On Wed, 13 Jan 2021, Jakub Jelinek wrote:
> On Wed, Jan 13, 2021 at 08:35:01AM +0100, Richard Biener wrote:
> > I guess you could use
> >
> > (bit_xor (bit_ior @0 @1) (bit_xor! (bit_not! @2) @1))
>
> I wasn't aware of !.
> I had to put it under #if GIMPLE because ! doesn't seem to be implemented
> for GENERIC, but otherwise it works fine.
Ah, true.
> Though, shouldn't I add then :c on bit_xor and bit_ior/bit_and then?
> The rationale for not adding them before was that constants are
> canonicalized to go last, but if we simplify other things, they might not be
> last anymore...
Yeah, that's true.
> Ok for trunk if it passes another bootstrap/regtest?
OK with the missing :c added.
Thanks,
Richard.
> 2021-01-13 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/96691
> * match.pd ((~X | C) ^ D -> (X | C) ^ (~D ^ C),
> (~X & C) ^ D -> (X & C) ^ (D ^ C)): New simplifications if
> (~D ^ C) or (D ^ C) can be simplified.
>
> * gcc.dg/tree-ssa/pr96691.c: New test.
>
> --- gcc/match.pd.jj 2021-01-13 08:01:58.197627154 +0100
> +++ gcc/match.pd 2021-01-13 10:25:32.327321918 +0100
> @@ -947,8 +947,18 @@ (define_operator_list COND_TERNARY
> (bit_ior:c (bit_xor:c@3 @0 @1) (bit_xor:c (bit_xor:c @1 @2) @0))
> (bit_ior @3 @2))
>
> -/* Simplify (~X & Y) to X ^ Y if we know that (X & ~Y) is 0. */
> #if GIMPLE
> +/* (~X | C) ^ D -> (X | C) ^ (~D ^ C) if (~D ^ C) can be simplified. */
> +(simplify
> + (bit_xor (bit_ior:s (bit_not @0) @1) @2)
> + (bit_xor (bit_ior @0 @1) (bit_xor! (bit_not! @2) @1)))
> +
> +/* (~X & C) ^ D -> (X & C) ^ (D ^ C) if (D ^ C) can be simplified. */
> +(simplify
> + (bit_xor (bit_and:s (bit_not @0) @1) @2)
> + (bit_xor (bit_and @0 @1) (bit_xor! @2 @1)))
> +
> +/* Simplify (~X & Y) to X ^ Y if we know that (X & ~Y) is 0. */
> (simplify
> (bit_and (bit_not SSA_NAME@0) INTEGER_CST@1)
> (if (INTEGRAL_TYPE_P (TREE_TYPE (@0))
> --- gcc/testsuite/gcc.dg/tree-ssa/pr96691.c.jj 2021-01-13
> 10:16:45.828331557 +0100
> +++ gcc/testsuite/gcc.dg/tree-ssa/pr96691.c 2021-01-13 10:16:45.828331557
> +0100
> @@ -0,0 +1,21 @@
> +/* PR tree-optimization/96691 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +/* { dg-final { scan-tree-dump-times " \\\| 123;" 1 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times " \\\& 123;" 1 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times " \\\^ -315;" 1 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times " \\\^ 314;" 1 "optimized" } } */
> +/* { dg-final { scan-tree-dump-not " \\\^ 321;" "optimized" } } */
> +/* { dg-final { scan-tree-dump-not " = ~" "optimized" } } */
> +
> +int
> +foo (int x)
> +{
> + return (~x | 123) ^ 321;
> +}
> +
> +int
> +bar (int x)
> +{
> + return (~x & 123) ^ 321;
> +}
>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
