http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35290
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
AssignedTo|unassigned at gcc dot |rguenth at gcc dot gnu.org
|gnu.org |
--- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2010-11-10
12:32:16 UTC ---
Well, it's not working on the tree level to make it cheaper:
/* We deliberately stop on clobbering statements and not only on
killing ones to make walking cheaper. Otherwise we can just
continue walking until both stores have equal reference trees. */
while (!stmt_may_clobber_ref_p (temp, gimple_assign_lhs (stmt)));
changing that to
while (!stmt_kills_ref_p (temp, gimple_assign_lhs (stmt)));
will make it work (and slower).
Also needs (possibly unsafe in general if used cross loop iteration)
Index: gcc/tree-ssa-alias.c
===================================================================
--- gcc/tree-ssa-alias.c (revision 166526)
+++ gcc/tree-ssa-alias.c (working copy)
@@ -1577,7 +1577,12 @@ stmt_kills_ref_p_1 (gimple stmt, ao_ref
base = get_ref_base_and_extent (lhs, &offset, &size, &max_size);
/* We can get MEM[symbol: sZ, index: D.8862_1] here,
so base == ref->base does not always hold. */
- if (base == ref->base)
+ if (base == ref->base
+ || (TREE_CODE (base) == MEM_REF
+ && TREE_CODE (ref->base) == MEM_REF
+ && TREE_OPERAND (base, 0) == TREE_OPERAND (ref->base, 0)
+ && tree_int_cst_equal (TREE_OPERAND (base, 1),
+ TREE_OPERAND (ref->base, 1))))
{
/* For a must-alias check we need to be able to constrain
the accesses properly. */
