Fix FPU context handling in getcontext on x86-64.

fnstenv on x86-64 seems to clear the state.  Work around.

1 files changed, 48 insertions, 0 deletions

diff --git a/stdlib/bug-getcontext.c b/stdlib/bug-getcontext.c
new file mode 100644
index 0000000000..745aa1f207
--- /dev/null
+++ b/stdlib/bug-getcontext.c
@@ -0,0 +1,48 @@
+/* BZ 12420 */
+
+#include <errno.h>
+#include <fenv.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <ucontext.h>
+
+static int
+do_test (void)
+{
+  int except_mask =  FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW;
+  int status = feenableexcept (except_mask);
+
+  except_mask = fegetexcept ();
+  if (except_mask == -1)
+    {
+      printf("\nBefore getcontext(): fegetexcept returned: %d\n",
+	     except_mask);
+      return 1;
+    }
+
+  ucontext_t ctx;
+  status = getcontext(&ctx);
+  if (status)
+    {
+      printf("\ngetcontext failed, errno: %d.\n", errno);
+      return 1;
+    }
+
+  printf ("\nDone with getcontext()!\n");
+  fflush (NULL);
+
+  int mask = fegetexcept ();
+  if (mask != except_mask)
+    {
+      printf("\nAfter getcontext(): fegetexcept returned: %d, expected: %d.\n",
+	     mask, except_mask);
+      return 1;
+    }
+
+  printf("\nAt end fegetexcept() returned %d, expected: %d.\n",
+	 mask, except_mask);
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"