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Make x86_64 fegetenv preserve exception mask (bug 16198).

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Bug 16198 is x86_64 fegetenv wrongly masking exceptions for which
traps are enabled, because that's a side-effect of the fnstenv
instruction.  This patch fixes it to use fldenv immediately after
fnstenv, like the i386 version.  Tested x86_64 and x86.

	[BZ #16198]
	* sysdeps/x86_64/fpu/fegetenv.c (fegetenv): Use fldenv after
	fnstenv.
	* math/test-fenv-preserve.c: New file.
	* math/Makefile (tests): Add test-fenv-preserve.
This commit is contained in:
Joseph Myers 2014-03-26 18:59:08 +00:00
parent 60a2f3c166
commit 9be36fb8cb
5 changed files with 69 additions and 5 deletions
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8
ChangeLog
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@ -1,3 +1,11 @@
2014-03-26 Joseph Myers <joseph@codesourcery.com>
[BZ #16198]
* sysdeps/x86_64/fpu/fegetenv.c (fegetenv): Use fldenv after
fnstenv.
* math/test-fenv-preserve.c: New file.
* math/Makefile (tests): Add test-fenv-preserve.
2014-03-26 Will Newton <will.newton@linaro.org>
* benchtests/bench-strtod.c (TIMEOUT): Define to 10.

8
NEWS
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@ -9,10 +9,10 @@ Version 2.20
* The following bugs are resolved with this release:
15347, 15804, 15894, 16002, 16284, 16357, 16447, 16532, 16545, 16574,
16599, 16600, 16609, 16610, 16611, 16613, 16623, 16632, 16634, 16639,
16642, 16649, 16670, 16674, 16677, 16680, 16683, 16689, 16695, 16701,
16706, 16707, 16712, 16713, 16714, 16731, 16743.
15347, 15804, 15894, 16002, 16198, 16284, 16357, 16447, 16532, 16545,
16574, 16599, 16600, 16609, 16610, 16611, 16613, 16623, 16632, 16634,
16639, 16642, 16649, 16670, 16674, 16677, 16680, 16683, 16689, 16695,
16701, 16706, 16707, 16712, 16713, 16714, 16731, 16743.
* Running the testsuite no longer terminates as soon as a test fails.
Instead, a file tests.sum (xtests.sum from "make xcheck") is generated,

2
math/Makefile
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@ -90,7 +90,7 @@ tests = test-matherr test-fenv atest-exp atest-sincos atest-exp2 basic-test \
test-misc test-fpucw test-fpucw-ieee tst-definitions test-tgmath \
test-tgmath-ret bug-nextafter bug-nexttoward bug-tgmath1 \
test-tgmath-int test-tgmath2 test-powl tst-CMPLX tst-CMPLX2 test-snan \
test-fenv-tls $(tests-static)
test-fenv-tls test-fenv-preserve $(tests-static)
tests-static = test-fpucw-static test-fpucw-ieee-static
# We do the `long double' tests only if this data type is available and
# distinct from `double'.

53
math/test-fenv-preserve.c Normal file
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@ -0,0 +1,53 @@
/* Test fegetenv preserves exception mask (bug 16198).
Copyright (C) 2014 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/>. */
#include <fenv.h>
#include <stdio.h>
static int
do_test (void)
{
fenv_t env;
if (feenableexcept (FE_INVALID) != 0)
{
puts ("feenableexcept (FE_INVALID) failed, cannot test");
return 0;
}
if (fegetenv (&env) != 0)
{
puts ("fegetenv failed, cannot test");
return 0;
}
int ret = fegetexcept ();
if (ret == FE_INVALID)
{
puts ("fegetenv preserved exception mask, OK");
return 0;
}
else
{
printf ("fegetexcept returned %d, expected %d\n", ret, FE_INVALID);
return 1;
}
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"

3
sysdeps/x86_64/fpu/fegetenv.c
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@ -22,6 +22,9 @@ int
fegetenv (fenv_t *envp)
{
__asm__ ("fnstenv %0\n"
/* fnstenv changes the exception mask, so load back the
stored environment. */
"fldenv %0\n"
"stmxcsr %1" : "=m" (*envp), "=m" (envp->__mxcsr));
/* Success. */