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b0216d3e4d
The default (top-level) version of bits/mathdef.h defines float_t to double. It is used on ColdFire, MicroBlaze, Nios II and SH3, all of which define FLT_EVAL_METHOD to 0, so float_t should be float (and C11 requires a certain correspondence between these typedefs and FLT_EVAL_METHOD values). I proposed fixing this default in <https://sourceware.org/ml/libc-alpha/2015-01/msg00499.html>, with no objections from architecture maintainers, and this patch makes that fix. As noted in the NEWS entry added, this might affect the ABIs of non-glibc libraries (ImageMagick has been mentioned in gcc-patches discussion of the S/390 case - which is unaffected by this patch), but as noted in my previous message, affected libraries would have problems with -mfpmath=sse anyway on 32-bit x86. A (compilation) testcase is added to verify the required correspondence of typedefs to FLT_EVAL_METHOD values. This test is built with -fexcess-precision=standard to avoid any issues with GCC 7 on S/390 providing a more accurate FLT_EVAL_METHOD definition in the default (no excess precision) mode. (This will also be usable to test a fix for the recently reported bug about these typedefs on x86_64 -mfpmath=387, as architecture-specific tests can be added that It is entirely possible that the fixed default makes some architecture-specific versions of bits/mathdef.h semantically equivalent to the default version and so no longer required. I don't intend to investigate that separately from the refactoring I proposed in <https://sourceware.org/ml/libc-alpha/2016-11/msg00745.html>, which will create as few header variants as possible for each group of definitions. Tested (compilation only) with build-many-glibcs.py. [BZ #20855] * bits/mathdef.h (float_t): Define to float. * math/test-flt-eval-method.c: New file. * math/Makefile (tests): Add test-flt-eval-method. (CFLAGS-test-flt-eval-method.c): New variable.
57 lines
1.8 KiB
C
57 lines
1.8 KiB
C
/* Copyright (C) 1997-2016 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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#if !defined _MATH_H && !defined _COMPLEX_H
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# error "Never use <bits/mathdef.h> directly; include <math.h> instead"
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#endif
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#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
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# define _MATH_H_MATHDEF 1
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/* Expressions are evaluated with the range and precision of their
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type. */
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typedef float float_t; /* `float' expressions are evaluated as
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`float'. */
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typedef double double_t; /* `double' expressions are evaluated as
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`double'. */
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/* The values returned by `ilogb' for 0 and NaN respectively. */
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# define FP_ILOGB0 (-2147483647)
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# define FP_ILOGBNAN 2147483647
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/* The GCC 4.6 compiler will define __FP_FAST_FMA{,F,L} if the fma{,f,l}
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builtins are supported. */
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#ifdef __FP_FAST_FMA
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# define FP_FAST_FMA 1
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#endif
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#ifdef __FP_FAST_FMAF
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# define FP_FAST_FMAF 1
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#endif
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#ifdef __FP_FAST_FMAL
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# define FP_FAST_FMAL 1
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#endif
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#endif /* ISO C99 */
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#ifndef __NO_LONG_DOUBLE_MATH
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/* Signal that we do not really have a `long double'. The disables the
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declaration of all the `long double' function variants. */
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# define __NO_LONG_DOUBLE_MATH 1
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#endif
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