This moves &X ==/!= ptr comparison folding which triggers surprisingly
often.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2015-06-29 Richard Biener <rguent...@suse.de>
* genmatch.c (add_operator): Treat ADDR_EXPR as atom.
* fold-const.c (fold_binary_loc): Move &A - &B simplification
via ptr_difference_const ...
* match.pd: ... here.
When matching (X ^ Y) == Y also match with swapped operands.
Index: gcc/genmatch.c
===================================================================
--- gcc/genmatch.c (revision 225007)
+++ gcc/genmatch.c (working copy)
@@ -324,6 +324,9 @@ add_operator (enum tree_code code, const
/* And allow CONSTRUCTOR for vector initializers. */
&& !(code == CONSTRUCTOR))
return;
+ /* Treat ADDR_EXPR as atom, thus don't allow matching its operand. */
+ if (code == ADDR_EXPR)
+ nargs = 0;
operator_id *op = new operator_id (code, id, nargs, tcc);
id_base **slot = operators->find_slot_with_hash (op, op->hashval, INSERT);
if (*slot)
Index: gcc/fold-const.c
===================================================================
--- gcc/fold-const.c (revision 225007)
+++ gcc/fold-const.c (working copy)
@@ -10618,16 +10562,6 @@ fold_binary_loc (location_t loc,
fold_convert_loc (loc, type,
negate_expr (arg1)));
- /* Try folding difference of addresses. */
- {
- HOST_WIDE_INT diff;
-
- if ((TREE_CODE (arg0) == ADDR_EXPR
- || TREE_CODE (arg1) == ADDR_EXPR)
- && ptr_difference_const (arg0, arg1, &diff))
- return build_int_cst_type (type, diff);
- }
-
/* Fold &a[i] - &a[j] to i-j. */
if (TREE_CODE (arg0) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (arg0, 0)) == ARRAY_REF
Index: gcc/match.pd
===================================================================
*** gcc/match.pd (revision 225007)
--- gcc/match.pd (working copy)
*************** (define_operator_list swapped_tcc_compar
*** 545,550 ****
--- 545,565 ----
(with { tree algn = wide_int_to_tree (TREE_TYPE (@0), wi::bit_not (@1)); }
(bit_and @0 { algn; })))
+ /* Try folding difference of addresses. */
+ (simplify
+ (minus (convert ADDR_EXPR@0) (convert @1))
+ (if (tree_nop_conversion_p (type, TREE_TYPE (@0)))
+ (with { HOST_WIDE_INT diff; }
+ (if (ptr_difference_const (@0, @1, &diff))
+ { build_int_cst_type (type, diff); }))))
+ (simplify
+ (minus (convert @0) (convert ADDR_EXPR@1))
+ (if (tree_nop_conversion_p (type, TREE_TYPE (@0)))
+ (with { HOST_WIDE_INT diff; }
+ (if (ptr_difference_const (@0, @1, &diff))
+ { build_int_cst_type (type, diff); }))))
+
+
/* We can't reassociate at all for saturating types. */
(if (!TYPE_SATURATING (type))
*************** (define_operator_list swapped_tcc_compar
*** 1229,1235 ****
/* (X ^ Y) == Y becomes X == 0.
Likewise (X ^ Y) == X becomes Y == 0. */
(simplify
! (cmp (bit_xor:c @0 @1) @0)
(cmp @1 { build_zero_cst (TREE_TYPE (@1)); }))
/* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
--- 1244,1250 ----
/* (X ^ Y) == Y becomes X == 0.
Likewise (X ^ Y) == X becomes Y == 0. */
(simplify
! (cmp:c (bit_xor:c @0 @1) @0)
(cmp @1 { build_zero_cst (TREE_TYPE (@1)); }))
/* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
