Fix a miscompilation where a reload reg is reused after it has been clobbered.

	* reload1.c (reloads_unique_chain_p): Ensure that r1 is the input for
	r2.

From-SVN: r203596

gcc/ChangeLog

+2013-10-15  Bernd Schmidt  <bernds@codesourcery.com>
+
+	* reload1.c (reloads_unique_chain_p): Ensure that r1 is the input for
+	r2.
+
 2013-10-15  Richard Biener  <rguenther@suse.de>
 
 	* tree-loop-distribution.c (build_empty_rdg): Inline into

gcc/reload1.c

@@ -5560,6 +5560,14 @@ reloads_unique_chain_p (int r1, int r2)
 	    || reg_mentioned_p (rld[r2].in, rld[r1].in)))
     return false;
 
+  /* The following loop assumes that r1 is the reload that feeds r2.  */
+  if (r1 > r2)
+    {
+      int tmp = r2;
+      r2 = r1;
+      r1 = tmp;
+    }
+
   for (i = 0; i < n_reloads; i ++)
     /* Look for input reloads that aren't our two */
     if (i != r1 && i != r2 && rld[i].in)