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.

1 files changed, 4 insertions, 0 deletions

diff --git a/sysdeps/x86_64/fpu/fesetenv.c b/sysdeps/x86_64/fpu/fesetenv.c
index 3e3fd8492d..9950aa734a 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;