On Wed, 6 Mar 2024, Jakub Jelinek wrote:
> On Wed, Mar 06, 2024 at 11:45:42AM +0100, Richard Biener wrote:
> > OK, though feel free to add ARG_UNUSED to 'captures' as well.
>
> Ok, done below.
>
> > I think the INTEGRAL_TYPE_P should be redundant - the pattern
> > should work for vectors and complex as well (with integer components
> > which integer_zerop constrains).
>
> Guess you're right. I think it is correct as is for both complex and
> int vector, while float etc. shouldn't appear there because of the
> integer_zerop and pointer because we don't do multiplication on pointer
> types.
>
> That said, it won't really actually match the vector int case actually
> emitted, where we have a VEC_COND_EXPR, added those as new patterns.
> And it doesn't match what is emitted for _Complex, though I think it
> isn't that important to simplify that.
> _Complex int
> freddy (_Complex int x)
> {
> return x * !x;
> }
>
> _Complex int
> garply (_Complex int x)
> {
> return x * (x == 0);
> }
>
> results in original in:
> return COMPLEX_EXPR <REALPART_EXPR <SAVE_EXPR <x>> == 0 && IMAGPART_EXPR
> <SAVE_EXPR <x>> == 0, 0> * x;
> and
> return (x == __complex__ (0, 0) ? __complex__ (1, 0) : __complex__ (0, 0))
> * x;
> but after gimplification it is already something that is really
> too hard to optimize.
>
> So, is the following still ok if it passes bootstrap/regtest?
OK.
Thanks,
Richard.
> 2024-03-06 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/114009
> * genmatch.cc (decision_tree::gen): Emit ARG_UNUSED for captures
> argument even for GENERIC, not just for GIMPLE.
> * match.pd (a * !a -> 0): New simplifications.
>
> * gcc.dg/tree-ssa/pr114009.c: New test.
>
> --- gcc/genmatch.cc.jj 2024-02-26 10:09:16.594613314 +0100
> +++ gcc/genmatch.cc 2024-03-06 13:47:35.001458638 +0100
> @@ -4071,7 +4071,7 @@ decision_tree::gen (vec <FILE *> &files,
> for (unsigned i = 0;
> i < as_a <expr *>(s->s->s->match)->ops.length (); ++i)
> fp_decl (f, " tree ARG_UNUSED (_p%d),", i);
> - fp_decl (f, " tree *captures");
> + fp_decl (f, " tree *ARG_UNUSED (captures)");
> }
> for (unsigned i = 0; i < s->s->s->for_subst_vec.length (); ++i)
> {
> --- gcc/match.pd.jj 2024-03-06 09:34:36.608271525 +0100
> +++ gcc/match.pd 2024-03-06 13:58:27.400588289 +0100
> @@ -1219,6 +1219,17 @@ (define_operator_list SYNC_FETCH_AND_AND
> && tree_nop_conversion_p (type, TREE_TYPE (@1)))
> (lshift @0 @2)))
>
> +/* Fold a * !a into 0. */
> +(simplify
> + (mult:c @0 (convert? (eq @0 integer_zerop)))
> + { build_zero_cst (type); })
> +(simplify
> + (mult:c @0 (vec_cond (eq @0 integer_zerop) @1 integer_zerop))
> + { build_zero_cst (type); })
> +(simplify
> + (mult:c @0 (vec_cond (ne @0 integer_zerop) integer_zerop @1))
> + { build_zero_cst (type); })
> +
> /* Shifts by precision or greater result in zero. */
> (for shift (lshift rshift)
> (simplify
> --- gcc/testsuite/gcc.dg/tree-ssa/pr114009.c.jj 2024-03-06
> 13:44:33.481924326 +0100
> +++ gcc/testsuite/gcc.dg/tree-ssa/pr114009.c 2024-03-06 14:04:09.724918390
> +0100
> @@ -0,0 +1,33 @@
> +/* PR tree-optimization/114009 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -Wno-psabi -fdump-tree-forwprop1" } */
> +/* { dg-final { scan-tree-dump-times " return 0;" 3 "forwprop1" } } */
> +/* { dg-final { scan-tree-dump-times " (?:return|<retval> =) { 0, 0, 0, 0
> };" 1 "forwprop1" } } */
> +
> +int
> +foo (int x)
> +{
> + x = (x / 2) * 2;
> + return (!x) * x;
> +}
> +
> +int
> +bar (int x, int y)
> +{
> + (void) x;
> + return y * !y;
> +}
> +
> +unsigned long long
> +baz (unsigned long long x)
> +{
> + return (!x) * x;
> +}
> +
> +typedef int V __attribute__((vector_size (4 * sizeof (int))));
> +
> +V
> +qux (V x)
> +{
> + return x * (x == 0);
> +}
>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
