[COMMITTED 2.40 2/2] malloc: obscure calloc use in tst-calloc

[Sam James]

Similar to a9944a52c967ce76a5894c30d0274b824df43c7a and
f9493a15ea9cfb63a815c00c23142369ec09d8ce, we need to hide calloc use from
the compiler to accommodate GCC's r15-6566-g804e9d55d9e54c change.

First, include tst-malloc-aux.h, but then use `volatile` variables
for size.

The test passes without the tst-malloc-aux.h change but IMO we want
it there for consistency and to avoid future problems (possibly silent).

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit c3d1dac96bdd10250aa37bb367d5ef8334a093a1)
---
 malloc/tst-calloc.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/malloc/tst-calloc.c b/malloc/tst-calloc.c
index 01f17f9e65..5a8c7ab121 100644
--- a/malloc/tst-calloc.c
+++ b/malloc/tst-calloc.c
@@ -23,6 +23,7 @@
 #include <stdio.h>
 #include <libc-diag.h>
 
+#include "tst-malloc-aux.h"
 
 /* Number of samples per size.  */
 #define N 50000
@@ -94,16 +95,19 @@ random_test (void)
 static void
 null_test (void)
 {
+  /* Obscure allocation size from the compiler.  */
+  volatile size_t max_size = UINT_MAX;
+  volatile size_t zero_size = 0;
   /* If the size is 0 the result is implementation defined.  Just make
      sure the program doesn't crash.  The result of calloc is
      deliberately ignored, so do not warn about that.  */
   DIAG_PUSH_NEEDS_COMMENT;
   DIAG_IGNORE_NEEDS_COMMENT (10, "-Wunused-result");
   calloc (0, 0);
-  calloc (0, UINT_MAX);
-  calloc (UINT_MAX, 0);
-  calloc (0, ~((size_t) 0));
-  calloc (~((size_t) 0), 0);
+  calloc (0, max_size);
+  calloc (max_size, 0);
+  calloc (0, ~((size_t) zero_size));
+  calloc (~((size_t) zero_size), 0);
   DIAG_POP_NEEDS_COMMENT;
 }
 
-- 
2.48.1