i686: Do not raise exception traps on fesetexcept (BZ 30989)

According to ISO C23 (7.6.4.4), fesetexcept is supposed to set
floating-point exception flags without raising a trap (unlike
feraiseexcept, which is supposed to raise a trap if feenableexcept
was called with the appropriate argument).

The flags can be set in the 387 unit or in the SSE unit.  To set
a flag, it is sufficient to do it in the SSE unit, because that is
guaranteed to not trap.  However, on i386 CPUs that have only a
387 unit, set the flags in the 387, as long as this cannot trap.

Checked on i686-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 5 insertions, 18 deletions

diff --git a/sysdeps/x86/fpu/test-fenv-sse-2.c b/sysdeps/x86/fpu/test-fenv-sse-2.c
index f3e820b6ed..7a0503790f 100644
--- a/sysdeps/x86/fpu/test-fenv-sse-2.c
+++ b/sysdeps/x86/fpu/test-fenv-sse-2.c
@@ -22,17 +22,8 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.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;
-}
+#include <cpu-features.h>
+#include <support/check.h>
 
 static uint32_t
 get_sse_mxcsr (void)
@@ -164,13 +155,9 @@ sse_tests (void)
 static int
 do_test (void)
 {
-  if (!have_sse2 ())
-    {
-      puts ("CPU does not support SSE2, cannot test");
-      return 0;
-    }
+  if (!CPU_FEATURE_USABLE (SSE2))
+    FAIL_UNSUPPORTED ("CPU does not support SSE2");
   return sse_tests ();
 }
 
-#define TEST_FUNCTION do_test ()
-#include <test-skeleton.c>
+#include <support/test-driver.c>