Avoid pointer compares on TYPE_MAIN_VARIANT in TBAA

while building more testcases for ipa-icf I noticed that there are two places
in aliasing code where we still compare TYPE_MAIN_VARIANT for pointer equality.
This is not good idea for LTO since type merging may not happen for example
when in one unit pointed to type is forward declared while in other it is fully
defined.  We have same_type_for_tbaa for that.

Bootstrapped/regtested x86_64-linux, OK?

gcc/ChangeLog:

	* alias.cc (reference_alias_ptr_type_1): Use view_converted_memref_p.
	* alias.h (view_converted_memref_p): Declare.
	* tree-ssa-alias.cc (view_converted_memref_p): Export.
	(ao_compare::compare_ao_refs): Use same_type_for_tbaa.

diff --git a/gcc/alias.cc b/gcc/alias.cc
index 808e2095d9b482c5996d77eabbc15d7e26464e4b..853e84d7439a2a27ad07682f209e8e42d11be813 100644 (file)
--- a/gcc/alias.cc
+++ b/gcc/alias.cc
@@ -770,10 +770,7 @@ reference_alias_ptr_type_1 (tree *t)
   /* If the innermost reference is a MEM_REF that has a
      conversion embedded treat it like a VIEW_CONVERT_EXPR above,
      using the memory access type for determining the alias-set.  */
-  if (TREE_CODE (inner) == MEM_REF
-      && (TYPE_MAIN_VARIANT (TREE_TYPE (inner))
-         != TYPE_MAIN_VARIANT
-              (TREE_TYPE (TREE_TYPE (TREE_OPERAND (inner, 1))))))
+  if (view_converted_memref_p (inner))
     {
       tree alias_ptrtype = TREE_TYPE (TREE_OPERAND (inner, 1));
       /* Unless we have the (aggregate) effective type of the access

diff --git a/gcc/alias.h b/gcc/alias.h
index f8d93e8b5f4c58c261c4b84dc8a2f95a030acfc0..36095f0bf736e2d56cc8e1cde1c0f36bd382a0ca 100644 (file)
--- a/gcc/alias.h
+++ b/gcc/alias.h
@@ -41,6 +41,7 @@ bool alias_ptr_types_compatible_p (tree, tree);
 int compare_base_decls (tree, tree);
 bool refs_same_for_tbaa_p (tree, tree);
 bool mems_same_for_tbaa_p (rtx, rtx);
+bool view_converted_memref_p (tree);
 
 /* This alias set can be used to force a memory to conflict with all
    other memories, creating a barrier across which no memory reference

diff --git a/gcc/tree-ssa-alias.cc b/gcc/tree-ssa-alias.cc
index 374ba04e6fd09a25ea70ede8655bbf5b34571360..96301bbde7fa1af65712bd91ab0e7f6800fbcdd1 100644 (file)
--- a/gcc/tree-ssa-alias.cc
+++ b/gcc/tree-ssa-alias.cc
@@ -2049,7 +2049,7 @@ decl_refs_may_alias_p (tree ref1, tree base1,
    which is done by ao_ref_base and thus one extra walk
    of handled components is needed.  */
 
-static bool
+bool
 view_converted_memref_p (tree base)
 {
   if (TREE_CODE (base) != MEM_REF && TREE_CODE (base) != TARGET_MEM_REF)
@@ -4330,8 +4330,8 @@ ao_compare::compare_ao_refs (ao_ref *ref1, ao_ref *ref2,
   else if ((end_struct_ref1 != NULL) != (end_struct_ref2 != NULL))
     return flags | ACCESS_PATH;
   if (end_struct_ref1
-      && TYPE_MAIN_VARIANT (TREE_TYPE (end_struct_ref1))
-        != TYPE_MAIN_VARIANT (TREE_TYPE (end_struct_ref2)))
+      && same_type_for_tbaa (TREE_TYPE (end_struct_ref1),
+                            TREE_TYPE (end_struct_ref2)) != 1)
     return flags | ACCESS_PATH;
 
   /* Now compare all handled components of the access path.