On Fri, 4 Oct 2024, Jennifer Schmitz wrote:
> As in https://gcc.gnu.org/pipermail/gcc-patches/2024-September/663185.html,
> this patch guards the simplification x / y * y == x -> x % y == 0 in
> match.pd for vector types by a check for:
> 1) Support of the mod optab for vectors OR
> 2) Application before vector lowering for non-VL vectors.
>
> The patch was bootstrapped and tested with no regression on
> aarch64-linux-gnu and x86_64-linux-gnu.
> OK for mainline?
- (if (TREE_CODE (TREE_TYPE (@0)) != COMPLEX_TYPE)
+ (if (TREE_CODE (TREE_TYPE (@0)) != COMPLEX_TYPE
+ || (VECTOR_INTEGER_TYPE_P (type)
+ && ((optimize_vectors_before_lowering_p ()
+ && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
+ || target_supports_op_p (type, TRUNC_MOD_EXPR,
+ optab_vector))))
this looks a bit odd, VECTOR_INTEGER_TYPE_P (type) checks the
result type of the comparison. I think the whole condition is
better written as
(if (TREE_CODE (TREE_TYPE (@0)) != COMPLEX_TYPE
&& (!VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (@0)))
|| !target_supports_op_p (TREE_TYPE (@0), TRUNC_DIV_EXPR,
optab_vector)
|| target_supports_op_p (TREE_TYPE (@0), TRUNC_MOD_EXPR,
optab_vector)))
when we have non-vector mode we're before lowering, likewise when
the target doesn't support the division. Even before lowering
we shouldn't replace a supported division (and multiplication)
with an unsupported modulo.
Richard.
> Signed-off-by: Jennifer Schmitz <jschm...@nvidia.com>
>
> gcc/
> PR tree-optimization/116831
> * match.pd: Guard simplification to trunc_mod with check for
> mod optab support.
>
> gcc/testsuite/
> PR tree-optimization/116831
> * gcc.dg/torture/pr116831.c: New test.
>
--
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)
