https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94718
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
--- gcc/fold-const.c.jj 2020-03-31 11:06:14.063512214 +0200
+++ gcc/fold-const.c 2020-04-23 18:39:15.399738420 +0200
@@ -11631,50 +11631,6 @@ fold_binary_loc (location_t loc, enum tr
return omit_one_operand_loc (loc, type, res, arg0);
}
- /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
- if (TREE_CODE (arg0) == BIT_AND_EXPR
- && TREE_CODE (arg1) == BIT_AND_EXPR)
- {
- tree arg00 = TREE_OPERAND (arg0, 0);
- tree arg01 = TREE_OPERAND (arg0, 1);
- tree arg10 = TREE_OPERAND (arg1, 0);
- tree arg11 = TREE_OPERAND (arg1, 1);
- tree itype = TREE_TYPE (arg0);
-
- if (operand_equal_p (arg01, arg11, 0))
- {
- tem = fold_convert_loc (loc, itype, arg10);
- tem = fold_build2_loc (loc, BIT_XOR_EXPR, itype, arg00, tem);
- tem = fold_build2_loc (loc, BIT_AND_EXPR, itype, tem, arg01);
- return fold_build2_loc (loc, code, type, tem,
- build_zero_cst (itype));
- }
- if (operand_equal_p (arg01, arg10, 0))
- {
- tem = fold_convert_loc (loc, itype, arg11);
- tem = fold_build2_loc (loc, BIT_XOR_EXPR, itype, arg00, tem);
- tem = fold_build2_loc (loc, BIT_AND_EXPR, itype, tem, arg01);
- return fold_build2_loc (loc, code, type, tem,
- build_zero_cst (itype));
- }
- if (operand_equal_p (arg00, arg11, 0))
- {
- tem = fold_convert_loc (loc, itype, arg10);
- tem = fold_build2_loc (loc, BIT_XOR_EXPR, itype, arg01, tem);
- tem = fold_build2_loc (loc, BIT_AND_EXPR, itype, tem, arg00);
- return fold_build2_loc (loc, code, type, tem,
- build_zero_cst (itype));
- }
- if (operand_equal_p (arg00, arg10, 0))
- {
- tem = fold_convert_loc (loc, itype, arg11);
- tem = fold_build2_loc (loc, BIT_XOR_EXPR, itype, arg01, tem);
- tem = fold_build2_loc (loc, BIT_AND_EXPR, itype, tem, arg00);
- return fold_build2_loc (loc, code, type, tem,
- build_zero_cst (itype));
- }
- }
-
if (TREE_CODE (arg0) == BIT_XOR_EXPR
&& TREE_CODE (arg1) == BIT_XOR_EXPR)
{
--- gcc/match.pd.jj 2020-03-11 18:33:50.341663648 +0100
+++ gcc/match.pd 2020-04-23 19:17:37.954208051 +0200
@@ -4335,7 +4335,12 @@ (define_operator_list COND_TERNARY
(simplify
(cmp (convert? addr@0) integer_zerop)
(if (tree_single_nonzero_warnv_p (@0, NULL))
- { constant_boolean_node (cmp == NE_EXPR, type); })))
+ { constant_boolean_node (cmp == NE_EXPR, type); }))
+
+ /* (X & C) op (Y & C) into (X ^ Y) & C op 0. */
+ (simplify
+ (cmp (bit_and:cs @0 @2) (bit_and:cs @1 @2))
+ (cmp (bit_and (bit_xor @0 @1) @2) { build_zero_cst (TREE_TYPE (@2)); })))
/* If we have (A & C) == C where C is a power of 2, convert this into
(A & C) != 0. Similarly for NE_EXPR. */
is untested part without testsuite coverage that optimizes the above #c2 third
test the same as #c2 second test. Unsure about :s.
