From: Jakub Jelinek <jakub@redhat.com>
Date: Mon, 13 May 2013 07:46:53 +0000 (+0200)
Subject: re PR tree-optimization/57230 (tree-ssa-strlen incorrectly optimizes a strlen to 0)
X-Git-Tag: releases/gcc-4.9.0~5937
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3a60f32bdee43dcadac21f4e51ce0c43d7aa84a3;p=thirdparty%2Fgcc.git

re PR tree-optimization/57230 (tree-ssa-strlen incorrectly optimizes a strlen to 0)

	PR tree-optimization/57230
	* tree-ssa-strlen.c (handle_char_store): Add missing integer_zerop
	check.

	* gcc.dg/strlenopt-23.c: New test.

From-SVN: r198813
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 51deae8e4af5..2d1bbeaeb3a7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2013-05-13  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/57230
+	* tree-ssa-strlen.c (handle_char_store): Add missing integer_zerop
+	check.
+
 2013-05-12  Joern Rennecke  <joern.rennecke@embecosm.com>
 
 	* config/epiphany/epiphany.c (epiphany_init): Check size of
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 424f68707ef5..52ccf1a2653c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2013-05-13  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/57230
+	* gcc.dg/strlenopt-23.c: New test.
+
 2013-05-12  Oleg Endo  <olegendo@gcc.gnu.org>
 
 	PR target/57108
diff --git a/gcc/testsuite/gcc.dg/strlenopt-23.c b/gcc/testsuite/gcc.dg/strlenopt-23.c
new file mode 100644
index 000000000000..75dab2ae0bb9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strlenopt-23.c
@@ -0,0 +1,15 @@
+/* PR tree-optimization/57230 */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#include "strlenopt.h"
+
+int
+main ()
+{
+  char p[] = "hello world";
+  p[0] = (char) (strlen (p) - 1);
+  if (strlen (p) != 11)
+    abort ();
+  return 0;
+}
diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c
index bea0c28ad458..4b6cfda5db2a 100644
--- a/gcc/tree-ssa-strlen.c
+++ b/gcc/tree-ssa-strlen.c
@@ -1703,7 +1703,7 @@ handle_char_store (gimple_stmt_iterator *gsi)
 	       its length may be decreased.  */
 	    adjust_last_stmt (si, stmt, false);
 	}
-      else if (si != NULL)
+      else if (si != NULL && integer_zerop (gimple_assign_rhs1 (stmt)))
 	{
 	  si = unshare_strinfo (si);
 	  si->length = build_int_cst (size_type_node, 0);