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

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d0ce117..56e13e8 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+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

diff --git a/gcc/gimple-ssa-strength-reduction.c b/gcc/gimple-ssa-strength-reduction.c
index 82721a9..937a877 100644 (file)
--- a/gcc/gimple-ssa-strength-reduction.c
+++ b/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);