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TS 18661-1 adds an iseqsig type-generic comparison macro to <math.h>. This macro is like the == operator except that unordered operands result in the "invalid" exception and errno being set to EDOM. This patch implements this macro for glibc. Given the need to set errno, this is implemented with out-of-line functions __iseqsigf, __iseqsig and __iseqsigl (of which the last only exists at all if long double is ABI-distinct from double, so no function aliases or compat support are needed). The present patch ignores excess precision issues; I intend to deal with those in a followup patch. (Like comparison operators, type-generic comparison macros should *not* convert operands to their semantic types but should preserve excess range and precision, meaning that for some argument types and values of FLT_EVAL_METHOD, an underlying function should be called for a wider type than that of the arguments.) The underlying functions are implemented with the type-generic template machinery. Comparing x <= y && x >= y is sufficient in ISO C to achieve an equality comparison with "invalid" raised for unordered operands (and the results of those two comparisons can also be used to tell whether errno needs to be set). However, some architectures have GCC bugs meaning that unordered comparison instructions are used instead of ordered ones. Thus, a mechanism is provided for architectures to use an explicit call to feraiseexcept to raise exceptions if required. If your architecture has such a bug you should add a fix-fp-int-compare-invalid.h header for it, with a comment pointing to the relevant GCC bug report; if such a GCC bug is fixed, that header's contents should have a __GNUC_PREREQ conditional added so that the workaround can eventually be removed for that architecture. Tested for x86_64, x86, mips64, arm and powerpc. * math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (iseqsig): New macro. * math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (__iseqsig): New declaration. * math/s_iseqsig_template.c: New file. * math/Versions (__iseqsigf): New libm symbol at version GLIBC_2.25. (__iseqsig): Likewise. (__iseqsigl): Likewise. * math/libm-test.inc (iseqsig_test_data): New array. (iseqsig_test): New function. (main): Call iseqsig_test. * math/Makefile (gen-libm-calls): Add s_iseqsigF. * manual/arith.texi (FP Comparison Functions): Document iseqsig. * manual/libm-err-tab.pl: Update comment on interfaces without ulps tabulated. * sysdeps/generic/fix-fp-int-compare-invalid.h: New file. * sysdeps/powerpc/fpu/fix-fp-int-compare-invalid.h: Likewise. * sysdeps/x86/fpu/fix-fp-int-compare-invalid.h: Likewise. * sysdeps/nacl/libm.abilist: Update. * sysdeps/unix/sysv/linux/aarch64/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/alpha/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/arm/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/hppa/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/microblaze/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/nios2/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/sh/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.
28 lines
1.1 KiB
C
28 lines
1.1 KiB
C
/* Fix for missing "invalid" exceptions from floating-point
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comparisons. Generic version.
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Copyright (C) 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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#ifndef FIX_FP_INT_COMPARE_INVALID_H
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#define FIX_FP_INT_COMPARE_INVALID_H 1
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/* Define this macro to 1 to work around ordered comparison operators
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in C failing to raise the "invalid" exception for NaN operands. */
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#define FIX_COMPARE_INVALID 0
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#endif /* fix-fp-int-compare-invalid.h */
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