re PR tree-optimization/90610 (526.blender_r miscompared on znver1 with -Ofast…

re PR tree-optimization/90610 (526.blender_r miscompared on znver1 with -Ofast -march=native since r271463)

2019-05-27  Richard Biener  <rguenther@suse.de>

	PR middle-end/90610
	* match.pd (vec_perm): Avoid clobbering op0 when not generating
	a bit-insert.

From-SVN: r271652

gcc/ChangeLog

+2019-05-27  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/90610
+	* match.pd (vec_perm): Avoid clobbering op0 when not generating
+	a bit-insert.
+
 2019-05-26  Uroš Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/i386.md (@leave_<mode>): New expander.

gcc/match.pd

@@ -5453,8 +5453,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 		   first vector we only can insert the first elt from
 		   the first vector.  */
 	        at = 0;
-		ins = fold_read_from_vector (cop0, 0);
-	        op0 = op1;
+		if ((ins = fold_read_from_vector (cop0, 0)))
+		  op0 = op1;
 	      }
 	    else
 	      {