From: Bill Schmidt <wschmidt@linux.ibm.com>
Date: Thu, 31 Jan 2019 21:55:45 +0000 (+0000)
Subject: backport: re PR middle-end/89008 (O2 and O1 results differ for simple test)
X-Git-Tag: releases/gcc-7.5.0~623
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=16d6c1df7281105f9fdff4bec7950807df93f97d;p=thirdparty%2Fgcc.git

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

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

	Backport from mainline
	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: r268431
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b74d9750b18e..954632209aac 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2018-01-31  Bill Schmidt  <wschmidt@linux.ibm.com>
+
+	Backport from mainline
+	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>
 
 	Backport from mainline
diff --git a/gcc/gimple-ssa-strength-reduction.c b/gcc/gimple-ssa-strength-reduction.c
index ed089200e5b9..08bba54fc019 100644
--- a/gcc/gimple-ssa-strength-reduction.c
+++ b/gcc/gimple-ssa-strength-reduction.c
@@ -1220,7 +1220,7 @@ slsr_process_mul (gimple *gs, tree rhs1, tree rhs2, bool speed)
       c->next_interp = c2->cand_num;
       c2->first_interp = c->cand_num;
     }
-  else
+  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);