[PATCH PR77718]

[Aaron Sawdey]

This patch that Bernd put in PR77718 seems to be fine. Bootstrap and
regtest done on powerpc64le, no new failures. Ok for trunk?

2016-09-28  Bernd Schmidt  <bschmidt@redhat.com>

	* builtins.c (expand_builtin_memcmp): don't swap args unless
	result is only being compared with zero.

Index: builtins.c
===================================================================
--- builtins.c	(revision 240511)
+++ builtins.c	(working copy)
@@ -3707,11 +3707,13 @@ expand_builtin_memcmp (tree exp, rtx tar
 
   by_pieces_constfn constfn = NULL;
 
-Â Â const char *src_str = c_getstr (arg1);
-Â Â if (src_str == NULL)
-Â Â Â Â src_str = c_getstr (arg2);
-Â Â else
-Â Â Â Â std::swap (arg1_rtx, arg2_rtx);
+Â Â const char *src_str = c_getstr (arg2);
+Â Â if (result_eq && src_str == NULL)
+Â Â Â Â {
+Â Â Â Â Â Â src_str = c_getstr (arg1);
+Â Â Â Â Â Â if (src_str != NULL)
+	std::swap (arg1_rtx, arg2_rtx);
+Â Â Â Â }
 
   /* If SRC is a string constant and block move would be done
      by pieces, we can avoid loading the string from memory

-- 
Aaron Sawdey, Ph.D.  acsawdey@linux.vnet.ibm.com
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