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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.
pull/91/merge
Jan Hubicka 2024-05-15 14:14:27 +02:00
parent ff105c39bd
commit 9b7cad5884
3 changed files with 5 additions and 7 deletions
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5
gcc/alias.cc
View File

@ -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

1
gcc/alias.h
View File

@ -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

6
gcc/tree-ssa-alias.cc
View File

@ -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.