On Tue, 30 Jun 2015, Marek Polacek wrote:
> This moves a simple optimization. Here it's plain to see how :c
> removes the need to duplicate code to handle commutativity.
>
> I put some more converts into the pattern, but then it's turned
> out that I also need the tree_nop_conversion_p (otherwise we'd
> regress binop-notor2.c that uses booleans).
>
> I did a regtest with the patterns in fold-const.c removed to see
> whether we have some testing for this folding -- and there were
> no regressions, so I had to write a test.
>
> Bootstrapped/regtested on x86_64-linux, ok for trunk?
Ok.
Thanks,
Richard.
> 2015-06-29 Marek Polacek <pola...@redhat.com>
>
> * fold-const.c (fold_binary_loc): Move ~X | X folding ...
> * match.pd: ... here.
>
> * gcc.dg/fold-ior-2.c: New test.
>
> diff --git gcc/fold-const.c gcc/fold-const.c
> index a447452..caba0cf 100644
> --- gcc/fold-const.c
> +++ gcc/fold-const.c
> @@ -10928,24 +10928,6 @@ fold_binary_loc (location_t loc,
>
> case BIT_IOR_EXPR:
> bit_ior:
> - /* ~X | X is -1. */
> - if (TREE_CODE (arg0) == BIT_NOT_EXPR
> - && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0))
> - {
> - t1 = build_zero_cst (type);
> - t1 = fold_unary_loc (loc, BIT_NOT_EXPR, type, t1);
> - return omit_one_operand_loc (loc, type, t1, arg1);
> - }
> -
> - /* X | ~X is -1. */
> - if (TREE_CODE (arg1) == BIT_NOT_EXPR
> - && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
> - {
> - t1 = build_zero_cst (type);
> - t1 = fold_unary_loc (loc, BIT_NOT_EXPR, type, t1);
> - return omit_one_operand_loc (loc, type, t1, arg0);
> - }
> -
> /* Canonicalize (X & C1) | C2. */
> if (TREE_CODE (arg0) == BIT_AND_EXPR
> && TREE_CODE (arg1) == INTEGER_CST
> diff --git gcc/match.pd gcc/match.pd
> index 0cf3d21..5dcbc1a 100644
> --- gcc/match.pd
> +++ gcc/match.pd
> @@ -283,6 +283,12 @@ along with GCC; see the file COPYING3. If not see
> (bit_and @0 integer_zerop@1)
> @1)
>
> +/* ~x | x -> -1 */
> +(simplify
> + (bit_ior:c (convert? @0) (convert? (bit_not @0)))
> + (if (tree_nop_conversion_p (type, TREE_TYPE (@0)))
> + { build_all_ones_cst (type); }))
> +
> /* x ^ x -> 0 */
> (simplify
> (bit_xor @0 @0)
> diff --git gcc/testsuite/gcc.dg/fold-ior-2.c gcc/testsuite/gcc.dg/fold-ior-2.c
> index e69de29..6abac9e 100644
> --- gcc/testsuite/gcc.dg/fold-ior-2.c
> +++ gcc/testsuite/gcc.dg/fold-ior-2.c
> @@ -0,0 +1,47 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O -fdump-tree-cddce1" } */
> +
> +int
> +fn1 (int x)
> +{
> + return ~x | x;
> +}
> +
> +int
> +fn2 (int x)
> +{
> + return x | ~x;
> +}
> +
> +unsigned int
> +fn3 (unsigned int x)
> +{
> + return ~x | x;
> +}
> +
> +unsigned int
> +fn4 (unsigned int x)
> +{
> + return ~x | x;
> +}
> +
> +int
> +fn5 (int x)
> +{
> + return ~x | (unsigned) x;
> +}
> +
> +int
> +fn6 (int x)
> +{
> + return (unsigned) ~x | x;
> +}
> +
> +int
> +fn7 (int x)
> +{
> + return ~(unsigned) x | x;
> +}
> +
> +/* { dg-final { scan-tree-dump-not "~" "cddce1" } } */
> +/* { dg-final { scan-tree-dump-not " \\| " "cddce1" } } */
>
> Marek
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Dilip Upmanyu, Graham
Norton, HRB 21284 (AG Nuernberg)
