benchtests: Reallocate buffers for every test run

Keeping the buffers the same across test runs gives later invocations
the advantage since they access cached data.  Reallocate so that all
test runs are on equal grounds.

	* benchtests/bench-memcmp.c (do_test): Call realloc_buf for
	every test run.

ChangeLog

@@ -1,3 +1,8 @@
+2018-02-02  Siddhesh Poyarekar  <[email protected]>
+
+	* benchtests/bench-memcmp.c (do_test): Call realloc_buf for
+	every test run.
+
 2018-02-01  Joseph Myers  <[email protected]>
 
 	* sysdeps/unix/sysv/linux/syscall-names.list: Update kernel

benchtests/bench-memcmp.c

@@ -110,20 +110,23 @@ do_test (size_t align1, size_t align2, size_t len, int exp_result)
   if (align2 + (len + 1) * CHARBYTES >= page_size)
     return;
 
-  s1 = (CHAR *) (buf1 + align1);
-  s2 = (CHAR *) (buf2 + align2);
+  printf ("Length %4zd, alignment %2zd/%2zd:", len, align1, align2);
 
-  for (i = 0; i < len; i++)
-    s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % CHAR__MAX;
+  FOR_EACH_IMPL (impl, 0)
+    {
+      s1 = (CHAR *) (buf1 + align1);
+      s2 = (CHAR *) (buf2 + align2);
 
-  s1[len] = align1;
-  s2[len] = align2;
-  s2[len - 1] -= exp_result;
+      for (i = 0; i < len; i++)
+	s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % CHAR__MAX;
 
-  printf ("Length %4zd, alignment %2zd/%2zd:", len, align1, align2);
+      s1[len] = align1;
+      s2[len] = align2;
+      s2[len - 1] -= exp_result;
 
-  FOR_EACH_IMPL (impl, 0)
-    do_one_test (impl, s1, s2, len, exp_result);
+      do_one_test (impl, s1, s2, len, exp_result);
+      realloc_bufs ();
+    }
 
   putchar ('\n');
 }