Defeat a malloc optimization by declaring things volatile.

malloc/tst-malloc-backtrace.c

@@ -35,8 +35,8 @@ call_free (void *ptr)
 int
 do_test (void)
 {
-  void *ptr1 = malloc (SIZE);
-  void *ptr2 = malloc (SIZE);
+  void *volatile ptr1 = malloc (SIZE);
+  void *volatile ptr2 = malloc (SIZE);
 
   /* Avoid unwanted output to TTY after an expected memory corruption.  */
   ignore_stderr();

malloc/tst-malloc-too-large.c

@@ -69,7 +69,7 @@ test_setup (void)
 static void
 test_large_allocations (size_t size)
 {
-  void * ptr_to_realloc;
+  void *volatile ptr_to_realloc;
 
   test_setup ();
   TEST_VERIFY (malloc (size) == NULL);

malloc/tst-malloc.c

@@ -33,7 +33,7 @@ merror (const char *msg)
 static int
 do_test (void)
 {
-  void *p, *q;
+  void *volatile p, *volatile q;
   int save;
 
   errno = 0;

malloc/tst-mcheck.c

@@ -33,7 +33,7 @@ merror (const char *msg)
 static int
 do_test (void)
 {
-  void *p, *q;
+  void *volatile p, *volatile q;
 
   errno = 0;
 

malloc/tst-valloc.c

@@ -34,7 +34,7 @@ merror (const char *msg)
 static int
 do_test (void)
 {
-  void *p;
+  void *volatile p;
   unsigned long pagesize = getpagesize ();
   unsigned long ptrval;
   int save;