[COMMITTED] Improve PR64242 testcase

[Wilco Dijkstra]

Clear the input array to avoid the testcase accidentally
passing with an incorrect frame pointer.

Committed as obvious.

ChangeLog:
2019-06-17  Wilco Dijkstra  <wdijk...@arm.com>

testsuite/
        PR middle-end/64242
        * gcc.c-torture/execute/pr64242.c: Improve test.

--
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr64242.c 
b/gcc/testsuite/gcc.c-torture/execute/pr64242.c
index 
e6139ede3f34d587ac53d04e286e5d75fd2ca76c..5151f6eef839c0a98c76aeba93fdb800129523a3
 100644
--- a/gcc/testsuite/gcc.c-torture/execute/pr64242.c
+++ b/gcc/testsuite/gcc.c-torture/execute/pr64242.c
@@ -7,6 +7,7 @@ broken_longjmp (void *p)
 {
   void *buf[32];
   __builtin_memcpy (buf, p, 5 * sizeof (void*));
+  __builtin_memset (p, 0, 5 * sizeof (void*));
   /* Corrupts stack pointer...  */
   __builtin_longjmp (buf, 1);
 }