From: Richard Biener <rguenther@suse.de>
Date: Mon, 25 Apr 2022 08:55:21 +0000 (+0200)
Subject: tree-optimization/105368 - avoid overflow in powi_cost
X-Git-Tag: releases/gcc-10.4.0~107
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ebe6ffee1aa2d819e4fbdf4130e054a33c274b38;p=thirdparty%2Fgcc.git

tree-optimization/105368 - avoid overflow in powi_cost

The following avoids undefined signed overflow when computing
the absolute of the exponent in powi_cost.

2022-04-25  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/105368
	* tree-ssa-math-opts.c (powi_cost): Use absu_hwi.

(cherry picked from commit f0e170f72f8bfaa2a64e1d09ebdfd48f917420f1)
---

diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c
index 4c89fddcfc57..fbaa3deffe39 100644
--- a/gcc/tree-ssa-math-opts.c
+++ b/gcc/tree-ssa-math-opts.c
@@ -1328,7 +1328,7 @@ powi_cost (HOST_WIDE_INT n)
     return 0;
 
   /* Ignore the reciprocal when calculating the cost.  */
-  val = (n < 0) ? -n : n;
+  val = absu_hwi (n);
 
   /* Initialize the exponent cache.  */
   memset (cache, 0, POWI_TABLE_SIZE * sizeof (bool));