From: Bill Schmidt <wschmidt@linux.vnet.ibm.com>
Date: Thu, 13 Oct 2016 15:34:22 +0000 (+0000)
Subject: re PR tree-optimization/77937 (ICE: in replace_one_candidate, at gimple-ssa-strength... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=2d4035dcd7b0be8a9edefb9af8121ae0eaabaa7c;p=gcc.git

re PR tree-optimization/77937 (ICE: in replace_one_candidate, at gimple-ssa-strength-reduction.c:3370)

2016-10-13  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR tree-optimization/77937
	* gimple-ssa-strength-reduction.c (analyze_increments): Set cost
	to infinite when we have a pointer with an increment of -1.

From-SVN: r241125
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index dfd16fe0763..7362986db73 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2016-10-13  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	PR tree-optimization/77937
+	* gimple-ssa-strength-reduction.c (analyze_increments): Set cost
+	to infinite when we have a pointer with an increment of -1.
+
 2016-10-13  Thomas Preud'homme  <thomas.preudhomme@arm.com>
 
 	* coretypes.h: Move MEMMODEL_* macros and enum memmodel definition
diff --git a/gcc/gimple-ssa-strength-reduction.c b/gcc/gimple-ssa-strength-reduction.c
index cfa50d34ad0..72862f85144 100644
--- a/gcc/gimple-ssa-strength-reduction.c
+++ b/gcc/gimple-ssa-strength-reduction.c
@@ -2818,6 +2818,11 @@ analyze_increments (slsr_cand_t first_dep, machine_mode mode, bool speed)
 	       || (incr == -1
 		   && !POINTER_TYPE_P (first_dep->cand_type)))
 	incr_vec[i].cost = COST_NEUTRAL;
+
+      /* FIXME: We don't handle pointers with a -1 increment yet.
+         They are usually unprofitable anyway.  */
+      else if (incr == -1 && POINTER_TYPE_P (first_dep->cand_type))
+	incr_vec[i].cost = COST_INFINITE;
       
       /* FORNOW: If we need to add an initializer, give up if a cast from
 	 the candidate's type to its stride's type can lose precision.