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.

3 files changed, 94 insertions, 1 deletions

diff --git a/math/Makefile b/math/Makefile
index 97004f956b..dedd7ee5ea 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 0000000000..5611192823
--- /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 0000000000..5559dd3936
--- /dev/null
+++ b/math/test-fenv-clear.c
@@ -0,0 +1,2 @@
+#define CHECK_CAN_TEST ((void) 0)
+#include <test-fenv-clear-main.c>