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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.
103 lines
3.5 KiB
C
103 lines
3.5 KiB
C
/* Macros to control TS 18661-3 glibc features on ia64.
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Copyright (C) 2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _BITS_FLOATN_H
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#define _BITS_FLOATN_H
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#include <features.h>
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/* Defined to 1 if the current compiler invocation provides a
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floating-point type with the IEEE 754 binary128 format, and this
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glibc includes corresponding *f128 interfaces for it. The required
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libgcc support was added some time after the basic compiler
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support. */
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#if __GNUC_PREREQ (4, 4)
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# define __HAVE_FLOAT128 1
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#else
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# define __HAVE_FLOAT128 0
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#endif
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/* Defined to 1 if __HAVE_FLOAT128 is 1 and the type is ABI-distinct
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from the default float, double and long double types in this glibc. */
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#if __HAVE_FLOAT128
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# define __HAVE_DISTINCT_FLOAT128 1
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#else
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# define __HAVE_DISTINCT_FLOAT128 0
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#endif
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/* Defined to concatenate the literal suffix to be used with _Float128
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types, if __HAVE_FLOAT128 is 1. */
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#if __HAVE_FLOAT128
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# if !__GNUC_PREREQ (7, 0) || defined __cplusplus
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/* The literal suffix f128 exists only since GCC 7.0. */
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# define __f128(x) x##q
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# else
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# define __f128(x) x##f128
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# endif
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#endif
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/* Defined to a complex binary128 type if __HAVE_FLOAT128 is 1. */
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#if __HAVE_FLOAT128
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# if !__GNUC_PREREQ (7, 0) || defined __cplusplus
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/* Add a typedef for older GCC compilers which don't natively support
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_Complex _Float128. */
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typedef _Complex float __cfloat128 __attribute__ ((__mode__ (__TC__)));
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# define __CFLOAT128 __cfloat128
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# else
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# define __CFLOAT128 _Complex _Float128
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# endif
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#endif
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/* The remaining of this file provides support for older compilers. */
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#if __HAVE_FLOAT128
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/* The type _Float128 exists only since GCC 7.0. */
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# if !__GNUC_PREREQ (7, 0) || defined __cplusplus
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typedef __float128 _Float128;
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# endif
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/* __builtin_huge_valf128 doesn't exist before GCC 7.0. */
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# if !__GNUC_PREREQ (7, 0)
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# define __builtin_huge_valf128() ((_Float128) __builtin_huge_val ())
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# endif
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/* Older GCC has only a subset of built-in functions for _Float128 on
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ia64, and __builtin_infq is not usable in static initializers.
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Converting a narrower sNaN to _Float128 produces a quiet NaN, so
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attempts to use _Float128 sNaNs will not work properly with older
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compilers. */
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# if !__GNUC_PREREQ (7, 0)
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# define __builtin_copysignf128 __builtin_copysignq
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# define __builtin_fabsf128 __builtin_fabsq
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# define __builtin_inff128() ((_Float128) __builtin_inf ())
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# define __builtin_nanf128(x) ((_Float128) __builtin_nan (x))
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# define __builtin_nansf128(x) ((_Float128) __builtin_nans (x))
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# endif
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/* In math/math.h, __MATH_TG will expand signbit to __builtin_signbit*,
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e.g.: __builtin_signbitf128, before GCC 6. However, there has never
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been a __builtin_signbitf128 in GCC and the type-generic builtin is
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only available since GCC 6. */
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# if !__GNUC_PREREQ (6, 0)
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# define __builtin_signbitf128 __signbitf128
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# endif
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#endif
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#endif /* _BITS_FLOATN_H */
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