From: Eric Botcazou <ebotcazou@adacore.com>
Date: Wed, 4 Jan 2012 21:37:11 +0000 (+0000)
Subject: re PR tree-optimization/51624 (Assert_Failure atree.adb:808 during stage 3)
X-Git-Tag: releases/gcc-4.6.3~203
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1140c0387eacda66e51fa2d29f3be3e679bd1533;p=thirdparty%2Fgcc.git

re PR tree-optimization/51624 (Assert_Failure atree.adb:808 during stage 3)

	PR tree-optimization/51624
	* tree-sra.c (build_ref_for_model): When replicating a chain of
	COMPONENT_REFs, stop as soon as the offset would become negative.

From-SVN: r182890
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0b7afad9efde..c9a2654764b1 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2012-01-04  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR tree-optimization/51624
+	* tree-sra.c (build_ref_for_model): When replicating a chain of
+	COMPONENT_REFs, stop as soon as the offset would become negative.
+
 2012-01-04  Richard Guenther  <rguenther@suse.de>
 
 	PR tree-optimization/49651
diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index 756fe74bd525..016c0387d777 100644
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -1472,8 +1472,14 @@ build_ref_for_model (location_t loc, tree base, HOST_WIDE_INT offset,
 
       do {
 	tree field = TREE_OPERAND (expr, 1);
-	offset -= int_bit_position (field);
+	HOST_WIDE_INT bit_pos = int_bit_position (field);
 
+	/* We can be called with a model different from the one associated
+	   with BASE so we need to avoid going up the chain too far.  */
+	if (offset - bit_pos < 0)
+	  break;
+
+	offset -= bit_pos;
 	VEC_safe_push (tree, stack, cr_stack, expr);
 
 	expr = TREE_OPERAND (expr, 0);