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Fix i386/x86_64 fesetenv SSE exception clearing (bug 19181)
- From: Joseph Myers <joseph at codesourcery dot com>
- To: <libc-alpha at sourceware dot org>
- Date: Wed, 28 Oct 2015 18:50:59 +0000
- Subject: Fix i386/x86_64 fesetenv SSE exception clearing (bug 19181)
- Authentication-results: sourceware.org; auth=none
The i386 and x86_64 versions of fesetenv, when called with FE_DFL_ENV
or FE_NOMASK_ENV as argument, do not clear SSE exceptions raised in
MXCSR. These arguments should, like other fenv_t values, represent
the whole of the floating-point state, so such exceptions should be
cleared; this patch adds the required clearing. (Discovered while
working on bug 16068.)
Tested for x86_64 and x86.
2015-10-28 Joseph Myers <joseph@codesourcery.com>
[BZ #19181]
* sysdeps/i386/fpu/fesetenv.c (__fesetenv): Clear already-raised
SSE exceptions when argument is FE_DFL_ENV or FE_NOMASK_ENV.
* sysdeps/x86_64/fpu/fesetenv.c (__fesetenv): Likewise.
* math/test-fenv-clear-main.c: New file.
* math/test-fenv-clear.c: Likewise.
* math/Makefile (tests): Add test-fenv-clear.
* sysdeps/x86/fpu/test-fenv-clear-sse.c: New file.
* sysdeps/x86/fpu/Makefile [$(subdir) = math] (tests): Add
test-fenv-clear-sse.
[$(subdir) = math] (CFLAGS-test-fenv-clear-sse.c): New variable.
diff --git a/math/Makefile b/math/Makefile
index 97004f9..dedd7ee 100644
--- a/math/Makefile
+++ b/math/Makefile
@@ -108,7 +108,7 @@ tests = test-matherr test-fenv atest-exp atest-sincos atest-exp2 basic-test \
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 test-fenv-preserve test-fenv-return test-fenvinline \
- test-nearbyint-except $(tests-static)
+ test-nearbyint-except test-fenv-clear $(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'.
diff --git a/math/test-fenv-clear-main.c b/math/test-fenv-clear-main.c
new file mode 100644
index 0000000..5611192
--- /dev/null
+++ b/math/test-fenv-clear-main.c
@@ -0,0 +1,91 @@
+/* Test fesetenv (FE_DFL_ENV) and fesetenv (FE_NOMASK_ENV) clear
+ exceptions (bug 19181).
+ Copyright (C) 2015 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 <float.h>
+#include <stdio.h>
+
+volatile float fa = 1.0f, fb = 0.0f, fc = FLT_MAX, fr;
+volatile long double lda = 1.0L, ldb = 0.0L, ldc = LDBL_MAX, ldr;
+
+static void
+raise_exceptions (void)
+{
+ /* Raise exceptions both with feraiseexcept and arithmetic to allow
+ for case of multiple floating-point units with separate
+ exceptions state. */
+ feraiseexcept (FE_ALL_EXCEPT);
+ fr = fb / fb;
+ fr = fa / fb;
+ fr = fc * fc;
+ fr = fa / fc / fc;
+ ldr = ldb / ldb;
+ ldr = lda / ldb;
+ ldr = ldc * ldc;
+ ldr = lda / ldc / ldc;
+}
+
+static __attribute__ ((noinline)) int
+run_tests (void)
+{
+ int result = 0;
+ raise_exceptions ();
+ if (fesetenv (FE_DFL_ENV) == 0)
+ {
+ puts ("PASS: fesetenv (FE_DFL_ENV)");
+ if (fetestexcept (FE_ALL_EXCEPT) == 0)
+ puts ("PASS: fesetenv (FE_DFL_ENV) clearing exceptions");
+ else
+ {
+ puts ("FAIL: fesetenv (FE_DFL_ENV) clearing exceptions");
+ result = 1;
+ }
+ }
+ else
+ {
+ puts ("FAIL: fesetenv (FE_DFL_ENV)");
+ result = 1;
+ }
+#ifdef FE_NOMASK_ENV
+ raise_exceptions ();
+ if (fesetenv (FE_NOMASK_ENV) == 0)
+ {
+ if (fetestexcept (FE_ALL_EXCEPT) == 0)
+ puts ("PASS: fesetenv (FE_NOMASK_ENV) clearing exceptions");
+ else
+ {
+ puts ("FAIL: fesetenv (FE_NOMASK_ENV) clearing exceptions");
+ result = 1;
+ }
+ }
+ else
+ puts ("fesetenv (FE_NOMASK_ENV) failed, cannot test");
+#endif
+ return result;
+}
+
+static int
+do_test (void)
+{
+ CHECK_CAN_TEST;
+ return run_tests ();
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
diff --git a/math/test-fenv-clear.c b/math/test-fenv-clear.c
new file mode 100644
index 0000000..5559dd3
--- /dev/null
+++ b/math/test-fenv-clear.c
@@ -0,0 +1,2 @@
+#define CHECK_CAN_TEST ((void) 0)
+#include <test-fenv-clear-main.c>
diff --git a/sysdeps/i386/fpu/fesetenv.c b/sysdeps/i386/fpu/fesetenv.c
index 9566e09..910aa09 100644
--- a/sysdeps/i386/fpu/fesetenv.c
+++ b/sysdeps/i386/fpu/fesetenv.c
@@ -72,6 +72,8 @@ __fesetenv (const fenv_t *envp)
if (envp == FE_DFL_ENV)
{
+ /* Clear SSE exceptions. */
+ mxcsr &= ~FE_ALL_EXCEPT;
/* Set mask for SSE MXCSR. */
mxcsr |= (FE_ALL_EXCEPT << 7);
/* Set rounding to FE_TONEAREST. */
@@ -80,6 +82,8 @@ __fesetenv (const fenv_t *envp)
}
else if (envp == FE_NOMASK_ENV)
{
+ /* Clear SSE exceptions. */
+ mxcsr &= ~FE_ALL_EXCEPT;
/* Do not mask exceptions. */
mxcsr &= ~(FE_ALL_EXCEPT << 7);
/* Set rounding to FE_TONEAREST. */
diff --git a/sysdeps/x86/fpu/Makefile b/sysdeps/x86/fpu/Makefile
index 9cb7bb2..d38497c 100644
--- a/sysdeps/x86/fpu/Makefile
+++ b/sysdeps/x86/fpu/Makefile
@@ -1,5 +1,6 @@
ifeq ($(subdir),math)
libm-support += powl_helper
-tests += test-fenv-sse
+tests += test-fenv-sse test-fenv-clear-sse
CFLAGS-test-fenv-sse.c += -msse2 -mfpmath=sse
+CFLAGS-test-fenv-clear-sse.c += -msse2 -mfpmath=sse
endif
diff --git a/sysdeps/x86/fpu/test-fenv-clear-sse.c b/sysdeps/x86/fpu/test-fenv-clear-sse.c
new file mode 100644
index 0000000..531164c
--- /dev/null
+++ b/sysdeps/x86/fpu/test-fenv-clear-sse.c
@@ -0,0 +1,45 @@
+/* Test fesetenv (FE_DFL_ENV) and fesetenv (FE_NOMASK_ENV) clear
+ exceptions (bug 19181). SSE version.
+ Copyright (C) 2015 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 <cpuid.h>
+#include <stdbool.h>
+
+static bool
+have_sse2 (void)
+{
+ unsigned int eax, ebx, ecx, edx;
+
+ if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+ return false;
+
+ return (edx & bit_SSE2) != 0;
+}
+
+#define CHECK_CAN_TEST \
+ do \
+ { \
+ if (!have_sse2 ()) \
+ { \
+ puts ("CPU does not support SSE2, cannot test"); \
+ return 0; \
+ } \
+ } \
+ while (0)
+
+#include <test-fenv-clear-main.c>
diff --git a/sysdeps/x86_64/fpu/fesetenv.c b/sysdeps/x86_64/fpu/fesetenv.c
index 3e3fd84..9950aa7 100644
--- a/sysdeps/x86_64/fpu/fesetenv.c
+++ b/sysdeps/x86_64/fpu/fesetenv.c
@@ -42,6 +42,8 @@ __fesetenv (const fenv_t *envp)
temp.__opcode = 0;
temp.__data_offset = 0;
temp.__data_selector = 0;
+ /* Clear SSE exceptions. */
+ temp.__mxcsr &= ~FE_ALL_EXCEPT;
/* Set mask for SSE MXCSR. */
temp.__mxcsr |= (FE_ALL_EXCEPT << 7);
/* Set rounding to FE_TONEAREST. */
@@ -57,6 +59,8 @@ __fesetenv (const fenv_t *envp)
temp.__opcode = 0;
temp.__data_offset = 0;
temp.__data_selector = 0;
+ /* Clear SSE exceptions. */
+ temp.__mxcsr &= ~FE_ALL_EXCEPT;
/* Set mask for SSE MXCSR. */
/* Set rounding to FE_TONEAREST. */
temp.__mxcsr &= ~ 0x6000;
--
Joseph S. Myers
joseph@codesourcery.com