On Fri, 14 Mar 2025, Jakub Jelinek wrote:
> Hi!
>
> The following testcase ICEs since r15-8025.
> tree_nop_conversion_p doesn't imply TREE_TYPE (@0) is uselessly convertible
> to type, e.g. they could be INTEGER_TYPEs with the same precision but
> different TYPE_SIGN.
>
> The following patch just adds a convert so that it creates a valid IL
> even in those cases.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
Richard.
> 2025-03-14 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/119287
> * match.pd (((X >> C1) & C2) * (1 << C1) to X & (C2 << C1)): Use
> (convert @0) instead of @0 in the substitution.
>
> * gcc.dg/pr119287.c: New test.
>
> --- gcc/match.pd.jj 2025-03-13 14:05:09.689017389 +0100
> +++ gcc/match.pd 2025-03-14 12:13:02.563169756 +0100
> @@ -5284,7 +5284,7 @@ (define_operator_list SYNC_FETCH_AND_AND
> || tree_int_cst_sgn (@2) >= 0)
> && wi::to_wide (@3) == wi::set_bit_in_zero (shift, prec))
> (with { auto mask = wide_int::from (wi::to_wide (@2), prec, UNSIGNED); }
> - (bit_and @0 { wide_int_to_tree (type, mask << shift); }))))))
> + (bit_and (convert @0) { wide_int_to_tree (type, mask << shift); }))))))
>
> /* ~(~X >> Y) -> X >> Y (for arithmetic shift). */
> (simplify
> --- gcc/testsuite/gcc.dg/pr119287.c.jj 2025-03-14 12:27:37.470247725
> +0100
> +++ gcc/testsuite/gcc.dg/pr119287.c 2025-03-14 12:27:04.367696980 +0100
> @@ -0,0 +1,16 @@
> +/* PR tree-optimization/119287 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fwrapv" } */
> +
> +unsigned a;
> +int b;
> +signed char c, d;
> +
> +void
> +foo (void)
> +{
> + c = a >> 14 & 1;
> + for (; d;)
> + c = 1;
> + b = c << 14;
> +}
>
> 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)
