re PR tree-optimization/46562 (CCP currently needs iteration for &a[i])

2011-03-24  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/46562
	* tree.c (build_invariant_address): New function.
	* tree.h (build_invariant_address): Declare.
	* tree-dfa.c (get_addr_base_and_unit_offset): Wrap around
	a renamed function moved ...
	* tree-flow-inline.h (get_addr_base_and_unit_offset_1): ... here.
	Take valueization callback parameter.
	* tree-flow.h (gimple_fold_stmt_to_constant): Declare.
	* gimple-fold.h: New file.
	* tree-ssa-ccp.c (ccp_fold): Use gimple_fold_stmt_to_constant_1.
	(ccp_fold, fold_const_aggregate_ref,
	fold_ctor_reference, fold_nonarray_ctor_reference,
	fold_array_ctor_reference, fold_string_cst_ctor_reference,
	get_base_constructor): Move ...
	* gimple-fold.c: ... here.
	(gimple_fold_stmt_to_constant_1): New function
	split out from ccp_fold.  Take a valueization callback parameter.
	Valueize all operands.
	(gimple_fold_stmt_to_constant): New wrapper function.
	(fold_const_aggregate_ref_1): New function split out from
	fold_const_aggregate_ref.  Take a valueization callback parameter.
	(fold_const_aggregate_ref): Wrap fold_const_aggregate_ref_1.
	* tree-ssa-sccvn.c (simplify_binary_expression): Simplify
	invariant POINTER_PLUS_EXPRs to invariant form.
	(vn_valueize): New function.
	(try_to_simplify): Simplify by using gimple_fold_stmt_to_constant.
	* tree-vrp.c (vrp_valueize): New function.
	(vrp_visit_assignment_or_call): Use gimple_fold_stmt_to_constant
	to fold statements to constants.
	* tree-ssa-pre.c (eliminate): Properly guard propagation of
	function declarations.
	* Makefile.in (tree-ssa-sccvn.o, tree-vrp.o, gimple-fold.o,
	tree-ssa-ccp.o): Add gimple-fold.h dependencies.

	* c-c++-common/pr46562-2.c: New testcase.
	* c-c++-common/pr46562.c: Likewise.

From-SVN: r171386

1 files changed, 14 insertions, 0 deletions

diff --git a/gcc/tree.c b/gcc/tree.c
index efa51bd..f9e3f40 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -4013,6 +4013,20 @@ reference_alias_ptr_type (const_tree t)
     return build_pointer_type (TYPE_MAIN_VARIANT (TREE_TYPE (base)));
 }
 
+/* Return an invariant ADDR_EXPR of type TYPE taking the address of BASE
+   offsetted by OFFSET units.  */
+
+tree
+build_invariant_address (tree type, tree base, HOST_WIDE_INT offset)
+{
+  tree ref = fold_build2 (MEM_REF, TREE_TYPE (type),
+			  build_fold_addr_expr (base),
+			  build_int_cst (ptr_type_node, offset));
+  tree addr = build1 (ADDR_EXPR, type, ref);
+  recompute_tree_invariant_for_addr_expr (addr);
+  return addr;
+}
+
 /* Similar except don't specify the TREE_TYPE
    and leave the TREE_SIDE_EFFECTS as 0.
    It is permissible for arguments to be null,