backport: Since x86 psABIs require the function incoming stack must align at 16 bytes...

Backport r265322 from llvm upstream

Since x86 psABIs require the function incoming stack must align at 16
bytes, child process stack passed to clone should be aligned at 16
bytes.

	PR testsuite/70520
	* c-c++-common/asan/clone-test-1.c (main): Align child process
	stack to 16 bytes.

From-SVN: r235790

gcc/testsuite/ChangeLog

+2016-05-02  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR testsuite/70520
+	* c-c++-common/asan/clone-test-1.c (main): Align child process
+	stack to 16 bytes.
+
 2016-05-02  David Malcolm  <dmalcolm@redhat.com>
 
 	PR c++/62314

gcc/testsuite/c-c++-common/asan/clone-test-1.c

@@ -25,7 +25,7 @@ volatile int zero = 0;
 int main(int argc, char **argv) {
   int i;
   const int kStackSize = 1 << 20;
-  char child_stack[kStackSize + 1];
+  char __attribute__((aligned(16))) child_stack[kStackSize + 1];
   char *sp = child_stack + kStackSize;  /* Stack grows down. */
   printf("Parent: %p\n", sp);
   pid_t clone_pid = clone(Child, sp, CLONE_FILES | CLONE_VM, NULL, 0, 0, 0);