From: Richard Guenther <rguenther@suse.de>
Date: Wed, 16 Sep 2009 08:50:46 +0000 (+0000)
Subject: re PR tree-optimization/34011 (Memory load is not eliminated from tight vectorized... 
X-Git-Tag: releases/gcc-4.5.0~3492
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4075e7e8dcbb00abdd1f02e54d3328ed86644fbd;p=thirdparty%2Fgcc.git

re PR tree-optimization/34011 (Memory load is not eliminated from tight vectorized loop)

2009-09-16  Richard Guenther  <rguenther@suse.de>

	PR middle-end/34011
	* tree-flow-inline.h (may_be_aliased): Compute readonly variables
	as non-aliased.

	* gcc.dg/tree-ssa/ssa-lim-7.c: New testcase.

From-SVN: r151740
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8eca8bad3bc5..00f964ee401c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2009-09-16  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/34011
+	* tree-flow-inline.h (may_be_aliased): Compute readonly variables
+	as non-aliased.
+
 2009-09-16  DJ Delorie  <dj@redhat.com>
 	    Kaz Kojima  <kkojima@gcc.gnu.org>
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 1f8eb2e855e5..f2ba9735f8ff 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2009-09-16  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/34011
+	* gcc.dg/tree-ssa/ssa-lim-7.c: New testcase.
+
 2009-09-16  DJ Delorie  <dj@redhat.com>
 	    Kaz Kojima  <kkojima@gcc.gnu.org>
 
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-lim-7.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-lim-7.c
new file mode 100644
index 000000000000..f8e15f344860
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-lim-7.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-lim1-details" } */
+
+extern const int srcshift;
+
+void foo (int *srcdata, int *dstdata)
+{
+  int i;
+
+  for (i = 0; i < 256; i++)
+    dstdata[i] = srcdata[i] << srcshift;
+}
+
+/* { dg-final { scan-tree-dump "Moving statement" "lim1" } } */
+/* { dg-final { cleanup-tree-dump "lim1" } } */
diff --git a/gcc/tree-flow-inline.h b/gcc/tree-flow-inline.h
index eef2f4324a99..fdb33378beeb 100644
--- a/gcc/tree-flow-inline.h
+++ b/gcc/tree-flow-inline.h
@@ -616,12 +616,18 @@ is_global_var (const_tree t)
 
 /* Return true if VAR may be aliased.  A variable is considered as
    maybe aliased if it has its address taken by the local TU
-   or possibly by another TU.  */
+   or possibly by another TU and might be modified through a pointer.  */
 
 static inline bool
 may_be_aliased (const_tree var)
 {
-  return (TREE_PUBLIC (var) || DECL_EXTERNAL (var) || TREE_ADDRESSABLE (var));
+  return (TREE_CODE (var) != CONST_DECL
+	  && !((TREE_STATIC (var) || TREE_PUBLIC (var) || DECL_EXTERNAL (var))
+	       && TREE_READONLY (var)
+	       && !TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (var)))
+	  && (TREE_PUBLIC (var)
+	      || DECL_EXTERNAL (var)
+	      || TREE_ADDRESSABLE (var)));
 }