On Tue, 11 May 2021, Jakub Jelinek wrote:
> On Thu, May 06, 2021 at 09:42:41PM +0200, Marc Glisse wrote:
> > We can probably do it in 2 steps, first something like
> >
> > (for cmp (eq ne)
> > (simplify
> > (cmp (bit_and:c @0 @1) @0)
> > (cmp (@0 (bit_not! @1)) { build_zero_cst (TREE_TYPE (@0)); })))
> >
> > to get rid of the double use, and then simplify X&C==0 to X<=~C if C is a
> > mask 111...000 (I thought we already had a function to detect such masks, or
> > the 000...111, but I can't find them anymore).
>
> Ok, here is the first step then.
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> Or should it have cmp:c too given that == and != are commutative too?
I think so. OK with that change.
Richard.
> 2021-05-11 Jakub Jelinek <ja...@redhat.com>
> Marc Glisse <marc.gli...@inria.fr>
>
> PR tree-optimization/94589
> * match.pd ((X & Y) == Y -> (X & ~Y) == 0,
> (X | Y) == Y -> (X & ~Y) == 0): New GIMPLE simplifications.
>
> * gcc.dg/tree-ssa/pr94589-1.c: New test.
>
> --- gcc/match.pd.jj 2021-04-27 14:46:56.583716888 +0200
> +++ gcc/match.pd 2021-05-10 22:31:49.726870421 +0200
> @@ -4764,6 +4764,18 @@ (define_operator_list COND_TERNARY
> (cmp:c (bit_xor:c @0 @1) @0)
> (cmp @1 { build_zero_cst (TREE_TYPE (@1)); }))
>
> +#if GIMPLE
> + /* (X & Y) == X becomes (X & ~Y) == 0. */
> + (simplify
> + (cmp (bit_and:c @0 @1) @0)
> + (cmp (bit_and @0 (bit_not! @1)) { build_zero_cst (TREE_TYPE (@0)); }))
> +
> + /* (X | Y) == Y becomes (X & ~Y) == 0. */
> + (simplify
> + (cmp (bit_ior:c @0 @1) @1)
> + (cmp (bit_and @0 (bit_not! @1)) { build_zero_cst (TREE_TYPE (@0)); }))
> +#endif
> +
> /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
> (simplify
> (cmp (convert?@3 (bit_xor @0 INTEGER_CST@1)) INTEGER_CST@2)
> --- gcc/testsuite/gcc.dg/tree-ssa/pr94589-1.c.jj 2021-05-10
> 22:36:10.574130179 +0200
> +++ gcc/testsuite/gcc.dg/tree-ssa/pr94589-1.c 2021-05-10 22:36:17.789054362
> +0200
> @@ -0,0 +1,21 @@
> +/* PR tree-optimization/94589 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +
> +int
> +foo (int x)
> +{
> + return (x & 23) == x;
> +/* { dg-final { scan-tree-dump " & -24;" "optimized" } } */
> +/* { dg-final { scan-tree-dump-not " & 23;" "optimized" } } */
> +/* { dg-final { scan-tree-dump " == 0" "optimized" } } */
> +}
> +
> +int
> +bar (int x)
> +{
> + return (x | 137) != 137;
> +/* { dg-final { scan-tree-dump " & -138;" "optimized" } } */
> +/* { dg-final { scan-tree-dump-not " \\| 137;" "optimized" } } */
> +/* { dg-final { scan-tree-dump " != 0" "optimized" } } */
> +}
>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
