Correct c-torture stkalign test

The test wrongly assumed that a local var will normally not be 64-bit
aligned, causing it to fail on many targets.  So the test needs to
pass if a local var *is* normally 64-bit aligned.

	* gcc.c-torture/execute/stkalign.c: Revise test.

From-SVN: r233407

gcc/testsuite/ChangeLog

+2016-02-14  Alan Modra  <amodra@gmail.com>
+
+	* gcc.c-torture/execute/stkalign.c: Revise test.
+
 2016-02-13  Oleg Endo  <olegendo@gcc.gnu.org>
 
 	PR target/67260

gcc/testsuite/gcc.c-torture/execute/stkalign.c

-/* { dg-xfail-run-if "invalid assumption" { sparc*-*-* && lp64 } "*" "" } */
 /* { dg-options "-fno-inline" } */
+/* Check that stack alignment is not affected by variables not placed
+   on the stack.  */
 
 #include <assert.h>
 
@@ -16,12 +17,28 @@ unsigned test(unsigned n, unsigned p)
   return n ? test(n - 1, x) : (x ^ p);
 }
 
+unsigned test2(unsigned n, unsigned p)
+{
+  static struct { char c; } s;
+  unsigned x;
+
+  assert(__alignof__(s) != ALIGNMENT);
+  asm ("" : "=g" (x), "+m" (s) : "0" (&x));
+
+  return n ? test2(n - 1, x) : (x ^ p);
+}
+
 int main (int argc, char *argv[] __attribute__((unused)))
 {
-  unsigned int x = test(argc, 0);
+  unsigned int x, y;
 
+  x = test(argc, 0);
   x |= test(argc + 1, 0);
   x |= test(argc + 2, 0);
 
-  return !(x & (ALIGNMENT - 1));
+  y = test2(argc, 0);
+  y |= test2(argc + 1, 0);
+  y |= test2(argc + 2, 0);
+
+  return (x & (ALIGNMENT - 1)) == 0 && (y & (ALIGNMENT - 1)) != 0 ? 1 : 0;
 }