From: Shu-Chun Weng <scw@google.com>
Date: Mon, 3 May 2021 23:12:44 +0000 (-0700)
Subject: More aggressively prevent a buffer from being optimized out
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=df64d523104d05a17c9ef66345077154588a5424;p=thirdparty%2Fglibc.git

More aggressively prevent a buffer from being optimized out

The volatile global variable was first introduced in e86f9654c. I have
noticed the compiler still optimizing the buffer out on AArch64
presumably because the assignment is after all other observable
behaviors so it's still valid to eliminate it.
---

diff --git a/string/tst-xbzero-opt.c b/string/tst-xbzero-opt.c
index e9c411b2ef5..4f16c4d6784 100644
--- a/string/tst-xbzero-opt.c
+++ b/string/tst-xbzero-opt.c
@@ -119,17 +119,17 @@ static void
 setup_no_clear (void)
 {
   unsigned char buf[TEST_BUFFER_SIZE];
-  prepare_test_buffer (buf);
   vol_glob = buf;
+  prepare_test_buffer (buf);
 }
 
 static void
 setup_ordinary_clear (void)
 {
   unsigned char buf[TEST_BUFFER_SIZE];
+  vol_glob = buf;
   prepare_test_buffer (buf);
   memset (buf, 0, TEST_BUFFER_SIZE);
-  vol_glob = buf;
 }
 
 static void