From: Volker Reichelt <reichelt@igpm.rwth-aachen.de>
Date: Fri, 10 Dec 2004 17:25:07 +0000 (+0000)
Subject: re PR rtl-optimization/16536 (Incorrect __restrict__ optimization in -O2)
X-Git-Tag: releases/gcc-3.3.6~191
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d3c123ff95c66abb7c73b60990e9e6bdf5c033ed;p=thirdparty%2Fgcc.git

re PR rtl-optimization/16536 (Incorrect __restrict__ optimization in -O2)

	PR rtl-optimization/16536
	Backport from mainline:
	2004-06-25  Mark Mitchell  <mark@codesourcery.com>
	* alias.c (get_alias_set): Adjust setting of
	DECL_POINTER_ALIAS_SET for pointers to aggregates.

	* gcc.c-torture/execute/restrict-1.c: New test.

From-SVN: r91999
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 47caee0b9705..05f9b6cbce5c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2004-12-10  Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
+
+	PR rtl-optimization/16536
+	Backport from mainline:
+	2004-06-25  Mark Mitchell  <mark@codesourcery.com>
+	* alias.c (get_alias_set): Adjust setting of
+	DECL_POINTER_ALIAS_SET for pointers to aggregates.
+
 2004-12-09  Richard Henderson  <rth@redhat.com>
 
 	PR target/17025
diff --git a/gcc/alias.c b/gcc/alias.c
index abc98de7557a..75ac89d065b7 100644
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -508,6 +508,8 @@ get_alias_set (t)
 	      /* If we haven't computed the actual alias set, do it now.  */
 	      if (DECL_POINTER_ALIAS_SET (decl) == -2)
 		{
+		  tree pointed_to_type = TREE_TYPE (TREE_TYPE (decl));
+
 		  /* No two restricted pointers can point at the same thing.
 		     However, a restricted pointer can point at the same thing
 		     as an unrestricted pointer, if that unrestricted pointer
@@ -516,11 +518,22 @@ get_alias_set (t)
 		     alias set for the type pointed to by the type of the
 		     decl.  */
 		  HOST_WIDE_INT pointed_to_alias_set
-		    = get_alias_set (TREE_TYPE (TREE_TYPE (decl)));
+		    = get_alias_set (pointed_to_type);
 
 		  if (pointed_to_alias_set == 0)
 		    /* It's not legal to make a subset of alias set zero.  */
-		    ;
+		    DECL_POINTER_ALIAS_SET (decl) = 0;
+		  else if (AGGREGATE_TYPE_P (pointed_to_type))
+		    /* For an aggregate, we must treat the restricted
+		       pointer the same as an ordinary pointer.  If we
+		       were to make the type pointed to by the
+		       restricted pointer a subset of the pointed-to
+		       type, then we would believe that other subsets
+		       of the pointed-to type (such as fields of that
+		       type) do not conflict with the type pointed to
+		       by the restricted pointer.   */
+		    DECL_POINTER_ALIAS_SET (decl)
+		      = pointed_to_alias_set;
 		  else
 		    {
 		      DECL_POINTER_ALIAS_SET (decl) = new_alias_set ();
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9f9958a91afe..f9d369063b21 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2004-12-10  Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
+
+	PR rtl-optimization/16536
+	* gcc.c-torture/execute/restrict-1.c: New test.
+
 2004-12-09  Nathan Sidwell  <nathan@codesourcery.com>
 
 	PR c++/16681