two strings.  */
-	if (stop <= size1) {
-		end_match_1 = string1 + stop;
-		end_match_2 = string2;
-	} else {
-		end_match_1 = end1;
-		end_match_2 = string2 + stop - size1;
-	}
+					/* Break if it's the beginning of an n-th alternative
+					   that doesn't begin with an on_failure_jump.  */
+					if ((re_opcode_t) * p1 != on_failure_jump)
+						break;
 
-	/* `p' scans through the pattern as `d' scans through the data.
-	   `dend' is the end of the input string that `d' points within.  `d'
-	   is advanced into the following input string whenever necessary, but
-	   this happens before fetching; therefore, at the beginning of the
-	   loop, `d' can be pointing at the end of a string, but it cannot
-	   equal `string2'.  */
-	if (size1 > 0 && pos <= size1) {
-		d = string1 + pos;
-		dend = end_match_1;
-	} else {
-		d = string2 + pos - size1;
-		dend = end_match_2;
-	}
+					/* Still have to check that it's not an n-th
+					   alternative that starts with an on_failure_jump.  */
+					p1++;
+					EXTRACT_NUMBER_AND_INCR(mcnt, p1);
+					if ((re_opcode_t) p1[mcnt - 3] != jump_past_alt) {
+						/* Get to the beginning of the n-th alternative.  */
+						p1 -= 3;
+						break;
+					}
+				}
 
-	DEBUG_PRINT1("The compiled pattern is:\n");
-	DEBUG_PRINT_COMPILED_PATTERN(bufp, p, pend);
-	DEBUG_PRINT1("The string to match is: `");
-	DEBUG_PRINT_DOUBLE_STRING(d, string1, size1, string2, size2);
-	DEBUG_PRINT1("'\n");
+				/* Deal with the last alternative: go back and get number
+				   of the `jump_past_alt' just before it.  `mcnt' contains
+				   the length of the alternative.  */
+				EXTRACT_NUMBER(mcnt, p1 - 2);
 
-	/* This loops over pattern commands.  It exits by returning from the
-	   function if the match is complete, or it drops through if the match
-	   fails at this starting point in the input data.  */
-	for (;;) {
-#ifdef _LIBC
-		DEBUG_PRINT2("\n%p: ", p);
-#else
-		DEBUG_PRINT2("\n0x%x: ", p);
-#endif
+				if (!alt_match_null_string_p(p1, p1 + mcnt, reg_info))
+					return false;
 
-		if (p == pend) {		/* End of pattern means we might have succeeded.  */
-			DEBUG_PRINT1("end of pattern ... ");
+				p1 += mcnt;		/* Get past the n-th alternative.  */
+			}					/* if mcnt > 0 */
+			break;
 
-			/* If we haven't matched the entire string, and we want the
-			   longest match, try backtracking.  */
-			if (d != end_match_2) {
-				/* 1 if this match ends in the same string (string1 or string2)
-				   as the best previous match.  */
-				boolean same_str_p = (FIRST_STRING_P(match_end)
-									  == MATCHING_IN_FIRST_STRING);
 
-				/* 1 if this match is the best seen so far.  */
-				boolean best_match_p;
+		case stop_memory:
+			assert(p1[1] == **p);
+			*p = p1 + 2;
+			return true;
 
-				/* AIX compiler got confused when this was combined
-				   with the previous declaration.  */
-				if (same_str_p)
-					best_match_p = d > match_end;
-				else
-					best_match_p = !MATCHING_IN_FIRST_STRING;
 
-				DEBUG_PRINT1("backtracking.\n");
+		default:
+			if (!common_op_match_null_string_p(&p1, end, reg_info))
+				return false;
+		}
+	}							/* while p1 < end */
 
-				if (!FAIL_STACK_EMPTY()) {	/* More failure points to try.  */
+	return false;
+}								/* group_match_null_string_p */
 
-					/* If exceeds best match so far, save it.  */
-					if (!best_regs_set || best_match_p) {
-						best_regs_set = true;
-						match_end = d;
 
-						DEBUG_PRINT1("\nSAVING match as best so far.\n");
+/* Similar to group_match_null_string_p, but doesn't deal with alternatives:
+   It expects P to be the first byte of a single alternative and END one
+   byte past the last. The alternative can contain groups.  */
 
-						for (mcnt = 1; (unsigned) mcnt < num_regs; mcnt++) {
-							best_regstart[mcnt] = regstart[mcnt];
-							best_regend[mcnt] = regend[mcnt];
-						}
-					}
-					goto fail;
-				}
+static boolean alt_match_null_string_p(p, end, reg_info)
+unsigned char *p, *end;
+register_info_type *reg_info;
+{
+	int mcnt;
+	unsigned char *p1 = p;
 
-				/* If no failure points, don't restore garbage.  And if
-				   last match is real best match, don't restore second
-				   best one. */
-				else if (best_regs_set && !best_match_p) {
-				  restore_best_regs:
-					/* Restore best match.  It may happen that `dend ==
-					   end_match_1' while the restored d is in string2.
-					   For example, the pattern `x.*y.*z' against the
-					   strings `x-' and `y-z-', if the two strings are
-					   not consecutive in memory.  */
-					DEBUG_PRINT1("Restoring best registers.\n");
+	while (p1 < end) {
+		/* Skip over opcodes that can match nothing, and break when we get
+		   to one that can't.  */
 
-					d = match_end;
-					dend = ((d >= string1 && d <= end1)
-							? end_match_1 : end_match_2);
+		switch ((re_opcode_t) * p1) {
+			/* It's a loop.  */
+		case on_failure_jump:
+			p1++;
+			EXTRACT_NUMBER_AND_INCR(mcnt, p1);
+			p1 += mcnt;
+			break;
 
-					for (mcnt = 1; (unsigned) mcnt < num_regs; mcnt++) {
-						regstart[mcnt] = best_regstart[mcnt];
-						regend[mcnt] = best_regend[mcnt];
-					}
-				}
-			}
-			/* d != end_match_2 */
-		  succeed_label:
-			DEBUG_PRINT1("Accepting match.\n");
+		default:
+			if (!common_op_match_null_string_p(&p1, end, reg_info))
+				return false;
+		}
+	}							/* while p1 < end */
 
-			/* If caller wants register contents data back, do it.  */
-			if (regs && !bufp->no_sub) {
-				/* Have the register data arrays been allocated?  */
-				if (bufp->regs_allocated == REGS_UNALLOCATED) {	/* No.  So allocate them with malloc.  We need one
-																   extra element beyond `num_regs' for the `-1' marker
-																   GNU code uses.  */
-					regs->num_regs = MAX(RE_NREGS, num_regs + 1);
-					regs->start = TALLOC(regs->num_regs, regoff_t);
-					regs->end = TALLOC(regs->num_regs, regoff_t);
-					if (regs->start == NULL || regs->end == NULL) {
-						FREE_VARIABLES();
-						return -2;
-					}
-					bufp->regs_allocated = REGS_REALLOCATE;
-				} else if (bufp->regs_allocated == REGS_REALLOCATE) {	/* Yes.  If we need more elements than were already
-																		   allocated, reallocate them.  If we need fewer, just
-																		   leave it alone.  */
-					if (regs->num_regs < num_regs + 1) {
-						regs->num_regs = num_regs + 1;
-						RETALLOC(regs->start, regs->num_regs, regoff_t);
-						RETALLOC(regs->end, regs->num_regs, regoff_t);
-						if (regs->start == NULL || regs->end == NULL) {
-							FREE_VARIABLES();
-							return -2;
-						}
-					}
-				} else {
-					/* These braces fend off a "empty body in an else-statement"
-					   warning under GCC when assert expands to nothing.  */
-					assert(bufp->regs_allocated == REGS_FIXED);
-				}
+	return true;
+}								/* alt_match_null_string_p */
 
-				/* Convert the pointer data in `regstart' and `regend' to
-				   indices.  Register zero has to be set differently,
-				   since we haven't kept track of any info for it.  */
-				if (regs->num_regs > 0) {
-					regs->start[0] = pos;
-					regs->end[0] = (MATCHING_IN_FIRST_STRING
-									? ((regoff_t) (d - string1))
-									: ((regoff_t) (d - string2 + size1)));
-				}
 
-				/* Go through the first `min (num_regs, regs->num_regs)'
-				   registers, since that is all we initialized.  */
-				for (mcnt = 1;
-					 (unsigned) mcnt < MIN(num_regs, regs->num_regs);
-					 mcnt++) {
-					if (REG_UNSET(regstart[mcnt])
-						|| REG_UNSET(regend[mcnt])) regs->start[mcnt] =
-							regs->end[mcnt] = -1;
-					else {
-						regs->start[mcnt]
-							= (regoff_t) POINTER_TO_OFFSET(regstart[mcnt]);
-						regs->end[mcnt]
-							= (regoff_t) POINTER_TO_OFFSET(regend[mcnt]);
-					}
-				}
+/* Deals with the ops common to group_match_null_string_p and
+   alt_match_null_string_p.
 
-				/* If the regs structure we return has more elements than
-				   were in the pattern, set the extra elements to -1.  If
-				   we (re)allocated the registers, this is the case,
-				   because we always allocate enough to have at least one
-				   -1 at the end.  */
-				for (mcnt = num_regs; (unsigned) mcnt < regs->num_regs;
-					 mcnt++)
-					regs->start[mcnt] = regs->end[mcnt] = -1;
-			}
-			/* regs && !bufp->no_sub */
-			DEBUG_PRINT4
-				("%u failure points pushed, %u popped (%u remain).\n",
-				 nfailure_points_pushed, nfailure_points_popped,
-				 nfailure_points_pushed - nfailure_points_popped);
-			DEBUG_PRINT2("%u registers pushed.\n", num_regs_pushed);
+   Sets P to one after the op and its arguments, if any.  */
+
+static boolean common_op_match_null_string_p(p, end, reg_info)
+unsigned char **p, *end;
+register_info_type *reg_info;
+{
+	int mcnt;
+	boolean ret;
+	int reg_no;
+	unsigned char *p1 = *p;
 
-			mcnt = d - pos - (MATCHING_IN_FIRST_STRING
-							  ? string1 : string2 - size1);
+	switch ((re_opcode_t) * p1++) {
+	case no_op:
+	case begline:
+	case endline:
+	case begbuf:
+	case endbuf:
+	case wordbeg:
+	case wordend:
+	case wordbound:
+	case notwordbound:
+#ifdef emacs
+	case before_dot:
+	case at_dot:
+	case after_dot:
+#endif
+		break;
 
-			DEBUG_PRINT2("Returning %d from re_match_2.\n", mcnt);
+	case start_memory:
+		reg_no = *p1;
+		assert(reg_no > 0 && reg_no <= MAX_REGNUM);
+		ret = group_match_null_string_p(&p1, end, reg_info);
 
-			FREE_VARIABLES();
-			return mcnt;
-		}
+		/* Have to set this here in case we're checking a group which
+		   contains a group and a back reference to it.  */
 
-		/* Otherwise match next pattern command.  */
-		switch (SWITCH_ENUM_CAST((re_opcode_t) * p++)) {
-			/* Ignore these.  Used to ignore the n of succeed_n's which
-			   currently have n == 0.  */
-		case no_op:
-			DEBUG_PRINT1("EXECUTING no_op.\n");
-			break;
+		if (REG_MATCH_NULL_STRING_P(reg_info[reg_no]) ==
+			MATCH_NULL_UNSET_VALUE)
+				REG_MATCH_NULL_STRING_P(reg_info[reg_no]) = ret;
 
-		case succeed:
-			DEBUG_PRINT1("EXECUTING succeed.\n");
-			goto succeed_label;
+		if (!ret)
+			return false;
+		break;
 
-			/* Match the next n pattern characters exactly.  The following
-			   byte in the pattern defines n, and the n bytes after that
-			   are the characters to match.  */
-		case exactn:
-			mcnt = *p++;
-			DEBUG_PRINT2("EXECUTING exactn %d.\n", mcnt);
+		/* If this is an optimized succeed_n for zero times, make the jump.  */
+	case jump:
+		EXTRACT_NUMBER_AND_INCR(mcnt, p1);
+		if (mcnt >= 0)
+			p1 += mcnt;
+		else
+			return false;
+		break;
 
-			/* This is written out as an if-else so we don't waste time
-			   testing `translate' inside the loop.  */
-			if (translate) {
-				do {
-					PREFETCH();
-					if ((unsigned char) translate[(unsigned char) *d++]
-						!= (unsigned char) *p++)
-						goto fail;
-				}
-				while (--mcnt);
-			} else {
-				do {
-					PREFETCH();
-					if (*d++ != (char) *p++)
-						goto fail;
-				}
-				while (--mcnt);
-			}
-			SET_REGS_MATCHED();
-			break;
+	case succeed_n:
+		/* Get to the number of times to succeed.  */
+		p1 += 2;
+		EXTRACT_NUMBER_AND_INCR(mcnt, p1);
 
+		if (mcnt == 0) {
+			p1 -= 4;
+			EXTRACT_NUMBER_AND_INCR(mcnt, p1);
+			p1 += mcnt;
+		} else
+			return false;
+		break;
 
-			/* Match any character except possibly a newline or a null.  */
-		case anychar:
-			DEBUG_PRINT1("EXECUTING anychar.\n");
+	case duplicate:
+		if (!REG_MATCH_NULL_STRING_P(reg_info[*p1]))
+			return false;
+		break;
 
-			PREFETCH();
+	case set_number_at:
+		p1 += 4;
 
-			if ((!(bufp->syntax & RE_DOT_NEWLINE) && TRANSLATE(*d) == '\n')
-				|| (bufp->syntax & RE_DOT_NOT_NULL
-					&& TRANSLATE(*d) == '\000')) goto fail;
+	default:
+		/* All other opcodes mean we cannot match the empty string.  */
+		return false;
+	}
 
-			SET_REGS_MATCHED();
-			DEBUG_PRINT2("  Matched `%d'.\n", *d);
-			d++;
-			break;
+	*p = p1;
+	return true;
+}								/* common_op_match_null_string_p */
 
 
-		case charset:
-		case charset_not:
-		{
-			register unsigned char c;
-			boolean not = (re_opcode_t) * (p - 1) == charset_not;
+/* Return zero if TRANSLATE[S1] and TRANSLATE[S2] are identical for LEN
+   bytes; nonzero otherwise.  */
 
-			DEBUG_PRINT2("EXECUTING charset%s.\n", not ? "_not" : "");
+static int bcmp_translate(s1, s2, len, translate)
+const char *s1, *s2;
+register int len;
+RE_TRANSLATE_TYPE translate;
+{
+	register const unsigned char *p1 = (const unsigned char *) s1;
+	register const unsigned char *p2 = (const unsigned char *) s2;
 
-			PREFETCH();
-			c = TRANSLATE(*d);	/* The character to match.  */
+	while (len) {
+		if (translate[*p1++] != translate[*p2++])
+			return 1;
+		len--;
+	}
+	return 0;
+}
+
+/* Entry points for GNU code.  */
 
-			/* Cast to `unsigned' instead of `unsigned char' in case the
-			   bit list is a full 32 bytes long.  */
-			if (c < (unsigned) (*p * BYTEWIDTH)
-				&& p[1 + c / BYTEWIDTH] & (1 << (c % BYTEWIDTH)))
-				not = !not;
+/* re_compile_pattern is the GNU regular expression compiler: it
+   compiles PATTERN (of length SIZE) and puts the result in BUFP.
+   Returns 0 if the pattern was valid, otherwise an error string.
 
-			p += 1 + *p;
+   Assumes the `allocated' (and perhaps `buffer') and `translate' fields
+   are set in BUFP on entry.
 
-			if (!not)
-				goto fail;
+   We call regex_compile to do the actual compilation.  */
 
-			SET_REGS_MATCHED();
-			d++;
-			break;
-		}
+const char *re_compile_pattern(pattern, length, bufp)
+const char *pattern;
+size_t length;
+struct re_pattern_buffer *bufp;
+{
+	reg_errcode_t ret;
 
+	/* GNU code is written to assume at least RE_NREGS registers will be set
+	   (and at least one extra will be -1).  */
+	bufp->regs_allocated = REGS_UNALLOCATED;
 
-			/* The beginning of a group is represented by start_memory.
-			   The arguments are the register number in the next byte, and the
-			   number of groups inner to this one in the next.  The text
-			   matched within the group is recorded (in the internal
-			   registers data structure) under the register number.  */
-		case start_memory:
-			DEBUG_PRINT3("EXECUTING start_memory %d (%d):\n", *p, p[1]);
+	/* And GNU code determines whether or not to get register information
+	   by passing null for the REGS argument to re_match, etc., not by
+	   setting no_sub.  */
+	bufp->no_sub = 0;
 
-			/* Find out if this group can match the empty string.  */
-			p1 = p;				/* To send to group_match_null_string_p.  */
+	/* Match anchors at newline.  */
+	bufp->newline_anchor = 1;
 
-			if (REG_MATCH_NULL_STRING_P(reg_info[*p]) ==
-				MATCH_NULL_UNSET_VALUE)
-					REG_MATCH_NULL_STRING_P(reg_info[*p]) =
-					group_match_null_string_p(&p1, pend, reg_info);
+	ret = regex_compile(pattern, length, re_syntax_options, bufp);
 
-			/* Save the position in the string where we were the last time
-			   we were at this open-group operator in case the group is
-			   operated upon by a repetition operator, e.g., with `(a*)*b'
-			   against `ab'; then we want to ignore where we are now in
-			   the string in case this attempt to match fails.  */
-			old_regstart[*p] = REG_MATCH_NULL_STRING_P(reg_info[*p])
-				? REG_UNSET(regstart[*p]) ? d : regstart[*p]
-				: regstart[*p];
-			DEBUG_PRINT2("  old_regstart: %d\n",
-						 POINTER_TO_OFFSET(old_regstart[*p]));
+	if (!ret)
+		return NULL;
+	return gettext(re_error_msgid + re_error_msgid_idx[(int) ret]);
+}
 
-			regstart[*p] = d;
-			DEBUG_PRINT2("  regstart: %d\n",
-						 POINTER_TO_OFFSET(regstart[*p]));
+#ifdef _LIBC
+weak_alias(__re_compile_pattern, re_compile_pattern)
+#endif
+/* Entry points compatible with 4.2 BSD regex library.  We don't define
+   them unless specifically requested.  */
+#if defined _REGEX_RE_COMP || defined _LIBC
+/* BSD has one and only one pattern buffer.  */
+static struct re_pattern_buffer re_comp_buf;
 
-			IS_ACTIVE(reg_info[*p]) = 1;
-			MATCHED_SOMETHING(reg_info[*p]) = 0;
+char *
+#ifdef _LIBC
+/* Make these definitions weak in libc, so POSIX programs can redefine
+   these names if they don't use our functions, and still use
+   regcomp/regexec below without link errors.  */ weak_function
+#endif
+re_comp(s)
+const char *s;
+{
+	reg_errcode_t ret;
 
-			/* Clear this whenever we change the register activity status.  */
-			set_regs_matched_done = 0;
+	if (!s) {
+		if (!re_comp_buf.buffer)
+			return gettext("No previous regular expression");
+		return 0;
+	}
 
-			/* This is the new highest active register.  */
-			highest_active_reg = *p;
+	if (!re_comp_buf.buffer) {
+		re_comp_buf.buffer = (unsigned char *) malloc(200);
+		if (re_comp_buf.buffer == NULL)
+			return (char *) gettext(re_error_msgid
+									+
+									re_error_msgid_idx[(int) REG_ESPACE]);
+		re_comp_buf.allocated = 200;
 
-			/* If nothing was active before, this is the new lowest active
-			   register.  */
-			if (lowest_active_reg == NO_LOWEST_ACTIVE_REG)
-				lowest_active_reg = *p;
+		re_comp_buf.fastmap = (char *) malloc(1 << BYTEWIDTH);
+		if (re_comp_buf.fastmap == NULL)
+			return (char *) gettext(re_error_msgid
+									+
+									re_error_msgid_idx[(int) REG_ESPACE]);
+	}
+
+	/* Since `re_exec' always passes NULL for the `regs' argument, we
+	   don't need to initialize the pattern buffer fields which affect it.  */
 
-			/* Move past the register number and inner group count.  */
-			p += 2;
-			just_past_start_mem = p;
+	/* Match anchors at newlines.  */
+	re_comp_buf.newline_anchor = 1;
 
-			break;
+	ret = regex_compile(s, strlen(s), re_syntax_options, &re_comp_buf);
 
+	if (!ret)
+		return NULL;
 
-			/* The stop_memory opcode represents the end of a group.  Its
-			   arguments are the same as start_memory's: the register
-			   number, and the number of inner groups.  */
-		case stop_memory:
-			DEBUG_PRINT3("EXECUTING stop_memory %d (%d):\n", *p, p[1]);
+	/* Yes, we're discarding `const' here if !HAVE_LIBINTL.  */
+	return (char *) gettext(re_error_msgid +
+							re_error_msgid_idx[(int) ret]);
+}
 
-			/* We need to save the string position the last time we were at
-			   this close-group operator in case the group is operated
-			   upon by a repetition operator, e.g., with `((a*)*(b*)*)*'
-			   against `aba'; then we want to ignore where we are now in
-			   the string in case this attempt to match fails.  */
-			old_regend[*p] = REG_MATCH_NULL_STRING_P(reg_info[*p])
-				? REG_UNSET(regend[*p]) ? d : regend[*p]
-				: regend[*p];
-			DEBUG_PRINT2("      old_regend: %d\n",
-						 POINTER_TO_OFFSET(old_regend[*p]));
 
-			regend[*p] = d;
-			DEBUG_PRINT2("      regend: %d\n",
-						 POINTER_TO_OFFSET(regend[*p]));
+int
+#ifdef _LIBC
+ weak_function
+#endif
+re_exec(s)
+const char *s;
+{
+	const int len = strlen(s);
 
-			/* This register isn't active anymore.  */
-			IS_ACTIVE(reg_info[*p]) = 0;
+	return
+		0 <= re_search(&re_comp_buf, s, len, 0, len,
+					   (struct re_registers *) 0);
+}
 
-			/* Clear this whenever we change the register activity status.  */
-			set_regs_matched_done = 0;
+#endif							/* _REGEX_RE_COMP */
+
+/* POSIX.2 functions.  Don't define these for Emacs.  */
 
-			/* If this was the only register active, nothing is active
-			   anymore.  */
-			if (lowest_active_reg == highest_active_reg) {
-				lowest_active_reg = NO_LOWEST_ACTIVE_REG;
-				highest_active_reg = NO_HIGHEST_ACTIVE_REG;
-			} else {			/* We must scan for the new highest active register, since
-								   it isn't necessarily one less than now: consider
-								   (a(b)c(d(e)f)g).  When group 3 ends, after the f), the
-								   new highest active register is 1.  */
-				unsigned char r = *p - 1;
+#ifndef emacs
 
-				while (r > 0 && !IS_ACTIVE(reg_info[r]))
-					r--;
+/* regcomp takes a regular expression as a string and compiles it.
 
-				/* If we end up at register zero, that means that we saved
-				   the registers as the result of an `on_failure_jump', not
-				   a `start_memory', and we jumped to past the innermost
-				   `stop_memory'.  For example, in ((.)*) we save
-				   registers 1 and 2 as a result of the *, but when we pop
-				   back to the second ), we are at the stop_memory 1.
-				   Thus, nothing is active.  */
-				if (r == 0) {
-					lowest_active_reg = NO_LOWEST_ACTIVE_REG;
-					highest_active_reg = NO_HIGHEST_ACTIVE_REG;
-				} else
-					highest_active_reg = r;
-			}
+   PREG is a regex_t *.  We do not expect any fields to be initialized,
+   since POSIX says we shouldn't.  Thus, we set
 
-			/* If just failed to match something this time around with a
-			   group that's operated on by a repetition operator, try to
-			   force exit from the ``loop'', and restore the register
-			   information for this group that we had before trying this
-			   last match.  */
-			if ((!MATCHED_SOMETHING(reg_info[*p])
-				 || just_past_start_mem == p - 1)
-				&& (p + 2) < pend) {
-				boolean is_a_jump_n = false;
+     `buffer' to the compiled pattern;
+     `used' to the length of the compiled pattern;
+     `syntax' to RE_SYNTAX_POSIX_EXTENDED if the
+       REG_EXTENDED bit in CFLAGS is set; otherwise, to
+       RE_SYNTAX_POSIX_BASIC;
+     `newline_anchor' to REG_NEWLINE being set in CFLAGS;
+     `fastmap' to an allocated space for the fastmap;
+     `fastmap_accurate' to zero;
+     `re_nsub' to the number of subexpressions in PATTERN.
 
-				p1 = p + 2;
-				mcnt = 0;
-				switch ((re_opcode_t) * p1++) {
-				case jump_n:
-					is_a_jump_n = true;
-				case pop_failure_jump:
-				case maybe_pop_jump:
-				case jump:
-				case dummy_failure_jump:
-					EXTRACT_NUMBER_AND_INCR(mcnt, p1);
-					if (is_a_jump_n)
-						p1 += 2;
-					break;
+   PATTERN is the address of the pattern string.
 
-				default:
-					/* do nothing */ ;
-				}
-				p1 += mcnt;
+   CFLAGS is a series of bits which affect compilation.
 
-				/* If the next operation is a jump backwards in the pattern
-				   to an on_failure_jump right before the start_memory
-				   corresponding to this stop_memory, exit from the loop
-				   by forcing a failure after pushing on the stack the
-				   on_failure_jump's jump in the pattern, and d.  */
-				if (mcnt < 0 && (re_opcode_t) * p1 == on_failure_jump
-					&& (re_opcode_t) p1[3] == start_memory && p1[4] == *p) {
-					/* If this group ever matched anything, then restore
-					   what its registers were before trying this last
-					   failed match, e.g., with `(a*)*b' against `ab' for
-					   regstart[1], and, e.g., with `((a*)*(b*)*)*'
-					   against `aba' for regend[3].
+     If REG_EXTENDED is set, we use POSIX extended syntax; otherwise, we
+     use POSIX basic syntax.
 
-					   Also restore the registers for inner groups for,
-					   e.g., `((a*)(b*))*' against `aba' (register 3 would
-					   otherwise get trashed).  */
+     If REG_NEWLINE is set, then . and [^...] don't match newline.
+     Also, regexec will try a match beginning after every newline.
 
-					if (EVER_MATCHED_SOMETHING(reg_info[*p])) {
-						unsigned r;
+     If REG_ICASE is set, then we considers upper- and lowercase
+     versions of letters to be equivalent when matching.
 
-						EVER_MATCHED_SOMETHING(reg_info[*p]) = 0;
+     If REG_NOSUB is set, then when PREG is passed to regexec, that
+     routine will report only success or failure, and nothing about the
+     registers.
 
-						/* Restore this and inner groups' (if any) registers.  */
-						for (r = *p;
-							 r < (unsigned) *p + (unsigned) *(p + 1); r++) {
-							regstart[r] = old_regstart[r];
+   It returns 0 if it succeeds, nonzero if it doesn't.  (See regex.h for
+   the return codes and their meanings.)  */
 
-							/* xx why this test?  */
-							if (old_regend[r] >= regstart[r])
-								regend[r] = old_regend[r];
-						}
-					}
-					p1++;
-					EXTRACT_NUMBER_AND_INCR(mcnt, p1);
-					PUSH_FAILURE_POINT(p1 + mcnt, d, -2);
+int regcomp(preg, pattern, cflags)
+regex_t *preg;
+const char *pattern;
+int cflags;
+{
+	reg_errcode_t ret;
+	reg_syntax_t syntax
+		= (cflags & REG_EXTENDED) ?
 
-					goto fail;
-				}
-			}
+		RE_SYNTAX_POSIX_EXTENDED : RE_SYNTAX_POSIX_BASIC;
 
-			/* Move past the register number and the inner group count.  */
-			p += 2;
-			break;
+	/* regex_compile will allocate the space for the compiled pattern.  */
+	preg->buffer = 0;
+	preg->allocated = 0;
+	preg->used = 0;
 
+	/* Try to allocate space for the fastmap.  */
+	preg->fastmap = (char *) malloc(1 << BYTEWIDTH);
 
-			/* \<digit> has been turned into a `duplicate' command which is
-			   followed by the numeric value of <digit> as the register number.  */
-		case duplicate:
-		{
-			register const char *d2, *dend2;
-			int regno = *p++;	/* Get which register to match against.  */
+	if (cflags & REG_ICASE) {
+		unsigned i;
 
-			DEBUG_PRINT2("EXECUTING duplicate %d.\n", regno);
+		preg->translate
+			= (RE_TRANSLATE_TYPE) malloc(CHAR_SET_SIZE
+										 * sizeof(*(RE_TRANSLATE_TYPE) 0));
+		if (preg->translate == NULL)
+			return (int) REG_ESPACE;
 
-			/* Can't back reference a group which we've never matched.  */
-			if (REG_UNSET(regstart[regno]) || REG_UNSET(regend[regno]))
-				goto fail;
+		/* Map uppercase characters to corresponding lowercase ones.  */
+		for (i = 0; i < CHAR_SET_SIZE; i++)
+			preg->translate[i] = ISUPPER(i) ? TOLOWER(i) : i;
+	} else
+		preg->translate = NULL;
 
-			/* Where in input to try to start matching.  */
-			d2 = regstart[regno];
+	/* If REG_NEWLINE is set, newlines are treated differently.  */
+	if (cflags & REG_NEWLINE) {	/* REG_NEWLINE implies neither . nor [^...] match newline.  */
+		syntax &= ~RE_DOT_NEWLINE;
+		syntax |= RE_HAT_LISTS_NOT_NEWLINE;
+		/* It also changes the matching behavior.  */
+		preg->newline_anchor = 1;
+	} else
+		preg->newline_anchor = 0;
 
-			/* Where to stop matching; if both the place to start and
-			   the place to stop matching are in the same string, then
-			   set to the place to stop, otherwise, for now have to use
-			   the end of the first string.  */
+	preg->no_sub = !!(cflags & REG_NOSUB);
 
-			dend2 = ((FIRST_STRING_P(regstart[regno])
-					  == FIRST_STRING_P(regend[regno]))
-					 ? regend[regno] : end_match_1);
-			for (;;) {
-				/* If necessary, advance to next segment in register
-				   contents.  */
-				while (d2 == dend2) {
-					if (dend2 == end_match_2)
-						break;
-					if (dend2 == regend[regno])
-						break;
+	/* POSIX says a null character in the pattern terminates it, so we
+	   can use strlen here in compiling the pattern.  */
+	ret = regex_compile(pattern, strlen(pattern), syntax, preg);
 
-					/* End of string1 => advance to string2. */
-					d2 = string2;
-					dend2 = regend[regno];
-				}
-				/* At end of register contents => success */
-				if (d2 == dend2)
-					break;
+	/* POSIX doesn't distinguish between an unmatched open-group and an
+	   unmatched close-group: both are REG_EPAREN.  */
+	if (ret == REG_ERPAREN)
+		ret = REG_EPAREN;
 
-				/* If necessary, advance to next segment in data.  */
-				PREFETCH();
+	if (ret == REG_NOERROR && preg->fastmap) {
+		/* Compute the fastmap now, since regexec cannot modify the pattern
+		   buffer.  */
+		if (re_compile_fastmap(preg) == -2) {
+			/* Some error occurred while computing the fastmap, just forget
+			   about it.  */
+			free(preg->fastmap);
+			preg->fastmap = NULL;
+		}
+	}
+
+	return (int) ret;
+}
 
-				/* How many characters left in this segment to match.  */
-				mcnt = dend - d;
+#ifdef _LIBC
+weak_alias(__regcomp, regcomp)
+#endif
+/* regexec searches for a given pattern, specified by PREG, in the
+   string STRING.
 
-				/* Want how many consecutive characters we can match in
-				   one shot, so, if necessary, adjust the count.  */
-				if (mcnt > dend2 - d2)
-					mcnt = dend2 - d2;
+   If NMATCH is zero or REG_NOSUB was set in the cflags argument to
+   `regcomp', we ignore PMATCH.  Otherwise, we assume PMATCH has at
+   least NMATCH elements, and we set them to the offsets of the
+   corresponding matched substrings.
 
-				/* Compare that many; failure if mismatch, else move
-				   past them.  */
-				if (translate ? bcmp_translate(d, d2, mcnt, translate)
-					: memcmp(d, d2, mcnt))
-					goto fail;
-				d += mcnt, d2 += mcnt;
+   EFLAGS specifies `execution flags' which affect matching: if
+   REG_NOTBOL is set, then ^ does not match at the beginning of the
+   string; if REG_NOTEOL is set, then $ does not match at the end.
 
-				/* Do this because we've match some characters.  */
-				SET_REGS_MATCHED();
-			}
-		}
-			break;
+   We return 0 if we find a match and REG_NOMATCH if not.  */
+int regexec(preg, string, nmatch, pmatch, eflags)
+const regex_t *preg;
+const char *string;
+size_t nmatch;
+regmatch_t pmatch[];
+int eflags;
+{
+	int ret;
+	struct re_registers regs;
+	regex_t private_preg;
+	int len = strlen(string);
+	boolean want_reg_info = !preg->no_sub && nmatch > 0;
 
+	private_preg = *preg;
 
-			/* begline matches the empty string at the beginning of the string
-			   (unless `not_bol' is set in `bufp'), and, if
-			   `newline_anchor' is set, after newlines.  */
-		case begline:
-			DEBUG_PRINT1("EXECUTING begline.\n");
+	private_preg.not_bol = !!(eflags & REG_NOTBOL);
+	private_preg.not_eol = !!(eflags & REG_NOTEOL);
 
-			if (AT_STRINGS_BEG(d)) {
-				if (!bufp->not_bol)
-					break;
-			} else if (d[-1] == '\n' && bufp->newline_anchor) {
-				break;
-			}
-			/* In all other cases, we fail.  */
-			goto fail;
+	/* The user has told us exactly how many registers to return
+	   information about, via `nmatch'.  We have to pass that on to the
+	   matching routines.  */
+	private_preg.regs_allocated = REGS_FIXED;
 
+	if (want_reg_info) {
+		regs.num_regs = nmatch;
+		regs.start = TALLOC(nmatch * 2, regoff_t);
+		if (regs.start == NULL)
+			return (int) REG_NOMATCH;
+		regs.end = regs.start + nmatch;
+	}
 
-			/* endline is the dual of begline.  */
-		case endline:
-			DEBUG_PRINT1("EXECUTING endline.\n");
+	/* Perform the searching operation.  */
+	ret = re_search(&private_preg, string, len,
+					/* start: */ 0, /* range: */ len,
+					want_reg_info ? &regs : (struct re_registers *) 0);
 
-			if (AT_STRINGS_END(d)) {
-				if (!bufp->not_eol)
-					break;
-			}
+	/* Copy the register information to the POSIX structure.  */
+	if (want_reg_info) {
+		if (ret >= 0) {
+			unsigned r;
 
-			/* We have to ``prefetch'' the next character.  */
-			else if ((d == end1 ? *string2 : *d) == '\n'
-					 && bufp->newline_anchor) {
-				break;
+			for (r = 0; r < nmatch; r++) {
+				pmatch[r].rm_so = regs.start[r];
+				pmatch[r].rm_eo = regs.end[r];
 			}
-			goto fail;
-
+		}
 
-			/* Match at the very beginning of the data.  */
-		case begbuf:
-			DEBUG_PRINT1("EXECUTING begbuf.\n");
-			if (AT_STRINGS_BEG(d))
-				break;
-			goto fail;
+		/* If we needed the temporary register info, free the space now.  */
+		free(regs.start);
+	}
 
+	/* We want zero return to mean success, unlike `re_search'.  */
+	return ret >= 0 ? (int) REG_NOERROR : (int) REG_NOMATCH;
+}
 
-			/* Match at the very end of the data.  */
-		case endbuf:
-			DEBUG_PRINT1("EXECUTING endbuf.\n");
-			if (AT_STRINGS_END(d))
-				break;
-			goto fail;
+#ifdef _LIBC
+weak_alias(__regexec, regexec)
+#endif
+/* Returns a message corresponding to an error code, ERRCODE, returned
+   from either regcomp or regexec.   We don't use PREG here.  */
+	size_t regerror(errcode, preg, errbuf, errbuf_size)
+int errcode;
+const regex_t *preg;
+char *errbuf;
+size_t errbuf_size;
+{
+	const char *msg;
+	size_t msg_size;
 
+	if (errcode < 0 || errcode >= (int) (sizeof(re_error_msgid_idx)
+										 / sizeof(re_error_msgid_idx[0])))
+		/* Only error codes returned by the rest of the code should be passed
+		   to this routine.  If we are given anything else, or if other regex
+		   code generates an invalid error code, then the program has a bug.
+		   Dump core so we can fix it.  */
+		abort();
 
-			/* on_failure_keep_string_jump is used to optimize `.*\n'.  It
-			   pushes NULL as the value for the string on the stack.  Then
-			   `pop_failure_point' will keep the current value for the
-			   string, instead of restoring it.  To see why, consider
-			   matching `foo\nbar' against `.*\n'.  The .* matches the foo;
-			   then the . fails against the \n.  But the next thing we want
-			   to do is match the \n against the \n; if we restored the
-			   string value, we would be back at the foo.
+	msg = gettext(re_error_msgid + re_error_msgid_idx[errcode]);
 
-			   Because this is used only in specific cases, we don't need to
-			   check all the things that `on_failure_jump' does, to make
-			   sure the right things get saved on the stack.  Hence we don't
-			   share its code.  The only reason to push anything on the
-			   stack at all is that otherwise we would have to change
-			   `anychar's code to do something besides goto fail in this
-			   case; that seems worse than this.  */
-		case on_failure_keep_string_jump:
-			DEBUG_PRINT1("EXECUTING on_failure_keep_string_jump");
+	msg_size = strlen(msg) + 1;	/* Includes the null.  */
 
-			EXTRACT_NUMBER_AND_INCR(mcnt, p);
-#ifdef _LIBC
-			DEBUG_PRINT3(" %d (to %p):\n", mcnt, p + mcnt);
+	if (errbuf_size != 0) {
+		if (msg_size > errbuf_size) {
+#if defined HAVE_MEMPCPY || defined _LIBC
+			*((char *) __mempcpy(errbuf, msg, errbuf_size - 1)) = '\0';
 #else
-			DEBUG_PRINT3(" %d (to 0x%x):\n", mcnt, p + mcnt);
+			memcpy(errbuf, msg, errbuf_size - 1);
+			errbuf[errbuf_size - 1] = 0;
 #endif
+		} else
+			memcpy(errbuf, msg, msg_size);
+	}
 
-			PUSH_FAILURE_POINT(p + mcnt, NULL, -2);
-			break;
+	return msg_size;
+}
 
+#ifdef _LIBC
+weak_alias(__regerror, regerror)
+#endif
+/* Free dynamically allocated space used by PREG.  */
+void regfree(preg)
+regex_t *preg;
+{
+	if (preg->buffer != NULL)
+		free(preg->buffer);
+	preg->buffer = NULL;
 
-			/* Uses of on_failure_jump:
+	preg->allocated = 0;
+	preg->used = 0;
 
-			   Each alternative starts with an on_failure_jump that points
-			   to the beginning of the next alternative.  Each alternative
-			   except the last ends with a jump that in effect jumps past
-			   the rest of the alternatives.  (They really jump to the
-			   ending jump of the following alternative, because tensioning
-			   these jumps is a hassle.)
+	if (preg->fastmap != NULL)
+		free(preg->fastmap);
+	preg->fastmap = NULL;
+	preg->fastmap_accurate = 0;
 
-			   Repeats start with an on_failure_jump that points past both
-			   the repetition text and either the following jump or
-			   pop_failure_jump back to this on_failure_jump.  */
-		case on_failure_jump:
-		  on_failure:
-			DEBUG_PRINT1("EXECUTING on_failure_jump");
+	if (preg->translate != NULL)
+		free(preg->translate);
+	preg->translate = NULL;
+}
 
-			EXTRACT_NUMBER_AND_INCR(mcnt, p);
 #ifdef _LIBC
-			DEBUG_PRINT3(" %d (to %p)", mcnt, p + mcnt);
-#else
-			DEBUG_PRINT3(" %d (to 0x%x)", mcnt, p + mcnt);
+weak_alias(__regfree, regfree)
 #endif
+#endif							/* not emacs  */
+
+/* `regex_compile' compiles PATTERN (of length SIZE) according to SYNTAX.
+   Returns one of error codes defined in `regex.h', or zero for success.
 
-			/* If this on_failure_jump comes right before a group (i.e.,
-			   the original * applied to a group), save the information
-			   for that group and all inner ones, so that if we fail back
-			   to this point, the group's information will be correct.
-			   For example, in \(a*\)*\1, we need the preceding group,
-			   and in \(zz\(a*\)b*\)\2, we need the inner group.  */
+   Assumes the `allocated' (and perhaps `buffer') and `translate'
+   fields are set in BUFP on entry.
 
-			/* We can't use `p' to check ahead because we push
-			   a failure point to `p + mcnt' after we do this.  */
-			p1 = p;
+   If it succeeds, results are put in BUFP (if it returns an error, the
+   contents of BUFP are undefined):
+     `buffer' is the compiled pattern;
+     `syntax' is set to SYNTAX;
+     `used' is set to the length of the compiled pattern;
+     `fastmap_accurate' is zero;
+     `re_nsub' is the number of subexpressions in PATTERN;
+     `not_bol' and `not_eol' are zero;
 
-			/* We need to skip no_op's before we look for the
-			   start_memory in case this on_failure_jump is happening as
-			   the result of a completed succeed_n, as in \(a\)\{1,3\}b\1
-			   against aba.  */
-			while (p1 < pend && (re_opcode_t) * p1 == no_op)
-				p1++;
+   The `fastmap' and `newline_anchor' fields are neither
+   examined nor set.  */
 
-			if (p1 < pend && (re_opcode_t) * p1 == start_memory) {
-				/* We have a new highest active register now.  This will
-				   get reset at the start_memory we are about to get to,
-				   but we will have saved all the registers relevant to
-				   this repetition op, as described above.  */
-				highest_active_reg = *(p1 + 1) + *(p1 + 2);
-				if (lowest_active_reg == NO_LOWEST_ACTIVE_REG)
-					lowest_active_reg = *(p1 + 1);
-			}
+/* Return, freeing storage we allocated.  */
+#define FREE_STACK_RETURN(value)		\
+  return (free (compile_stack.stack), value)
 
-			DEBUG_PRINT1(":\n");
-			PUSH_FAILURE_POINT(p + mcnt, d, -2);
-			break;
+static reg_errcode_t regex_compile(pattern, size, syntax, bufp)
+const char *pattern;
+size_t size;
+reg_syntax_t syntax;
+struct re_pattern_buffer *bufp;
+{
+	/* We fetch characters from PATTERN here.  Even though PATTERN is
+	   `char *' (i.e., signed), we declare these variables as unsigned, so
+	   they can be reliably used as array indices.  */
+	register unsigned char c, c1;
 
+	/* A random temporary spot in PATTERN.  */
+	const char *p1;
 
-			/* A smart repeat ends with `maybe_pop_jump'.
-			   We change it to either `pop_failure_jump' or `jump'.  */
-		case maybe_pop_jump:
-			EXTRACT_NUMBER_AND_INCR(mcnt, p);
-			DEBUG_PRINT2("EXECUTING maybe_pop_jump %d.\n", mcnt);
-			{
-				register unsigned char *p2 = p;
+	/* Points to the end of the buffer, where we should append.  */
+	register unsigned char *b;
 
-				/* Compare the beginning of the repeat with what in the
-				   pattern follows its end. If we can establish that there
-				   is nothing that they would both match, i.e., that we
-				   would have to backtrack because of (as in, e.g., `a*a')
-				   then we can change to pop_failure_jump, because we'll
-				   never have to backtrack.
+	/* Keeps track of unclosed groups.  */
+	compile_stack_type compile_stack;
 
-				   This is not true in the case of alternatives: in
-				   `(a|ab)*' we do need to backtrack to the `ab' alternative
-				   (e.g., if the string was `ab').  But instead of trying to
-				   detect that here, the alternative has put on a dummy
-				   failure point which is what we will end up popping.  */
+	/* Points to the current (ending) position in the pattern.  */
+	const char *p = pattern;
+	const char *pend = pattern + size;
 
-				/* Skip over open/close-group commands.
-				   If what follows this loop is a ...+ construct,
-				   look at what begins its body, since we will have to
-				   match at least one of that.  */
-				while (1) {
-					if (p2 + 2 < pend
-						&& ((re_opcode_t) * p2 == stop_memory
-							|| (re_opcode_t) * p2 == start_memory))
-						p2 += 3;
-					else if (p2 + 6 < pend
-							 && (re_opcode_t) * p2 == dummy_failure_jump)
-							p2 += 6;
-					else
-						break;
-				}
+	/* How to translate the characters in the pattern.  */
+	RE_TRANSLATE_TYPE translate = bufp->translate;
 
-				p1 = p + mcnt;
-				/* p1[0] ... p1[2] are the `on_failure_jump' corresponding
-				   to the `maybe_finalize_jump' of this case.  Examine what
-				   follows.  */
+	/* Address of the count-byte of the most recently inserted `exactn'
+	   command.  This makes it possible to tell if a new exact-match
+	   character can be added to that command or if the character requires
+	   a new `exactn' command.  */
+	unsigned char *pending_exact = 0;
 
-				/* If we're at the end of the pattern, we can change.  */
-				if (p2 == pend) {
-					/* Consider what happens when matching ":\(.*\)"
-					   against ":/".  I don't really understand this code
-					   yet.  */
-					p[-3] = (unsigned char) pop_failure_jump;
-					DEBUG_PRINT1
-						("  End of pattern: change to `pop_failure_jump'.\n");
-				}
+	/* Address of start of the most recently finished expression.
+	   This tells, e.g., postfix * where to find the start of its
+	   operand.  Reset at the beginning of groups and alternatives.  */
+	unsigned char *laststart = 0;
 
-				else if ((re_opcode_t) * p2 == exactn
-						 || (bufp->newline_anchor
-							 && (re_opcode_t) * p2 == endline)) {
-					register unsigned char c =
-						*p2 == (unsigned char) endline ? '\n' : p2[2];
+	/* Address of beginning of regexp, or inside of last group.  */
+	unsigned char *begalt;
 
-					if ((re_opcode_t) p1[3] == exactn && p1[5] != c) {
-						p[-3] = (unsigned char) pop_failure_jump;
-						DEBUG_PRINT3("  %c != %c => pop_failure_jump.\n",
-									 c, p1[5]);
-					}
+	/* Place in the uncompiled pattern (i.e., the {) to
+	   which to go back if the interval is invalid.  */
+	const char *beg_interval;
 
-					else if ((re_opcode_t) p1[3] == charset
-							 || (re_opcode_t) p1[3] == charset_not) {
-						int not = (re_opcode_t) p1[3] == charset_not;
+	/* Address of the place where a forward jump should go to the end of
+	   the containing expression.  Each alternative of an `or' -- except the
+	   last -- ends with a forward jump of this sort.  */
+	unsigned char *fixup_alt_jump = 0;
 
-						if (c < (unsigned char) (p1[4] * BYTEWIDTH)
-							&& p1[5 +
-								  c / BYTEWIDTH] & (1 << (c %
-														  BYTEWIDTH))) not
-								= !not;
+	/* Counts open-groups as they are encountered.  Remembered for the
+	   matching close-group on the compile stack, so the same register
+	   number is put in the stop_memory as the start_memory.  */
+	regnum_t regnum = 0;
 
-						/* `not' is equal to 1 if c would match, which means
-						   that we can't change to pop_failure_jump.  */
-						if (!not) {
-							p[-3] = (unsigned char) pop_failure_jump;
-							DEBUG_PRINT1
-								("  No match => pop_failure_jump.\n");
-						}
-					}
-				} else if ((re_opcode_t) * p2 == charset) {
-					/* We win if the first character of the loop is not part
-					   of the charset.  */
-					if ((re_opcode_t) p1[3] == exactn
-						&& !((int) p2[1] * BYTEWIDTH > (int) p1[5]
-							 && (p2[2 + p1[5] / BYTEWIDTH]
-								 & (1 << (p1[5] % BYTEWIDTH))))) {
-						p[-3] = (unsigned char) pop_failure_jump;
-						DEBUG_PRINT1("  No match => pop_failure_jump.\n");
-					}
+#ifdef DEBUG
+	DEBUG_PRINT1("\nCompiling pattern: ");
+	if (debug) {
+		unsigned debug_count;
 
-					else if ((re_opcode_t) p1[3] == charset_not) {
-						int idx;
+		for (debug_count = 0; debug_count < size; debug_count++)
+			putchar(pattern[debug_count]);
+		putchar('\n');
+	}
+#endif							/* DEBUG */
 
-						/* We win if the charset_not inside the loop
-						   lists every character listed in the charset after.  */
-						for (idx = 0; idx < (int) p2[1]; idx++)
-							if (!(p2[2 + idx] == 0 || (idx < (int) p1[4]
-													   &&
-													   ((p2
-														 [2 +
-														  idx] & ~p1[5 +
-																	 idx])
-														== 0))))
-								break;
+	/* Initialize the compile stack.  */
+	compile_stack.stack =
+		TALLOC(INIT_COMPILE_STACK_SIZE, compile_stack_elt_t);
+	if (compile_stack.stack == NULL)
+		return REG_ESPACE;
 
-						if (idx == p2[1]) {
-							p[-3] = (unsigned char) pop_failure_jump;
-							DEBUG_PRINT1
-								("  No match => pop_failure_jump.\n");
-						}
-					} else if ((re_opcode_t) p1[3] == charset) {
-						int idx;
+	compile_stack.size = INIT_COMPILE_STACK_SIZE;
+	compile_stack.avail = 0;
 
-						/* We win if the charset inside the loop
-						   has no overlap with the one after the loop.  */
-						for (idx = 0;
-							 idx < (int) p2[1] && idx < (int) p1[4]; idx++)
-							if ((p2[2 + idx] & p1[5 + idx]) != 0)
-								break;
+	/* Initialize the pattern buffer.  */
+	bufp->syntax = syntax;
+	bufp->fastmap_accurate = 0;
+	bufp->not_bol = bufp->not_eol = 0;
 
-						if (idx == p2[1] || idx == p1[4]) {
-							p[-3] = (unsigned char) pop_failure_jump;
-							DEBUG_PRINT1
-								("  No match => pop_failure_jump.\n");
-						}
-					}
-				}
-			}
-			p -= 2;				/* Point at relative address again.  */
-			if ((re_opcode_t) p[-1] != pop_failure_jump) {
-				p[-1] = (unsigned char) jump;
-				DEBUG_PRINT1("  Match => jump.\n");
-				goto unconditional_jump;
-			}
-			/* Note fall through.  */
+	/* Set `used' to zero, so that if we return an error, the pattern
+	   printer (for debugging) will think there's no pattern.  We reset it
+	   at the end.  */
+	bufp->used = 0;
 
+	/* Always count groups, whether or not bufp->no_sub is set.  */
+	bufp->re_nsub = 0;
 
-			/* The end of a simple repeat has a pop_failure_jump back to
-			   its matching on_failure_jump, where the latter will push a
-			   failure point.  The pop_failure_jump takes off failure
-			   points put on by this pop_failure_jump's matching
-			   on_failure_jump; we got through the pattern to here from the
-			   matching on_failure_jump, so didn't fail.  */
-		case pop_failure_jump:
-		{
-			/* We need to pass separate storage for the lowest and
-			   highest registers, even though we don't care about the
-			   actual values.  Otherwise, we will restore only one
-			   register from the stack, since lowest will == highest in
-			   `pop_failure_point'.  */
-			active_reg_t dummy_low_reg, dummy_high_reg;
-			unsigned char *pdummy;
-			const char *sdummy;
+#if !defined emacs && !defined SYNTAX_TABLE
+	/* Initialize the syntax table.  */
+	init_syntax_once();
+#endif
 
-			DEBUG_PRINT1("EXECUTING pop_failure_jump.\n");
-			POP_FAILURE_POINT(sdummy, pdummy,
-							  dummy_low_reg, dummy_high_reg,
-							  reg_dummy, reg_dummy, reg_info_dummy);
+	if (bufp->allocated == 0) {
+		if (bufp->buffer) {		/* If zero allocated, but buffer is non-null, try to realloc
+								   enough space.  This loses if buffer's address is bogus, but
+								   that is the user's responsibility.  */
+			RETALLOC(bufp->buffer, INIT_BUF_SIZE, unsigned char);
+		} else {				/* Caller did not allocate a buffer.  Do it for them.  */
+			bufp->buffer = TALLOC(INIT_BUF_SIZE, unsigned char);
 		}
-			/* Note fall through.  */
+		if (!bufp->buffer)
+			FREE_STACK_RETURN(REG_ESPACE);
 
-		  unconditional_jump:
-#ifdef _LIBC
-			DEBUG_PRINT2("\n%p: ", p);
-#else
-			DEBUG_PRINT2("\n0x%x: ", p);
-#endif
-			/* Note fall through.  */
+		bufp->allocated = INIT_BUF_SIZE;
+	}
 
-			/* Unconditionally jump (without popping any failure points).  */
-		case jump:
-			EXTRACT_NUMBER_AND_INCR(mcnt, p);	/* Get the amount to jump.  */
-			DEBUG_PRINT2("EXECUTING jump %d ", mcnt);
-			p += mcnt;			/* Do the jump.  */
-#ifdef _LIBC
-			DEBUG_PRINT2("(to %p).\n", p);
-#else
-			DEBUG_PRINT2("(to 0x%x).\n", p);
-#endif
+	begalt = b = bufp->buffer;
+
+	/* Loop through the uncompiled pattern until we're at the end.  */
+	while (p != pend) {
+		PATFETCH(c);
+
+		switch (c) {
+		case '^':
+		{
+			if (				/* If at start of pattern, it's an operator.  */
+				   p == pattern + 1
+				   /* If context independent, it's an operator.  */
+				   || syntax & RE_CONTEXT_INDEP_ANCHORS
+				   /* Otherwise, depends on what's come before.  */
+				   || at_begline_loc_p(pattern, p, syntax))
+				BUF_PUSH(begline);
+			else
+				goto normal_char;
+		}
 			break;
 
 
-			/* We need this opcode so we can detect where alternatives end
-			   in `group_match_null_string_p' et al.  */
-		case jump_past_alt:
-			DEBUG_PRINT1("EXECUTING jump_past_alt.\n");
-			goto unconditional_jump;
+		case '$':
+		{
+			if (				/* If at end of pattern, it's an operator.  */
+				   p == pend
+				   /* If context independent, it's an operator.  */
+				   || syntax & RE_CONTEXT_INDEP_ANCHORS
+				   /* Otherwise, depends on what's next.  */
+				   || at_endline_loc_p(p, pend, syntax))
+				BUF_PUSH(endline);
+			else
+				goto normal_char;
+		}
+			break;
 
 
-			/* Normally, the on_failure_jump pushes a failure point, which
-			   then gets popped at pop_failure_jump.  We will end up at
-			   pop_failure_jump, also, and with a pattern of, say, `a+', we
-			   are skipping over the on_failure_jump, so we have to push
-			   something meaningless for pop_failure_jump to pop.  */
-		case dummy_failure_jump:
-			DEBUG_PRINT1("EXECUTING dummy_failure_jump.\n");
-			/* It doesn't matter what we push for the string here.  What
-			   the code at `fail' tests is the value for the pattern.  */
-			PUSH_FAILURE_POINT(NULL, NULL, -2);
-			goto unconditional_jump;
+		case '+':
+		case '?':
+			if ((syntax & RE_BK_PLUS_QM)
+				|| (syntax & RE_LIMITED_OPS))
+				goto normal_char;
+		  handle_plus:
+		case '*':
+			/* If there is no previous pattern... */
+			if (!laststart) {
+				if (syntax & RE_CONTEXT_INVALID_OPS)
+					FREE_STACK_RETURN(REG_BADRPT);
+				else if (!(syntax & RE_CONTEXT_INDEP_OPS))
+					goto normal_char;
+			}
 
+			{
+				/* Are we optimizing this jump?  */
+				boolean keep_string_p = false;
 
-			/* At the end of an alternative, we need to push a dummy failure
-			   point in case we are followed by a `pop_failure_jump', because
-			   we don't want the failure point for the alternative to be
-			   popped.  For example, matching `(a|ab)*' against `aab'
-			   requires that we match the `ab' alternative.  */
-		case push_dummy_failure:
-			DEBUG_PRINT1("EXECUTING push_dummy_failure.\n");
-			/* See comments just above at `dummy_failure_jump' about the
-			   two zeroes.  */
-			PUSH_FAILURE_POINT(NULL, NULL, -2);
-			break;
+				/* 1 means zero (many) matches is allowed.  */
+				char zero_times_ok = 0, many_times_ok = 0;
 
-			/* Have to succeed matching what follows at least n times.
-			   After that, handle like `on_failure_jump'.  */
-		case succeed_n:
-			EXTRACT_NUMBER(mcnt, p + 2);
-			DEBUG_PRINT2("EXECUTING succeed_n %d.\n", mcnt);
+				/* If there is a sequence of repetition chars, collapse it
+				   down to just one (the right one).  We can't combine
+				   interval operators with these because of, e.g., `a{2}*',
+				   which should only match an even number of `a's.  */
 
-			assert(mcnt >= 0);
-			/* Originally, this is how many times we HAVE to succeed.  */
-			if (mcnt > 0) {
-				mcnt--;
-				p += 2;
-				STORE_NUMBER_AND_INCR(p, mcnt);
-#ifdef _LIBC
-				DEBUG_PRINT3("  Setting %p to %d.\n", p - 2, mcnt);
-#else
-				DEBUG_PRINT3("  Setting 0x%x to %d.\n", p - 2, mcnt);
-#endif
-			} else if (mcnt == 0) {
-#ifdef _LIBC
-				DEBUG_PRINT2("  Setting two bytes from %p to no_op.\n",
-							 p + 2);
-#else
-				DEBUG_PRINT2("  Setting two bytes from 0x%x to no_op.\n",
-							 p + 2);
-#endif
-				p[2] = (unsigned char) no_op;
-				p[3] = (unsigned char) no_op;
-				goto on_failure;
-			}
-			break;
+				for (;;) {
+					zero_times_ok |= c != '+';
+					many_times_ok |= c != '?';
 
-		case jump_n:
-			EXTRACT_NUMBER(mcnt, p + 2);
-			DEBUG_PRINT2("EXECUTING jump_n %d.\n", mcnt);
+					if (p == pend)
+						break;
 
-			/* Originally, this is how many times we CAN jump.  */
-			if (mcnt) {
-				mcnt--;
-				STORE_NUMBER(p + 2, mcnt);
-#ifdef _LIBC
-				DEBUG_PRINT3("  Setting %p to %d.\n", p + 2, mcnt);
-#else
-				DEBUG_PRINT3("  Setting 0x%x to %d.\n", p + 2, mcnt);
-#endif
-				goto unconditional_jump;
-			}
-			/* If don't have to jump any more, skip over the rest of command.  */
-			else
-				p += 4;
-			break;
+					PATFETCH(c);
 
-		case set_number_at:
-		{
-			DEBUG_PRINT1("EXECUTING set_number_at.\n");
+					if (c == '*'
+						|| (!(syntax & RE_BK_PLUS_QM)
+							&& (c == '+' || c == '?')));
 
-			EXTRACT_NUMBER_AND_INCR(mcnt, p);
-			p1 = p + mcnt;
-			EXTRACT_NUMBER_AND_INCR(mcnt, p);
-#ifdef _LIBC
-			DEBUG_PRINT3("  Setting %p to %d.\n", p1, mcnt);
-#else
-			DEBUG_PRINT3("  Setting 0x%x to %d.\n", p1, mcnt);
-#endif
-			STORE_NUMBER(p1, mcnt);
-			break;
-		}
+					else if (syntax & RE_BK_PLUS_QM && c == '\\') {
+						if (p == pend)
+							FREE_STACK_RETURN(REG_EESCAPE);
 
-#if 0
-			/* The DEC Alpha C compiler 3.x generates incorrect code for the
-			   test  WORDCHAR_P (d - 1) != WORDCHAR_P (d)  in the expansion of
-			   AT_WORD_BOUNDARY, so this code is disabled.  Expanding the
-			   macro and introducing temporary variables works around the bug.  */
+						PATFETCH(c1);
+						if (!(c1 == '+' || c1 == '?')) {
+							PATUNFETCH;
+							PATUNFETCH;
+							break;
+						}
 
-		case wordbound:
-			DEBUG_PRINT1("EXECUTING wordbound.\n");
-			if (AT_WORD_BOUNDARY(d))
-				break;
-			goto fail;
+						c = c1;
+					} else {
+						PATUNFETCH;
+						break;
+					}
 
-		case notwordbound:
-			DEBUG_PRINT1("EXECUTING notwordbound.\n");
-			if (AT_WORD_BOUNDARY(d))
-				goto fail;
-			break;
-#else
-		case wordbound:
-		{
-			boolean prevchar, thischar;
+					/* If we get here, we found another repeat character.  */
+				}
 
-			DEBUG_PRINT1("EXECUTING wordbound.\n");
-			if (AT_STRINGS_BEG(d) || AT_STRINGS_END(d))
-				break;
+				/* Star, etc. applied to an empty pattern is equivalent
+				   to an empty pattern.  */
+				if (!laststart)
+					break;
 
-			prevchar = WORDCHAR_P(d - 1);
-			thischar = WORDCHAR_P(d);
-			if (prevchar != thischar)
-				break;
-			goto fail;
-		}
+				/* Now we know whether or not zero matches is allowed
+				   and also whether or not two or more matches is allowed.  */
+				if (many_times_ok) {	/* More than one repetition is allowed, so put in at the
+										   end a backward relative jump from `b' to before the next
+										   jump we're going to put in below (which jumps from
+										   laststart to after this jump).
 
-		case notwordbound:
-		{
-			boolean prevchar, thischar;
+										   But if we are at the `*' in the exact sequence `.*\n',
+										   insert an unconditional jump backwards to the .,
+										   instead of the beginning of the loop.  This way we only
+										   push a failure point once, instead of every time
+										   through the loop.  */
+					assert(p - 1 > pattern);
 
-			DEBUG_PRINT1("EXECUTING notwordbound.\n");
-			if (AT_STRINGS_BEG(d) || AT_STRINGS_END(d))
-				goto fail;
+					/* Allocate the space for the jump.  */
+					GET_BUFFER_SPACE(3);
 
-			prevchar = WORDCHAR_P(d - 1);
-			thischar = WORDCHAR_P(d);
-			if (prevchar != thischar)
-				goto fail;
-			break;
-		}
-#endif
+					/* We know we are not at the first character of the pattern,
+					   because laststart was nonzero.  And we've already
+					   incremented `p', by the way, to be the character after
+					   the `*'.  Do we have to do something analogous here
+					   for null bytes, because of RE_DOT_NOT_NULL?  */
+					if (TRANSLATE(*(p - 2)) == TRANSLATE('.')
+						&& zero_times_ok
+						&& p < pend && TRANSLATE(*p) == TRANSLATE('\n')
+						&& !(syntax & RE_DOT_NEWLINE)) {	/* We have .*\n.  */
+						STORE_JUMP(jump, b, laststart);
+						keep_string_p = true;
+					} else
+						/* Anything else.  */
+						STORE_JUMP(maybe_pop_jump, b, laststart - 3);
 
-		case wordbeg:
-			DEBUG_PRINT1("EXECUTING wordbeg.\n");
-			if (WORDCHAR_P(d) && (AT_STRINGS_BEG(d) || !WORDCHAR_P(d - 1)))
-				break;
-			goto fail;
+					/* We've added more stuff to the buffer.  */
+					b += 3;
+				}
 
-		case wordend:
-			DEBUG_PRINT1("EXECUTING wordend.\n");
-			if (!AT_STRINGS_BEG(d) && WORDCHAR_P(d - 1)
-				&& (!WORDCHAR_P(d) || AT_STRINGS_END(d)))
-				break;
-			goto fail;
+				/* On failure, jump from laststart to b + 3, which will be the
+				   end of the buffer after this jump is inserted.  */
+				GET_BUFFER_SPACE(3);
+				INSERT_JUMP(keep_string_p ? on_failure_keep_string_jump
+							: on_failure_jump, laststart, b + 3);
+				pending_exact = 0;
+				b += 3;
 
-#ifdef emacs
-		case before_dot:
-			DEBUG_PRINT1("EXECUTING before_dot.\n");
-			if (PTR_CHAR_POS((unsigned char *) d) >= point)
-				goto fail;
+				if (!zero_times_ok) {
+					/* At least one repetition is required, so insert a
+					   `dummy_failure_jump' before the initial
+					   `on_failure_jump' instruction of the loop. This
+					   effects a skip over that instruction the first time
+					   we hit that loop.  */
+					GET_BUFFER_SPACE(3);
+					INSERT_JUMP(dummy_failure_jump, laststart,
+								laststart + 6);
+					b += 3;
+				}
+			}
 			break;
 
-		case at_dot:
-			DEBUG_PRINT1("EXECUTING at_dot.\n");
-			if (PTR_CHAR_POS((unsigned char *) d) != point)
-				goto fail;
-			break;
 
-		case after_dot:
-			DEBUG_PRINT1("EXECUTING after_dot.\n");
-			if (PTR_CHAR_POS((unsigned char *) d) <= point)
-				goto fail;
+		case '.':
+			laststart = b;
+			BUF_PUSH(anychar);
 			break;
 
-		case syntaxspec:
-			DEBUG_PRINT2("EXECUTING syntaxspec %d.\n", mcnt);
-			mcnt = *p++;
-			goto matchsyntax;
 
-		case wordchar:
-			DEBUG_PRINT1("EXECUTING Emacs wordchar.\n");
-			mcnt = (int) Sword;
-		  matchsyntax:
-			PREFETCH();
-			/* Can't use *d++ here; SYNTAX may be an unsafe macro.  */
-			d++;
-			if (SYNTAX(d[-1]) != (enum syntaxcode) mcnt)
-				goto fail;
-			SET_REGS_MATCHED();
-			break;
+		case '[':
+		{
+			boolean had_char_class = false;
 
-		case notsyntaxspec:
-			DEBUG_PRINT2("EXECUTING notsyntaxspec %d.\n", mcnt);
-			mcnt = *p++;
-			goto matchnotsyntax;
+			if (p == pend)
+				FREE_STACK_RETURN(REG_EBRACK);
 
-		case notwordchar:
-			DEBUG_PRINT1("EXECUTING Emacs notwordchar.\n");
-			mcnt = (int) Sword;
-		  matchnotsyntax:
-			PREFETCH();
-			/* Can't use *d++ here; SYNTAX may be an unsafe macro.  */
-			d++;
-			if (SYNTAX(d[-1]) == (enum syntaxcode) mcnt)
-				goto fail;
-			SET_REGS_MATCHED();
-			break;
+			/* Ensure that we have enough space to push a charset: the
+			   opcode, the length count, and the bitset; 34 bytes in all.  */
+			GET_BUFFER_SPACE(34);
 
-#else							/* not emacs */
-		case wordchar:
-			DEBUG_PRINT1("EXECUTING non-Emacs wordchar.\n");
-			PREFETCH();
-			if (!WORDCHAR_P(d))
-				goto fail;
-			SET_REGS_MATCHED();
-			d++;
-			break;
+			laststart = b;
 
-		case notwordchar:
-			DEBUG_PRINT1("EXECUTING non-Emacs notwordchar.\n");
-			PREFETCH();
-			if (WORDCHAR_P(d))
-				goto fail;
-			SET_REGS_MATCHED();
-			d++;
-			break;
-#endif							/* not emacs */
+			/* We test `*p == '^' twice, instead of using an if
+			   statement, so we only need one BUF_PUSH.  */
+			BUF_PUSH(*p == '^' ? charset_not : charset);
+			if (*p == '^')
+				p++;
 
-		default:
-			abort();
-		}
-		continue;				/* Successfully executed one pattern command; keep going.  */
+			/* Remember the first position in the bracket expression.  */
+			p1 = p;
 
+			/* Push the number of bytes in the bitmap.  */
+			BUF_PUSH((1 << BYTEWIDTH) / BYTEWIDTH);
 
-		/* We goto here if a matching operation fails. */
-	  fail:
-		if (!FAIL_STACK_EMPTY()) {	/* A restart point is known.  Restore to that state.  */
-			DEBUG_PRINT1("\nFAIL:\n");
-			POP_FAILURE_POINT(d, p,
-							  lowest_active_reg, highest_active_reg,
-							  regstart, regend, reg_info);
+			/* Clear the whole map.  */
+			bzero(b, (1 << BYTEWIDTH) / BYTEWIDTH);
 
-			/* If this failure point is a dummy, try the next one.  */
-			if (!p)
-				goto fail;
+			/* charset_not matches newline according to a syntax bit.  */
+			if ((re_opcode_t) b[-2] == charset_not
+				&& (syntax & RE_HAT_LISTS_NOT_NEWLINE)) SET_LIST_BIT('\n');
 
-			/* If we failed to the end of the pattern, don't examine *p.  */
-			assert(p <= pend);
-			if (p < pend) {
-				boolean is_a_jump_n = false;
+			/* Read in characters and ranges, setting map bits.  */
+			for (;;) {
+				if (p == pend)
+					FREE_STACK_RETURN(REG_EBRACK);
 
-				/* If failed to a backwards jump that's part of a repetition
-				   loop, need to pop this failure point and use the next one.  */
-				switch ((re_opcode_t) * p) {
-				case jump_n:
-					is_a_jump_n = true;
-				case maybe_pop_jump:
-				case pop_failure_jump:
-				case jump:
-					p1 = p + 1;
-					EXTRACT_NUMBER_AND_INCR(mcnt, p1);
-					p1 += mcnt;
+				PATFETCH(c);
 
-					if ((is_a_jump_n && (re_opcode_t) * p1 == succeed_n)
-						|| (!is_a_jump_n
-							&& (re_opcode_t) * p1 == on_failure_jump))
-							goto fail;
-					break;
-				default:
-					/* do nothing */ ;
-				}
-			}
+				/* \ might escape characters inside [...] and [^...].  */
+				if ((syntax & RE_BACKSLASH_ESCAPE_IN_LISTS) && c == '\\') {
+					if (p == pend)
+						FREE_STACK_RETURN(REG_EESCAPE);
 
-			if (d >= string1 && d <= end1)
-				dend = end_match_1;
-		} else
-			break;				/* Matching at this starting point really fails.  */
-	}							/* for (;;) */
+					PATFETCH(c1);
+					SET_LIST_BIT(c1);
+					continue;
+				}
 
-	if (best_regs_set)
-		goto restore_best_regs;
+				/* Could be the end of the bracket expression.  If it's
+				   not (i.e., when the bracket expression is `[]' so
+				   far), the ']' character bit gets set way below.  */
+				if (c == ']' && p != p1 + 1)
+					break;
 
-	FREE_VARIABLES();
+				/* Look ahead to see if it's a range when the last thing
+				   was a character class.  */
+				if (had_char_class && c == '-' && *p != ']')
+					FREE_STACK_RETURN(REG_ERANGE);
 
-	return -1;					/* Failure to match.  */
-}								/* re_match_2 */
-
-/* Subroutine definitions for re_match_2.  */
+				/* Look ahead to see if it's a range when the last thing
+				   was a character: if this is a hyphen not at the
+				   beginning or the end of a list, then it's the range
+				   operator.  */
+				if (c == '-' && !(p - 2 >= pattern && p[-2] == '[')
+					&& !(p - 3 >= pattern && p[-3] == '[' && p[-2] == '^')
+					&& *p != ']') {
+					reg_errcode_t ret
+						= compile_range(&p, pend, translate, syntax, b);
 
+					if (ret != REG_NOERROR)
+						FREE_STACK_RETURN(ret);
+				}
 
-/* We are passed P pointing to a register number after a start_memory.
+				else if (p[0] == '-' && p[1] != ']') {	/* This handles ranges made up of characters only.  */
+					reg_errcode_t ret;
 
-   Return true if the pattern up to the corresponding stop_memory can
-   match the empty string, and false otherwise.
+					/* Move past the `-'.  */
+					PATFETCH(c1);
 
-   If we find the matching stop_memory, sets P to point to one past its number.
-   Otherwise, sets P to an undefined byte less than or equal to END.
+					ret = compile_range(&p, pend, translate, syntax, b);
+					if (ret != REG_NOERROR)
+						FREE_STACK_RETURN(ret);
+				}
 
-   We don't handle duplicates properly (yet).  */
+				/* See if we're at the beginning of a possible character
+				   class.  */
 
-static boolean group_match_null_string_p(p, end, reg_info)
-unsigned char **p, *end;
-register_info_type *reg_info;
-{
-	int mcnt;
+				else if (syntax & RE_CHAR_CLASSES && c == '[' && *p == ':') {	/* Leave room for the null.  */
+					char str[CHAR_CLASS_MAX_LENGTH + 1];
 
-	/* Point to after the args to the start_memory.  */
-	unsigned char *p1 = *p + 2;
+					PATFETCH(c);
+					c1 = 0;
 
-	while (p1 < end) {
-		/* Skip over opcodes that can match nothing, and return true or
-		   false, as appropriate, when we get to one that can't, or to the
-		   matching stop_memory.  */
+					/* If pattern is `[[:'.  */
+					if (p == pend)
+						FREE_STACK_RETURN(REG_EBRACK);
 
-		switch ((re_opcode_t) * p1) {
-			/* Could be either a loop or a series of alternatives.  */
-		case on_failure_jump:
-			p1++;
-			EXTRACT_NUMBER_AND_INCR(mcnt, p1);
+					for (;;) {
+						PATFETCH(c);
+						if ((c == ':' && *p == ']') || p == pend)
+							break;
+						if (c1 < CHAR_CLASS_MAX_LENGTH)
+							str[c1++] = c;
+						else
+							/* This is in any case an invalid class name.  */
+							str[0] = '\0';
+					}
+					str[c1] = '\0';
 
-			/* If the next operation is not a jump backwards in the
-			   pattern.  */
+					/* If isn't a word bracketed by `[:' and `:]':
+					   undo the ending character, the letters, and leave
+					   the leading `:' and `[' (but set bits for them).  */
+					if (c == ':' && *p == ']') {
+#if defined _LIBC || WIDE_CHAR_SUPPORT
+						boolean is_lower = STREQ(str, "lower");
+						boolean is_upper = STREQ(str, "upper");
+						wctype_t wt;
+						int ch;
 
-			if (mcnt >= 0) {
-				/* Go through the on_failure_jumps of the alternatives,
-				   seeing if any of the alternatives cannot match nothing.
-				   The last alternative starts with only a jump,
-				   whereas the rest start with on_failure_jump and end
-				   with a jump, e.g., here is the pattern for `a|b|c':
+						wt = IS_CHAR_CLASS(str);
+						if (wt == 0)
+							FREE_STACK_RETURN(REG_ECTYPE);
 
-				   /on_failure_jump/0/6/exactn/1/a/jump_past_alt/0/6
-				   /on_failure_jump/0/6/exactn/1/b/jump_past_alt/0/3
-				   /exactn/1/c
+						/* Throw away the ] at the end of the character
+						   class.  */
+						PATFETCH(c);
 
-				   So, we have to first go through the first (n-1)
-				   alternatives and then deal with the last one separately.  */
+						if (p == pend)
+							FREE_STACK_RETURN(REG_EBRACK);
 
+						for (ch = 0; ch < 1 << BYTEWIDTH; ++ch) {
+# ifdef _LIBC
+							if (__iswctype(__btowc(ch), wt))
+								SET_LIST_BIT(ch);
+# else
+							if (iswctype(btowc(ch), wt))
+								SET_LIST_BIT(ch);
+# endif
 
-				/* Deal with the first (n-1) alternatives, which start
-				   with an on_failure_jump (see above) that jumps to right
-				   past a jump_past_alt.  */
+							if (translate && (is_upper || is_lower)
+								&& (ISUPPER(ch) || ISLOWER(ch)))
+								SET_LIST_BIT(ch);
+						}
 
-				while ((re_opcode_t) p1[mcnt - 3] == jump_past_alt) {
-					/* `mcnt' holds how many bytes long the alternative
-					   is, including the ending `jump_past_alt' and
-					   its number.  */
+						had_char_class = true;
+#else
+						int ch;
+						boolean is_alnum = STREQ(str, "alnum");
+						boolean is_alpha = STREQ(str, "alpha");
+						boolean is_blank = STREQ(str, "blank");
+						boolean is_cntrl = STREQ(str, "cntrl");
+						boolean is_digit = STREQ(str, "digit");
+						boolean is_graph = STREQ(str, "graph");
+						boolean is_lower = STREQ(str, "lower");
+						boolean is_print = STREQ(str, "print");
+						boolean is_punct = STREQ(str, "punct");
+						boolean is_space = STREQ(str, "space");
+						boolean is_upper = STREQ(str, "upper");
+						boolean is_xdigit = STREQ(str, "xdigit");
 
-					if (!alt_match_null_string_p(p1, p1 + mcnt - 3,
-												 reg_info)) return false;
+						if (!IS_CHAR_CLASS(str))
+							FREE_STACK_RETURN(REG_ECTYPE);
 
-					/* Move to right after this alternative, including the
-					   jump_past_alt.  */
-					p1 += mcnt;
+						/* Throw away the ] at the end of the character
+						   class.  */
+						PATFETCH(c);
 
-					/* Break if it's the beginning of an n-th alternative
-					   that doesn't begin with an on_failure_jump.  */
-					if ((re_opcode_t) * p1 != on_failure_jump)
-						break;
+						if (p == pend)
+							FREE_STACK_RETURN(REG_EBRACK);
 
-					/* Still have to check that it's not an n-th
-					   alternative that starts with an on_failure_jump.  */
-					p1++;
-					EXTRACT_NUMBER_AND_INCR(mcnt, p1);
-					if ((re_opcode_t) p1[mcnt - 3] != jump_past_alt) {
-						/* Get to the beginning of the n-th alternative.  */
-						p1 -= 3;
-						break;
+						for (ch = 0; ch < 1 << BYTEWIDTH; ch++) {
+							/* This was split into 3 if's to
+							   avoid an arbitrary limit in some compiler.  */
+							if ((is_alnum && ISALNUM(ch))
+								|| (is_alpha && ISALPHA(ch))
+								|| (is_blank && ISBLANK(ch))
+								|| (is_cntrl && ISCNTRL(ch)))
+								SET_LIST_BIT(ch);
+							if ((is_digit && ISDIGIT(ch))
+								|| (is_graph && ISGRAPH(ch))
+								|| (is_lower && ISLOWER(ch))
+								|| (is_print && ISPRINT(ch)))
+								SET_LIST_BIT(ch);
+							if ((is_punct && ISPUNCT(ch))
+								|| (is_space && ISSPACE(ch))
+								|| (is_upper && ISUPPER(ch))
+								|| (is_xdigit && ISXDIGIT(ch)))
+								SET_LIST_BIT(ch);
+							if (translate && (is_upper || is_lower)
+								&& (ISUPPER(ch) || ISLOWER(ch)))
+								SET_LIST_BIT(ch);
+						}
+						had_char_class = true;
+#endif							/* libc || wctype.h */
+					} else {
+						c1++;
+						while (c1--)
+							PATUNFETCH;
+						SET_LIST_BIT('[');
+						SET_LIST_BIT(':');
+						had_char_class = false;
 					}
+				} else {
+					had_char_class = false;
+					SET_LIST_BIT(c);
 				}
+			}
 
-				/* Deal with the last alternative: go back and get number
-				   of the `jump_past_alt' just before it.  `mcnt' contains
-				   the length of the alternative.  */
-				EXTRACT_NUMBER(mcnt, p1 - 2);
+			/* Discard any (non)matching list bytes that are all 0 at the
+			   end of the map.  Decrease the map-length byte too.  */
+			while ((int) b[-1] > 0 && b[b[-1] - 1] == 0)
+				b[-1]--;
+			b += b[-1];
+		}
+			break;
 
-				if (!alt_match_null_string_p(p1, p1 + mcnt, reg_info))
-					return false;
 
-				p1 += mcnt;		/* Get past the n-th alternative.  */
-			}					/* if mcnt > 0 */
-			break;
+		case '(':
+			if (syntax & RE_NO_BK_PARENS)
+				goto handle_open;
+			else
+				goto normal_char;
 
 
-		case stop_memory:
-			assert(p1[1] == **p);
-			*p = p1 + 2;
-			return true;
+		case ')':
+			if (syntax & RE_NO_BK_PARENS)
+				goto handle_close;
+			else
+				goto normal_char;
 
 
-		default:
-			if (!common_op_match_null_string_p(&p1, end, reg_info))
-				return false;
-		}
-	}							/* while p1 < end */
+		case '\n':
+			if (syntax & RE_NEWLINE_ALT)
+				goto handle_alt;
+			else
+				goto normal_char;
 
-	return false;
-}								/* group_match_null_string_p */
 
+		case '|':
+			if (syntax & RE_NO_BK_VBAR)
+				goto handle_alt;
+			else
+				goto normal_char;
 
-/* Similar to group_match_null_string_p, but doesn't deal with alternatives:
-   It expects P to be the first byte of a single alternative and END one
-   byte past the last. The alternative can contain groups.  */
 
-static boolean alt_match_null_string_p(p, end, reg_info)
-unsigned char *p, *end;
-register_info_type *reg_info;
-{
-	int mcnt;
-	unsigned char *p1 = p;
+		case '{':
+			if (syntax & RE_INTERVALS && syntax & RE_NO_BK_BRACES)
+				goto handle_interval;
+			else
+				goto normal_char;
 
-	while (p1 < end) {
-		/* Skip over opcodes that can match nothing, and break when we get
-		   to one that can't.  */
 
-		switch ((re_opcode_t) * p1) {
-			/* It's a loop.  */
-		case on_failure_jump:
-			p1++;
-			EXTRACT_NUMBER_AND_INCR(mcnt, p1);
-			p1 += mcnt;
-			break;
+		case '\\':
+			if (p == pend)
+				FREE_STACK_RETURN(REG_EESCAPE);
 
-		default:
-			if (!common_op_match_null_string_p(&p1, end, reg_info))
-				return false;
-		}
-	}							/* while p1 < end */
+			/* Do not translate the character after the \, so that we can
+			   distinguish, e.g., \B from \b, even if we normally would
+			   translate, e.g., B to b.  */
+			PATFETCH_RAW(c);
 
-	return true;
-}								/* alt_match_null_string_p */
+			switch (c) {
+			case '(':
+				if (syntax & RE_NO_BK_PARENS)
+					goto normal_backslash;
 
+			  handle_open:
+				bufp->re_nsub++;
+				regnum++;
 
-/* Deals with the ops common to group_match_null_string_p and
-   alt_match_null_string_p.
+				if (COMPILE_STACK_FULL) {
+					RETALLOC(compile_stack.stack, compile_stack.size << 1,
+							 compile_stack_elt_t);
+					if (compile_stack.stack == NULL)
+						return REG_ESPACE;
 
-   Sets P to one after the op and its arguments, if any.  */
+					compile_stack.size <<= 1;
+				}
 
-static boolean common_op_match_null_string_p(p, end, reg_info)
-unsigned char **p, *end;
-register_info_type *reg_info;
-{
-	int mcnt;
-	boolean ret;
-	int reg_no;
-	unsigned char *p1 = *p;
+				/* These are the values to restore when we hit end of this
+				   group.  They are all relative offsets, so that if the
+				   whole pattern moves because of realloc, they will still
+				   be valid.  */
+				COMPILE_STACK_TOP.begalt_offset = begalt - bufp->buffer;
+				COMPILE_STACK_TOP.fixup_alt_jump
+					=
+					fixup_alt_jump ? fixup_alt_jump - bufp->buffer + 1 : 0;
+				COMPILE_STACK_TOP.laststart_offset = b - bufp->buffer;
+				COMPILE_STACK_TOP.regnum = regnum;
 
-	switch ((re_opcode_t) * p1++) {
-	case no_op:
-	case begline:
-	case endline:
-	case begbuf:
-	case endbuf:
-	case wordbeg:
-	case wordend:
-	case wordbound:
-	case notwordbound:
-#ifdef emacs
-	case before_dot:
-	case at_dot:
-	case after_dot:
-#endif
-		break;
+				/* We will eventually replace the 0 with the number of
+				   groups inner to this one.  But do not push a
+				   start_memory for groups beyond the last one we can
+				   represent in the compiled pattern.  */
+				if (regnum <= MAX_REGNUM) {
+					COMPILE_STACK_TOP.inner_group_offset =
+						b - bufp->buffer + 2;
+					BUF_PUSH_3(start_memory, regnum, 0);
+				}
 
-	case start_memory:
-		reg_no = *p1;
-		assert(reg_no > 0 && reg_no <= MAX_REGNUM);
-		ret = group_match_null_string_p(&p1, end, reg_info);
+				compile_stack.avail++;
 
-		/* Have to set this here in case we're checking a group which
-		   contains a group and a back reference to it.  */
+				fixup_alt_jump = 0;
+				laststart = 0;
+				begalt = b;
+				/* If we've reached MAX_REGNUM groups, then this open
+				   won't actually generate any code, so we'll have to
+				   clear pending_exact explicitly.  */
+				pending_exact = 0;
+				break;
 
-		if (REG_MATCH_NULL_STRING_P(reg_info[reg_no]) ==
-			MATCH_NULL_UNSET_VALUE)
-				REG_MATCH_NULL_STRING_P(reg_info[reg_no]) = ret;
 
-		if (!ret)
-			return false;
-		break;
+			case ')':
+				if (syntax & RE_NO_BK_PARENS)
+					goto normal_backslash;
 
-		/* If this is an optimized succeed_n for zero times, make the jump.  */
-	case jump:
-		EXTRACT_NUMBER_AND_INCR(mcnt, p1);
-		if (mcnt >= 0)
-			p1 += mcnt;
-		else
-			return false;
-		break;
+				if (COMPILE_STACK_EMPTY) {
+					if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
+						goto normal_backslash;
+					else
+						FREE_STACK_RETURN(REG_ERPAREN);
+				}
 
-	case succeed_n:
-		/* Get to the number of times to succeed.  */
-		p1 += 2;
-		EXTRACT_NUMBER_AND_INCR(mcnt, p1);
+			  handle_close:
+				if (fixup_alt_jump) {	/* Push a dummy failure point at the end of the
+										   alternative for a possible future
+										   `pop_failure_jump' to pop.  See comments at
+										   `push_dummy_failure' in `re_match_2'.  */
+					BUF_PUSH(push_dummy_failure);
 
-		if (mcnt == 0) {
-			p1 -= 4;
-			EXTRACT_NUMBER_AND_INCR(mcnt, p1);
-			p1 += mcnt;
-		} else
-			return false;
-		break;
+					/* We allocated space for this jump when we assigned
+					   to `fixup_alt_jump', in the `handle_alt' case below.  */
+					STORE_JUMP(jump_past_alt, fixup_alt_jump, b - 1);
+				}
 
-	case duplicate:
-		if (!REG_MATCH_NULL_STRING_P(reg_info[*p1]))
-			return false;
-		break;
+				/* See similar code for backslashed left paren above.  */
+				if (COMPILE_STACK_EMPTY) {
+					if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
+						goto normal_char;
+					else
+						FREE_STACK_RETURN(REG_ERPAREN);
+				}
 
-	case set_number_at:
-		p1 += 4;
+				/* Since we just checked for an empty stack above, this
+				   ``can't happen''.  */
+				assert(compile_stack.avail != 0);
+				{
+					/* We don't just want to restore into `regnum', because
+					   later groups should continue to be numbered higher,
+					   as in `(ab)c(de)' -- the second group is #2.  */
+					regnum_t this_group_regnum;
 
-	default:
-		/* All other opcodes mean we cannot match the empty string.  */
-		return false;
-	}
+					compile_stack.avail--;
+					begalt =
+						bufp->buffer + COMPILE_STACK_TOP.begalt_offset;
+					fixup_alt_jump =
+						COMPILE_STACK_TOP.fixup_alt_jump ? bufp->buffer +
+						COMPILE_STACK_TOP.fixup_alt_jump - 1 : 0;
+					laststart =
+						bufp->buffer + COMPILE_STACK_TOP.laststart_offset;
+					this_group_regnum = COMPILE_STACK_TOP.regnum;
+					/* If we've reached MAX_REGNUM groups, then this open
+					   won't actually generate any code, so we'll have to
+					   clear pending_exact explicitly.  */
+					pending_exact = 0;
 
-	*p = p1;
-	return true;
-}								/* common_op_match_null_string_p */
+					/* We're at the end of the group, so now we know how many
+					   groups were inside this one.  */
+					if (this_group_regnum <= MAX_REGNUM) {
+						unsigned char *inner_group_loc
 
+							=
+							bufp->buffer +
+							COMPILE_STACK_TOP.inner_group_offset;
 
-/* Return zero if TRANSLATE[S1] and TRANSLATE[S2] are identical for LEN
-   bytes; nonzero otherwise.  */
+						*inner_group_loc = regnum - this_group_regnum;
+						BUF_PUSH_3(stop_memory, this_group_regnum,
+								   regnum - this_group_regnum);
+					}
+				}
+				break;
 
-static int bcmp_translate(s1, s2, len, translate)
-const char *s1, *s2;
-register int len;
-RE_TRANSLATE_TYPE translate;
-{
-	register const unsigned char *p1 = (const unsigned char *) s1;
-	register const unsigned char *p2 = (const unsigned char *) s2;
 
-	while (len) {
-		if (translate[*p1++] != translate[*p2++])
-			return 1;
-		len--;
-	}
-	return 0;
-}
-
-/* Entry points for GNU code.  */
+			case '|':			/* `\|'.  */
+				if (syntax & RE_LIMITED_OPS || syntax & RE_NO_BK_VBAR)
+					goto normal_backslash;
+			  handle_alt:
+				if (syntax & RE_LIMITED_OPS)
+					goto normal_char;
 
-/* re_compile_pattern is the GNU regular expression compiler: it
-   compiles PATTERN (of length SIZE) and puts the result in BUFP.
-   Returns 0 if the pattern was valid, otherwise an error string.
+				/* Insert before the previous alternative a jump which
+				   jumps to this alternative if the former fails.  */
+				GET_BUFFER_SPACE(3);
+				INSERT_JUMP(on_failure_jump, begalt, b + 6);
+				pending_exact = 0;
+				b += 3;
 
-   Assumes the `allocated' (and perhaps `buffer') and `translate' fields
-   are set in BUFP on entry.
+				/* The alternative before this one has a jump after it
+				   which gets executed if it gets matched.  Adjust that
+				   jump so it will jump to this alternative's analogous
+				   jump (put in below, which in turn will jump to the next
+				   (if any) alternative's such jump, etc.).  The last such
+				   jump jumps to the correct final destination.  A picture:
+				   _____ _____
+				   |   | |   |
+				   |   v |   v
+				   a | b   | c
 
-   We call regex_compile to do the actual compilation.  */
+				   If we are at `b', then fixup_alt_jump right now points to a
+				   three-byte space after `a'.  We'll put in the jump, set
+				   fixup_alt_jump to right after `b', and leave behind three
+				   bytes which we'll fill in when we get to after `c'.  */
 
-const char *re_compile_pattern(pattern, length, bufp)
-const char *pattern;
-size_t length;
-struct re_pattern_buffer *bufp;
-{
-	reg_errcode_t ret;
+				if (fixup_alt_jump)
+					STORE_JUMP(jump_past_alt, fixup_alt_jump, b);
 
-	/* GNU code is written to assume at least RE_NREGS registers will be set
-	   (and at least one extra will be -1).  */
-	bufp->regs_allocated = REGS_UNALLOCATED;
+				/* Mark and leave space for a jump after this alternative,
+				   to be filled in later either by next alternative or
+				   when know we're at the end of a series of alternatives.  */
+				fixup_alt_jump = b;
+				GET_BUFFER_SPACE(3);
+				b += 3;
 
-	/* And GNU code determines whether or not to get register information
-	   by passing null for the REGS argument to re_match, etc., not by
-	   setting no_sub.  */
-	bufp->no_sub = 0;
+				laststart = 0;
+				begalt = b;
+				break;
 
-	/* Match anchors at newline.  */
-	bufp->newline_anchor = 1;
 
-	ret = regex_compile(pattern, length, re_syntax_options, bufp);
+			case '{':
+				/* If \{ is a literal.  */
+				if (!(syntax & RE_INTERVALS)
+					/* If we're at `\{' and it's not the open-interval
+					   operator.  */
+					|| ((syntax & RE_INTERVALS)
+						&& (syntax & RE_NO_BK_BRACES)) || (p - 2 == pattern
+														   && p == pend))
+					goto normal_backslash;
 
-	if (!ret)
-		return NULL;
-	return gettext(re_error_msgid + re_error_msgid_idx[(int) ret]);
-}
+			  handle_interval:
+				{
+					/* If got here, then the syntax allows intervals.  */
 
-#ifdef _LIBC
-weak_alias(__re_compile_pattern, re_compile_pattern)
-#endif
-/* Entry points compatible with 4.2 BSD regex library.  We don't define
-   them unless specifically requested.  */
-#if defined _REGEX_RE_COMP || defined _LIBC
-/* BSD has one and only one pattern buffer.  */
-static struct re_pattern_buffer re_comp_buf;
+					/* At least (most) this many matches must be made.  */
+					int lower_bound = -1, upper_bound = -1;
 
-char *
-#ifdef _LIBC
-/* Make these definitions weak in libc, so POSIX programs can redefine
-   these names if they don't use our functions, and still use
-   regcomp/regexec below without link errors.  */ weak_function
-#endif
-re_comp(s)
-const char *s;
-{
-	reg_errcode_t ret;
+					beg_interval = p - 1;
 
-	if (!s) {
-		if (!re_comp_buf.buffer)
-			return gettext("No previous regular expression");
-		return 0;
-	}
+					if (p == pend) {
+						if (!(syntax & RE_INTERVALS)
+							&& (syntax & RE_NO_BK_BRACES)) goto
+								unfetch_interval;
+						else
+							FREE_STACK_RETURN(REG_EBRACE);
+					}
 
-	if (!re_comp_buf.buffer) {
-		re_comp_buf.buffer = (unsigned char *) malloc(200);
-		if (re_comp_buf.buffer == NULL)
-			return (char *) gettext(re_error_msgid
-									+
-									re_error_msgid_idx[(int) REG_ESPACE]);
-		re_comp_buf.allocated = 200;
+					GET_UNSIGNED_NUMBER(lower_bound);
 
-		re_comp_buf.fastmap = (char *) malloc(1 << BYTEWIDTH);
-		if (re_comp_buf.fastmap == NULL)
-			return (char *) gettext(re_error_msgid
-									+
-									re_error_msgid_idx[(int) REG_ESPACE]);
-	}
+					if (c == ',') {
+						GET_UNSIGNED_NUMBER(upper_bound);
+						if ((!(syntax & RE_NO_BK_BRACES) && c != '\\')
+							|| ((syntax & RE_NO_BK_BRACES) && c != '}'))
+							FREE_STACK_RETURN(REG_BADBR);
 
-	/* Since `re_exec' always passes NULL for the `regs' argument, we
-	   don't need to initialize the pattern buffer fields which affect it.  */
+						if (upper_bound < 0)
+							upper_bound = RE_DUP_MAX;
+					} else
+						/* Interval such as `{1}' => match exactly once. */
+						upper_bound = lower_bound;
 
-	/* Match anchors at newlines.  */
-	re_comp_buf.newline_anchor = 1;
+					if (lower_bound < 0 || upper_bound > RE_DUP_MAX
+						|| lower_bound > upper_bound) {
+						if (!(syntax & RE_INTERVALS)
+							&& (syntax & RE_NO_BK_BRACES)) goto
+								unfetch_interval;
+						else
+							FREE_STACK_RETURN(REG_BADBR);
+					}
 
-	ret = regex_compile(s, strlen(s), re_syntax_options, &re_comp_buf);
+					if (!(syntax & RE_NO_BK_BRACES)) {
+						if (c != '\\')
+							FREE_STACK_RETURN(REG_EBRACE);
 
-	if (!ret)
-		return NULL;
+						PATFETCH(c);
+					}
 
-	/* Yes, we're discarding `const' here if !HAVE_LIBINTL.  */
-	return (char *) gettext(re_error_msgid +
-							re_error_msgid_idx[(int) ret]);
-}
+					if (c != '}') {
+						if (!(syntax & RE_INTERVALS)
+							&& (syntax & RE_NO_BK_BRACES)) goto
+								unfetch_interval;
+						else
+							FREE_STACK_RETURN(REG_BADBR);
+					}
 
+					/* We just parsed a valid interval.  */
 
-int
-#ifdef _LIBC
- weak_function
-#endif
-re_exec(s)
-const char *s;
-{
-	const int len = strlen(s);
+					/* If it's invalid to have no preceding re.  */
+					if (!laststart) {
+						if (syntax & RE_CONTEXT_INVALID_OPS)
+							FREE_STACK_RETURN(REG_BADRPT);
+						else if (syntax & RE_CONTEXT_INDEP_OPS)
+							laststart = b;
+						else
+							goto unfetch_interval;
+					}
 
-	return
-		0 <= re_search(&re_comp_buf, s, len, 0, len,
-					   (struct re_registers *) 0);
-}
+					/* If the upper bound is zero, don't want to succeed at
+					   all; jump from `laststart' to `b + 3', which will be
+					   the end of the buffer after we insert the jump.  */
+					if (upper_bound == 0) {
+						GET_BUFFER_SPACE(3);
+						INSERT_JUMP(jump, laststart, b + 3);
+						b += 3;
+					}
 
-#endif							/* _REGEX_RE_COMP */
-
-/* POSIX.2 functions.  Don't define these for Emacs.  */
+					/* Otherwise, we have a nontrivial interval.  When
+					   we're all done, the pattern will look like:
+					   set_number_at <jump count> <upper bound>
+					   set_number_at <succeed_n count> <lower bound>
+					   succeed_n <after jump addr> <succeed_n count>
+					   <body of loop>
+					   jump_n <succeed_n addr> <jump count>
+					   (The upper bound and `jump_n' are omitted if
+					   `upper_bound' is 1, though.)  */
+					else {		/* If the upper bound is > 1, we need to insert
+								   more at the end of the loop.  */
+						unsigned nbytes = 10 + (upper_bound > 1) * 10;
 
-#ifndef emacs
+						GET_BUFFER_SPACE(nbytes);
 
-/* regcomp takes a regular expression as a string and compiles it.
+						/* Initialize lower bound of the `succeed_n', even
+						   though it will be set during matching by its
+						   attendant `set_number_at' (inserted next),
+						   because `re_compile_fastmap' needs to know.
+						   Jump to the `jump_n' we might insert below.  */
+						INSERT_JUMP2(succeed_n, laststart,
+									 b + 5 + (upper_bound > 1) * 5,
+									 lower_bound);
+						b += 5;
 
-   PREG is a regex_t *.  We do not expect any fields to be initialized,
-   since POSIX says we shouldn't.  Thus, we set
+						/* Code to initialize the lower bound.  Insert
+						   before the `succeed_n'.  The `5' is the last two
+						   bytes of this `set_number_at', plus 3 bytes of
+						   the following `succeed_n'.  */
+						insert_op2(set_number_at, laststart, 5,
+								   lower_bound, b);
+						b += 5;
 
-     `buffer' to the compiled pattern;
-     `used' to the length of the compiled pattern;
-     `syntax' to RE_SYNTAX_POSIX_EXTENDED if the
-       REG_EXTENDED bit in CFLAGS is set; otherwise, to
-       RE_SYNTAX_POSIX_BASIC;
-     `newline_anchor' to REG_NEWLINE being set in CFLAGS;
-     `fastmap' to an allocated space for the fastmap;
-     `fastmap_accurate' to zero;
-     `re_nsub' to the number of subexpressions in PATTERN.
+						if (upper_bound > 1) {	/* More than one repetition is allowed, so
+												   append a backward jump to the `succeed_n'
+												   that starts this interval.
 
-   PATTERN is the address of the pattern string.
+												   When we've reached this during matching,
+												   we'll have matched the interval once, so
+												   jump back only `upper_bound - 1' times.  */
+							STORE_JUMP2(jump_n, b, laststart + 5,
+										upper_bound - 1);
+							b += 5;
 
-   CFLAGS is a series of bits which affect compilation.
+							/* The location we want to set is the second
+							   parameter of the `jump_n'; that is `b-2' as
+							   an absolute address.  `laststart' will be
+							   the `set_number_at' we're about to insert;
+							   `laststart+3' the number to set, the source
+							   for the relative address.  But we are
+							   inserting into the middle of the pattern --
+							   so everything is getting moved up by 5.
+							   Conclusion: (b - 2) - (laststart + 3) + 5,
+							   i.e., b - laststart.
 
-     If REG_EXTENDED is set, we use POSIX extended syntax; otherwise, we
-     use POSIX basic syntax.
+							   We insert this at the beginning of the loop
+							   so that if we fail during matching, we'll
+							   reinitialize the bounds.  */
+							insert_op2(set_number_at, laststart,
+									   b - laststart, upper_bound - 1, b);
+							b += 5;
+						}
+					}
+					pending_exact = 0;
+					beg_interval = NULL;
+				}
+				break;
 
-     If REG_NEWLINE is set, then . and [^...] don't match newline.
-     Also, regexec will try a match beginning after every newline.
+			  unfetch_interval:
+				/* If an invalid interval, match the characters as literals.  */
+				assert(beg_interval);
+				p = beg_interval;
+				beg_interval = NULL;
 
-     If REG_ICASE is set, then we considers upper- and lowercase
-     versions of letters to be equivalent when matching.
+				/* normal_char and normal_backslash need `c'.  */
+				PATFETCH(c);
 
-     If REG_NOSUB is set, then when PREG is passed to regexec, that
-     routine will report only success or failure, and nothing about the
-     registers.
+				if (!(syntax & RE_NO_BK_BRACES)) {
+					if (p > pattern && p[-1] == '\\')
+						goto normal_backslash;
+				}
+				goto normal_char;
 
-   It returns 0 if it succeeds, nonzero if it doesn't.  (See regex.h for
-   the return codes and their meanings.)  */
+#ifdef emacs
+				/* There is no way to specify the before_dot and after_dot
+				   operators.  rms says this is ok.  --karl  */
+			case '=':
+				BUF_PUSH(at_dot);
+				break;
 
-int regcomp(preg, pattern, cflags)
-regex_t *preg;
-const char *pattern;
-int cflags;
-{
-	reg_errcode_t ret;
-	reg_syntax_t syntax
-		= (cflags & REG_EXTENDED) ?
+			case 's':
+				laststart = b;
+				PATFETCH(c);
+				BUF_PUSH_2(syntaxspec, syntax_spec_code[c]);
+				break;
 
-		RE_SYNTAX_POSIX_EXTENDED : RE_SYNTAX_POSIX_BASIC;
+			case 'S':
+				laststart = b;
+				PATFETCH(c);
+				BUF_PUSH_2(notsyntaxspec, syntax_spec_code[c]);
+				break;
+#endif							/* emacs */
 
-	/* regex_compile will allocate the space for the compiled pattern.  */
-	preg->buffer = 0;
-	preg->allocated = 0;
-	preg->used = 0;
 
-	/* Try to allocate space for the fastmap.  */
-	preg->fastmap = (char *) malloc(1 << BYTEWIDTH);
+			case 'w':
+				if (syntax & RE_NO_GNU_OPS)
+					goto normal_char;
+				laststart = b;
+				BUF_PUSH(wordchar);
+				break;
 
-	if (cflags & REG_ICASE) {
-		unsigned i;
 
-		preg->translate
-			= (RE_TRANSLATE_TYPE) malloc(CHAR_SET_SIZE
-										 * sizeof(*(RE_TRANSLATE_TYPE) 0));
-		if (preg->translate == NULL)
-			return (int) REG_ESPACE;
+			case 'W':
+				if (syntax & RE_NO_GNU_OPS)
+					goto normal_char;
+				laststart = b;
+				BUF_PUSH(notwordchar);
+				break;
 
-		/* Map uppercase characters to corresponding lowercase ones.  */
-		for (i = 0; i < CHAR_SET_SIZE; i++)
-			preg->translate[i] = ISUPPER(i) ? TOLOWER(i) : i;
-	} else
-		preg->translate = NULL;
 
-	/* If REG_NEWLINE is set, newlines are treated differently.  */
-	if (cflags & REG_NEWLINE) {	/* REG_NEWLINE implies neither . nor [^...] match newline.  */
-		syntax &= ~RE_DOT_NEWLINE;
-		syntax |= RE_HAT_LISTS_NOT_NEWLINE;
-		/* It also changes the matching behavior.  */
-		preg->newline_anchor = 1;
-	} else
-		preg->newline_anchor = 0;
+			case '<':
+				if (syntax & RE_NO_GNU_OPS)
+					goto normal_char;
+				BUF_PUSH(wordbeg);
+				break;
 
-	preg->no_sub = !!(cflags & REG_NOSUB);
+			case '>':
+				if (syntax & RE_NO_GNU_OPS)
+					goto normal_char;
+				BUF_PUSH(wordend);
+				break;
 
-	/* POSIX says a null character in the pattern terminates it, so we
-	   can use strlen here in compiling the pattern.  */
-	ret = regex_compile(pattern, strlen(pattern), syntax, preg);
+			case 'b':
+				if (syntax & RE_NO_GNU_OPS)
+					goto normal_char;
+				BUF_PUSH(wordbound);
+				break;
 
-	/* POSIX doesn't distinguish between an unmatched open-group and an
-	   unmatched close-group: both are REG_EPAREN.  */
-	if (ret == REG_ERPAREN)
-		ret = REG_EPAREN;
+			case 'B':
+				if (syntax & RE_NO_GNU_OPS)
+					goto normal_char;
+				BUF_PUSH(notwordbound);
+				break;
 
-	if (ret == REG_NOERROR && preg->fastmap) {
-		/* Compute the fastmap now, since regexec cannot modify the pattern
-		   buffer.  */
-		if (re_compile_fastmap(preg) == -2) {
-			/* Some error occurred while computing the fastmap, just forget
-			   about it.  */
-			free(preg->fastmap);
-			preg->fastmap = NULL;
-		}
-	}
+			case '`':
+				if (syntax & RE_NO_GNU_OPS)
+					goto normal_char;
+				BUF_PUSH(begbuf);
+				break;
 
-	return (int) ret;
-}
+			case '\'':
+				if (syntax & RE_NO_GNU_OPS)
+					goto normal_char;
+				BUF_PUSH(endbuf);
+				break;
 
-#ifdef _LIBC
-weak_alias(__regcomp, regcomp)
-#endif
-/* regexec searches for a given pattern, specified by PREG, in the
-   string STRING.
+			case '1':
+			case '2':
+			case '3':
+			case '4':
+			case '5':
+			case '6':
+			case '7':
+			case '8':
+			case '9':
+				if (syntax & RE_NO_BK_REFS)
+					goto normal_char;
 
-   If NMATCH is zero or REG_NOSUB was set in the cflags argument to
-   `regcomp', we ignore PMATCH.  Otherwise, we assume PMATCH has at
-   least NMATCH elements, and we set them to the offsets of the
-   corresponding matched substrings.
+				c1 = c - '0';
 
-   EFLAGS specifies `execution flags' which affect matching: if
-   REG_NOTBOL is set, then ^ does not match at the beginning of the
-   string; if REG_NOTEOL is set, then $ does not match at the end.
+				if (c1 > regnum)
+					FREE_STACK_RETURN(REG_ESUBREG);
 
-   We return 0 if we find a match and REG_NOMATCH if not.  */
-int regexec(preg, string, nmatch, pmatch, eflags)
-const regex_t *preg;
-const char *string;
-size_t nmatch;
-regmatch_t pmatch[];
-int eflags;
-{
-	int ret;
-	struct re_registers regs;
-	regex_t private_preg;
-	int len = strlen(string);
-	boolean want_reg_info = !preg->no_sub && nmatch > 0;
+				/* Can't back reference to a subexpression if inside of it.  */
+				if (group_in_compile_stack(compile_stack, (regnum_t) c1))
+					goto normal_char;
 
-	private_preg = *preg;
+				laststart = b;
+				BUF_PUSH_2(duplicate, c1);
+				break;
 
-	private_preg.not_bol = !!(eflags & REG_NOTBOL);
-	private_preg.not_eol = !!(eflags & REG_NOTEOL);
 
-	/* The user has told us exactly how many registers to return
-	   information about, via `nmatch'.  We have to pass that on to the
-	   matching routines.  */
-	private_preg.regs_allocated = REGS_FIXED;
+			case '+':
+			case '?':
+				if (syntax & RE_BK_PLUS_QM)
+					goto handle_plus;
+				else
+					goto normal_backslash;
 
-	if (want_reg_info) {
-		regs.num_regs = nmatch;
-		regs.start = TALLOC(nmatch * 2, regoff_t);
-		if (regs.start == NULL)
-			return (int) REG_NOMATCH;
-		regs.end = regs.start + nmatch;
-	}
+			default:
+			  normal_backslash:
+				/* You might think it would be useful for \ to mean
+				   not to translate; but if we don't translate it
+				   it will never match anything.  */
+				c = TRANSLATE(c);
+				goto normal_char;
+			}
+			break;
 
-	/* Perform the searching operation.  */
-	ret = re_search(&private_preg, string, len,
-					/* start: */ 0, /* range: */ len,
-					want_reg_info ? &regs : (struct re_registers *) 0);
 
-	/* Copy the register information to the POSIX structure.  */
-	if (want_reg_info) {
-		if (ret >= 0) {
-			unsigned r;
+		default:
+			/* Expects the character in `c'.  */
+		  normal_char:
+			/* If no exactn currently being built.  */
+			if (!pending_exact
+				/* If last exactn not at current position.  */
+				|| pending_exact + *pending_exact + 1 != b
+				/* We have only one byte following the exactn for the count.  */
+				|| *pending_exact == (1 << BYTEWIDTH) - 1
+				/* If followed by a repetition operator.  */
+				|| *p == '*' || *p == '^' || ((syntax & RE_BK_PLUS_QM)
+											  ? *p == '\\' && (p[1] == '+'
+															   || p[1] ==
+															   '?') : (*p
+																	   ==
+																	   '+'
+																	   ||
+																	   *p
+																	   ==
+																	   '?'))
+				|| ((syntax & RE_INTERVALS)
+					&& ((syntax & RE_NO_BK_BRACES)
+						? *p == '{' : (p[0] == '\\' && p[1] == '{')))) {
+				/* Start building a new exactn.  */
 
-			for (r = 0; r < nmatch; r++) {
-				pmatch[r].rm_so = regs.start[r];
-				pmatch[r].rm_eo = regs.end[r];
+				laststart = b;
+
+				BUF_PUSH_2(exactn, 0);
+				pending_exact = b - 1;
 			}
-		}
 
-		/* If we needed the temporary register info, free the space now.  */
-		free(regs.start);
-	}
+			BUF_PUSH(c);
+			(*pending_exact)++;
+			break;
+		}						/* switch (c) */
+	}							/* while p != pend */
 
-	/* We want zero return to mean success, unlike `re_search'.  */
-	return ret >= 0 ? (int) REG_NOERROR : (int) REG_NOMATCH;
-}
 
-#ifdef _LIBC
-weak_alias(__regexec, regexec)
-#endif
-/* Returns a message corresponding to an error code, ERRCODE, returned
-   from either regcomp or regexec.   We don't use PREG here.  */
-	size_t regerror(errcode, preg, errbuf, errbuf_size)
-int errcode;
-const regex_t *preg;
-char *errbuf;
-size_t errbuf_size;
-{
-	const char *msg;
-	size_t msg_size;
+	/* Through the pattern now.  */
 
-	if (errcode < 0 || errcode >= (int) (sizeof(re_error_msgid_idx)
-										 / sizeof(re_error_msgid_idx[0])))
-		/* Only error codes returned by the rest of the code should be passed
-		   to this routine.  If we are given anything else, or if other regex
-		   code generates an invalid error code, then the program has a bug.
-		   Dump core so we can fix it.  */
-		abort();
+	if (fixup_alt_jump)
+		STORE_JUMP(jump_past_alt, fixup_alt_jump, b);
 
-	msg = gettext(re_error_msgid + re_error_msgid_idx[errcode]);
+	if (!COMPILE_STACK_EMPTY)
+		FREE_STACK_RETURN(REG_EPAREN);
 
-	msg_size = strlen(msg) + 1;	/* Includes the null.  */
+	/* If we don't want backtracking, force success
+	   the first time we reach the end of the compiled pattern.  */
+	if (syntax & RE_NO_POSIX_BACKTRACKING)
+		BUF_PUSH(succeed);
 
-	if (errbuf_size != 0) {
-		if (msg_size > errbuf_size) {
-#if defined HAVE_MEMPCPY || defined _LIBC
-			*((char *) __mempcpy(errbuf, msg, errbuf_size - 1)) = '\0';
-#else
-			memcpy(errbuf, msg, errbuf_size - 1);
-			errbuf[errbuf_size - 1] = 0;
-#endif
-		} else
-			memcpy(errbuf, msg, msg_size);
-	}
+	free(compile_stack.stack);
 
-	return msg_size;
-}
+	/* We have succeeded; set the length of the buffer.  */
+	bufp->used = b - bufp->buffer;
 
-#ifdef _LIBC
-weak_alias(__regerror, regerror)
-#endif
-/* Free dynamically allocated space used by PREG.  */
-void regfree(preg)
-regex_t *preg;
-{
-	if (preg->buffer != NULL)
-		free(preg->buffer);
-	preg->buffer = NULL;
+#ifdef DEBUG
+	if (debug) {
+		DEBUG_PRINT1("\nCompiled pattern: \n");
+		print_compiled_pattern(bufp);
+	}
+#endif							/* DEBUG */
 
-	preg->allocated = 0;
-	preg->used = 0;
+#ifndef MATCH_MAY_ALLOCATE
+	/* Initialize the failure stack to the largest possible stack.  This
+	   isn't necessary unless we're trying to avoid calling alloca in
+	   the search and match routines.  */
+	{
+		int num_regs = bufp->re_nsub + 1;
 
-	if (preg->fastmap != NULL)
-		free(preg->fastmap);
-	preg->fastmap = NULL;
-	preg->fastmap_accurate = 0;
+		/* Since DOUBLE_FAIL_STACK refuses to double only if the current size
+		   is strictly greater than re_max_failures, the largest possible stack
+		   is 2 * re_max_failures failure points.  */
+		if (fail_stack.size < (2 * re_max_failures * MAX_FAILURE_ITEMS)) {
+			fail_stack.size = (2 * re_max_failures * MAX_FAILURE_ITEMS);
 
-	if (preg->translate != NULL)
-		free(preg->translate);
-	preg->translate = NULL;
-}
+# ifdef emacs
+			if (!fail_stack.stack)
+				fail_stack.stack
+					= (fail_stack_elt_t *) xmalloc(fail_stack.size
+												   *
+												   sizeof
+												   (fail_stack_elt_t));
+			else
+				fail_stack.stack =
+					(fail_stack_elt_t *) xrealloc(fail_stack.stack,
+												  (fail_stack.size *
+												   sizeof
+												   (fail_stack_elt_t)));
+# else							/* not emacs */
+			if (!fail_stack.stack)
+				fail_stack.stack
+					= (fail_stack_elt_t *) malloc(fail_stack.size
+												  *
+												  sizeof
+												  (fail_stack_elt_t));
+			else
+				fail_stack.stack =
+					(fail_stack_elt_t *) realloc(fail_stack.stack,
+												 (fail_stack.size *
+												  sizeof
+												  (fail_stack_elt_t)));
+# endif							/* not emacs */
+		}
 
-#ifdef _LIBC
-weak_alias(__regfree, regfree)
-#endif
-#endif							/* not emacs  */
+		regex_grow_registers(num_regs);
+	}
+#endif							/* not MATCH_MAY_ALLOCATE */
+
+	return REG_NOERROR;
+}								/* regex_compile */