Fix i386/x86_64 fesetenv SSE exception clearing (bug 19181).

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.

	[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.

ChangeLog

@@ -1,5 +1,17 @@
 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.
+
 	* math/libm-test.inc (TYPE_DECIMAL_DIG): Use LDBL_DECIMAL_DIG,
 	DBL_DECIMAL_DIG and FLT_DECIMAL_DIG instead of __DECIMAL_DIG__,
 	__DBL_DECIMAL_DIG__ and __FLT_DECIMAL_DIG__.

NEWS

@@ -21,7 +21,7 @@ Version 2.23
   18969, 18970, 18977, 18980, 18981, 18982, 18985, 19003, 19007, 19012,
   19016, 19018, 19032, 19046, 19049, 19050, 19059, 19071, 19074, 19076,
   19077, 19078, 19079, 19085, 19086, 19088, 19094, 19095, 19124, 19125,
-  19129, 19134, 19137, 19156, 19174.
+  19129, 19134, 19137, 19156, 19174, 19181.
 
 * There is now a --disable-timezone-tools configure option for disabling the
   building and installing of the timezone related utilities (zic, zdump, and

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'.

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"

math/test-fenv-clear.c

@@ -0,0 +1,2 @@
+#define CHECK_CAN_TEST ((void) 0)
+#include <test-fenv-clear-main.c>

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.  */

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

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>

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;