Upstream-Status: Inappropriate [Backport]
From d0c1a282504a0fa941a9ae22536c73f64d8c5762 Mon Sep 17 00:00:00 2001
From: rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Thu, 21 Apr 2011 14:40:53 +0000
Subject: [PATCH 162/200] 2011-04-21  Richard Guenther  <rguenther@suse.de>

	PR middle-end/48695
	* tree-ssa-alias.c (aliasing_component_refs_p): Compute base
	objects and types here.  Adjust for their offset before
	comparing.

	* g++.dg/torture/pr48695.C: New testcase.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_6-branch@172831 138bc75d-0d04-0410-961f-82ee72b054a4

index e26c75d..3b0e585 100644
new file mode 100644
index 0000000..44e6c77
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr48695.C
@@ -0,0 +1,38 @@
+// { dg-do run }
+
+typedef __SIZE_TYPE__ size_t;
+
+inline void *operator new (size_t, void *__p) throw() { return __p; }
+
+struct _Vector_impl
+{
+  int *_M_start;
+  int *_M_finish;
+  _Vector_impl () :_M_start (0), _M_finish (0) {}
+};
+
+struct vector
+{
+  _Vector_impl _M_impl;
+  int *_M_allocate (size_t __n)
+  {
+    return __n != 0 ? new int[__n] : 0;
+  }
+  void push_back ()
+  {
+    new (this->_M_impl._M_finish) int ();
+    this->_M_impl._M_finish =
+      this->_M_allocate (this->_M_impl._M_finish - this->_M_impl._M_start) + 1;
+  }
+};
+
+int
+main ()
+{
+  for (int i = 0; i <= 1; i++)
+    for (int j = 0; j <= 1; j++)
+      {
+	vector a[2];
+	a[i].push_back ();
+      }
+}
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index bd8953b..8434179 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -594,11 +594,11 @@ same_type_for_tbaa (tree type1, tree type2)
    are the respective alias sets.  */
 
 static bool
-aliasing_component_refs_p (tree ref1, tree type1,
+aliasing_component_refs_p (tree ref1,
 			   alias_set_type ref1_alias_set,
 			   alias_set_type base1_alias_set,
 			   HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
-			   tree ref2, tree type2,
+			   tree ref2,
 			   alias_set_type ref2_alias_set,
 			   alias_set_type base2_alias_set,
 			   HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2,
@@ -610,9 +610,21 @@ aliasing_component_refs_p (tree ref1, tree type1,
        struct A { int i; int j; } *q;
        struct B { struct A a; int k; } *p;
      disambiguating q->i and p->a.j.  */
+  tree base1, base2;
+  tree type1, type2;
   tree *refp;
   int same_p;
 
+  /* Choose bases and base types to search for.  */
+  base1 = ref1;
+  while (handled_component_p (base1))
+    base1 = TREE_OPERAND (base1, 0);
+  type1 = TREE_TYPE (base1);
+  base2 = ref2;
+  while (handled_component_p (base2))
+    base2 = TREE_OPERAND (base2, 0);
+  type2 = TREE_TYPE (base2);
+
   /* Now search for the type1 in the access path of ref2.  This
      would be a common base for doing offset based disambiguation on.  */
   refp = &ref2;
@@ -628,6 +640,8 @@ aliasing_component_refs_p (tree ref1, tree type1,
       HOST_WIDE_INT offadj, sztmp, msztmp;
       get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp);
       offset2 -= offadj;
+      get_ref_base_and_extent (base1, &offadj, &sztmp, &msztmp);
+      offset1 -= offadj;
       return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
     }
   /* If we didn't find a common base, try the other way around.  */
@@ -644,6 +658,8 @@ aliasing_component_refs_p (tree ref1, tree type1,
       HOST_WIDE_INT offadj, sztmp, msztmp;
       get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp);
       offset1 -= offadj;
+      get_ref_base_and_extent (base2, &offadj, &sztmp, &msztmp);
+      offset2 -= offadj;
       return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
     }
 
@@ -805,11 +821,10 @@ indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
       && TREE_CODE (base1) != TARGET_MEM_REF
       && (TREE_CODE (base1) != MEM_REF
 	  || same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1))
-    return aliasing_component_refs_p (ref1, TREE_TYPE (ptrtype1),
+    return aliasing_component_refs_p (ref1,
 				      ref1_alias_set, base1_alias_set,
 				      offset1, max_size1,
-				      ref2, TREE_TYPE
-				              (reference_alias_ptr_type (ref2)),
+				      ref2,
 				      ref2_alias_set, base2_alias_set,
 				      offset2, max_size2, true);
 
@@ -952,10 +967,10 @@ indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
 	  || same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1)
       && (TREE_CODE (base2) != MEM_REF
 	  || same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) == 1))
-    return aliasing_component_refs_p (ref1, TREE_TYPE (ptrtype1),
+    return aliasing_component_refs_p (ref1,
 				      ref1_alias_set, base1_alias_set,
 				      offset1, max_size1,
-				      ref2, TREE_TYPE (ptrtype2),
+				      ref2,
 				      ref2_alias_set, base2_alias_set,
 				      offset2, max_size2, false);
 
-- 
1.7.0.4