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| author | Gabriel F. T. Gomes <gftg@linux.vnet.ibm.com> | 2017-06-29 15:34:05 -0300 |
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| committer | Gabriel F. T. Gomes <gftg@linux.vnet.ibm.com> | 2017-06-30 18:34:29 -0300 |
| commit | 8466ee1cb7c2041d8471dad0aa53af35ab599012 (patch) | |
| tree | b448538ed77b0a029712d8ba134b18675d5c1413 /sysdeps/x86/bits | |
| parent | 9b8f8593e5d919d8ea9a5f21ce7473246651ec2f (diff) | |
| download | glibc-8466ee1cb7c2041d8471dad0aa53af35ab599012.tar.gz glibc-8466ee1cb7c2041d8471dad0aa53af35ab599012.tar.xz glibc-8466ee1cb7c2041d8471dad0aa53af35ab599012.zip | |
float128: Add signbit alternative for old compilers
In math/math.h, __MATH_TG will expand signbit to __builtin_signbit*, e.g.: __builtin_signbitf128, before GCC 6. However, there has never been a __builtin_signbitf128 in GCC and the type-generic builtin is only available since GCC 6. For older GCC, this patch defines __builtin_signbitf128 to __signbitf128, so that the internal function is used instead of the non-existent builtin. This patch also changes the implementation of __signbitf128, because it was reusing the implementation of __signbitl from ldbl-128, which calls __builtin_signbitl. Using the long double version of the builtin is not correct on machines where _Float128 is ABI-distinct from long double (i.e.: ia64, powerpc64le, x86, x86_84). The new implementation does not rely on builtins when being built with GCC versions older than 6.0. The new code does not currently affect powerpc64le builds, because only GCC 6.2 fulfills the requirements from configure. It might affect powerpc64le builds if those requirements are backported to older versions of the compiler. The new code affects x86_64 builds, since glibc is supposed to build correctly with older versions of GCC. Tested for powerpc64le and x86_64. * include/math.h (__signbitf128): Define as hidden. * sysdeps/ieee754/float128/s_signbitf128.c (__signbitf128): Reimplement without builtins. * sysdeps/ia64/bits/floatn.h [!__GNUC_PREREQ (6, 0)] (__builtin_signbitf128): Define to __signbitf128. * sysdeps/powerpc/bits/floatn.h: Likewise. * sysdeps/x86/bits/floatn.h: Likewise.
Diffstat (limited to 'sysdeps/x86/bits')
| -rw-r--r-- | sysdeps/x86/bits/floatn.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/sysdeps/x86/bits/floatn.h b/sysdeps/x86/bits/floatn.h index 23f74782ea..f93a9f8dbb 100644 --- a/sysdeps/x86/bits/floatn.h +++ b/sysdeps/x86/bits/floatn.h @@ -91,6 +91,14 @@ typedef __float128 _Float128; # define __builtin_nansf128(x) ((_Float128) __builtin_nans (x)) # endif +/* In math/math.h, __MATH_TG will expand signbit to __builtin_signbit*, + e.g.: __builtin_signbitf128, before GCC 6. However, there has never + been a __builtin_signbitf128 in GCC and the type-generic builtin is + only available since GCC 6. */ +# if !__GNUC_PREREQ (6, 0) +# define __builtin_signbitf128 __signbitf128 +# endif + #endif #endif /* _BITS_FLOATN_H */ |