re PR middle-end/89008 (O2 and O1 results differ for simple test)

2018-01-31  Bill Schmidt  <wschmidt@linux.ibm.com>

	PR tree-optimization/89008
	* gimple-ssa-strength-reduction.c (slsr_process_mul): Don't
	process anything of the form X * 0.

From-SVN: r268422

gcc/ChangeLog

+2018-01-31  Bill Schmidt  <wschmidt@linux.ibm.com>
+
+	PR tree-optimization/89008
+	* gimple-ssa-strength-reduction.c (slsr_process_mul): Don't
+	process anything of the form X * 0.
+
 2019-01-31  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/89135

gcc/gimple-ssa-strength-reduction.c

@@ -1268,7 +1268,7 @@ slsr_process_mul (gimple *gs, tree rhs1, tree rhs2, bool speed)
       c->next_interp = c2->cand_num;
       c2->first_interp = c->cand_num;
     }
-  else if (TREE_CODE (rhs2) == INTEGER_CST)
+  else if (TREE_CODE (rhs2) == INTEGER_CST && !integer_zerop (rhs2))
     {
       /* Record an interpretation for the multiply-immediate.  */
       c = create_mul_imm_cand (gs, rhs1, rhs2, speed);