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S390: Fix fp comparison not raising FE_INVALID.

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As gcc is using unordered comparison instructions which do not
raise invalid exception if any operand is quiet NAN,
FIX_COMPARE_INVALID is defined to 1.
Thus iseqsig is calling feraiseexcept as workaround.
This commit is contained in:
Stefan Liebler 2016-10-17 10:37:11 +02:00
parent 7cfde84069
commit 8e36adc08e
2 changed files with 40 additions and 0 deletions
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2016-10-17 Stefan Liebler <stli@linux.vnet.ibm.com>
* sysdeps/s390/fpu/fix-fp-int-compare-invalid.h: New file.
2016-09-22 John David Anglin <dave.anglin@bell.net>
* sysdeps/unix/sysv/linux/hppa/atomic-machine.h: Don't include

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sysdeps/s390/fpu/fix-fp-int-compare-invalid.h Normal file
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/* Fix for missing "invalid" exceptions from floating-point
comparisons. s390 version.
Copyright (C) 2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef FIX_FP_INT_COMPARE_INVALID_H
#define FIX_FP_INT_COMPARE_INVALID_H 1
/* GCC uses unordered comparison instructions like cebr (Short BFP COMPARE)
when it should use ordered comparison instructions like kebr
(Short BFP COMPARE AND SIGNAL) in order to raise invalid exceptions if
any operand is quiet (or signaling) NAN. See gcc bugzilla:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77918>.
There exists an equivalent gcc bugzilla for Intel:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52451>.
Once the s390 gcc bug is fixed, the definition of FIX_COMPARE_INVALID
should have a __GNUC_PREREQ conditional added so that e.g. the workaround
to call feraiseexcept (FE_INVALID) in math/s_iseqsig_template.c can be
avoided. */
#define FIX_COMPARE_INVALID 1
#endif /* fix-fp-int-compare-invalid.h */