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- From f7439f9b1089e17b6721f28e228682831a2f0135 Mon Sep 17 00:00:00 2001
- From: "Gabriel F. T. Gomes" <gftg@linux.vnet.ibm.com>
- Date: Mon, 21 Aug 2017 14:23:27 +0200
- Subject: [PATCH] Do not use __builtin_types_compatible_p in C++ mode (bug
- 21930)
- The logic to define isinf for float128 depends on the availability of
- __builtin_types_compatible_p, which is only available in C mode,
- however, the conditionals do not check for C or C++ mode. This lead to
- an error in libstdc++ configure, as reported by bug 21930.
- This patch adds a conditional for C mode in the definition of isinf for
- float128. No definition is provided in C++ mode, since libstdc++
- headers undefine isinf.
- Tested for powerpc64le (glibc test suite and libstdc++-v3 configure).
- [BZ #21930]
- * math/math.h (isinf): Check if in C or C++ mode before using
- __builtin_types_compatible_p, since this is a C mode feature.
- (cherry picked from commit 47a67213a9f51c5f8816d240500b10db605d8b77)
- [Romain rebase on glibc 2.26]
- Signed-off-by: Romain Naour <romain.naour@gmail.com>
- ---
- math/math.h | 8 ++++++--
- 1 file changed, 6 insertions(+), 2 deletions(-)
- diff --git a/math/math.h b/math/math.h
- index e217080..dea8dbe 100644
- --- a/math/math.h
- +++ b/math/math.h
- @@ -442,8 +442,12 @@ enum
-
- /* Return nonzero value if X is positive or negative infinity. */
- # if __HAVE_DISTINCT_FLOAT128 && !__GNUC_PREREQ (7,0) \
- - && !defined __SUPPORT_SNAN__
- - /* __builtin_isinf_sign is broken for float128 only before GCC 7.0. */
- + && !defined __SUPPORT_SNAN__ && !defined __cplusplus
- + /* Since __builtin_isinf_sign is broken for float128 before GCC 7.0,
- + use the helper function, __isinff128, with older compilers. This is
- + only provided for C mode, because in C++ mode, GCC has no support
- + for __builtin_types_compatible_p (and when in C++ mode, this macro is
- + not used anyway, because libstdc++ headers undefine it). */
- # define isinf(x) \
- (__builtin_types_compatible_p (__typeof (x), _Float128) \
- ? __isinff128 (x) : __builtin_isinf_sign (x))
- --
- 2.9.5
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