On Thu, Nov 13, 2025 at 7:45 PM <[email protected]> wrote:
>
> From: Pan Li <[email protected]>
>
> During the match pattern of SAT_U_MUL form 7, we found there is
> a pattern like below:
>
> (nop_convert)(a bit_op (convert b))
>
> which result in the pattern match of SAT_U_MUL complicated and
> unintuitive. According to the suggestion of Richard, we would
> like to simply it to blew:
>
> (convert a) bit_op (convert b)
>
> which is more friendly for reading and bit_op. There are three
> bit_op here, aka bit_ior, bit_and and bit_xor.
>
> gcc/ChangeLog:
>
> * match.pd: Add simplfy to fold outer convert of bit_op
> to inner captures.
So we already have:
/* In GIMPLE, getting rid of 2 conversions for one new results
in smaller IL. */
(simplify
(convert (bitop:cs@2 (nop_convert:s @0) @1))
(if (GIMPLE
&& TREE_CODE (@1) != INTEGER_CST
&& tree_nop_conversion_p (type, TREE_TYPE (@2))
&& types_match (type, @0)
&& !POINTER_TYPE_P (TREE_TYPE (@0))
&& TREE_CODE (TREE_TYPE (@0)) != OFFSET_TYPE)
(bitop @0 (convert @1)))))
It looks very similar. Except the inner is only a nop_convert.
So maybe we should just extend it instead.
At least the new pattern should be right below this one.
Note you do need a few extra checks like the above pattern dealing
with pointer types and offset types too (which was added with
r13-2658-g645ef01a463f15 ).
Thanks,
Andrew Pinski
>
> Signed-off-by: Pan Li <[email protected]>
> ---
> gcc/match.pd | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 3cd9ab1e9b0..8d0d7b907ea 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -3653,6 +3653,25 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> || (wi::eq_p (int_cst_1, itype_max) && wi::eq_p (int_cst_2,
> limit_1)))
> && wi::eq_p (int_cst_3, otype_max)))))))
>
> +/* (nop_convert)(a bit_op (convert b)) => bit_op ((convert a), (convert b))
> */
> +(if (INTEGRAL_TYPE_P (type))
> + (for bit_op (bit_ior bit_and bit_xor)
> + (simplify
> + (convert (bit_op:c @0 (convert @1)))
> + (with
> + {
> + unsigned prec = TYPE_PRECISION (type);
> + tree type_c0 = TREE_TYPE (@0);
> + tree type_c1 = TREE_TYPE (@1);
> + unsigned prec_c0 = TYPE_PRECISION (type_c0);
> + unsigned prec_c1 = TYPE_PRECISION (type_c1);
> + }
> + (if (INTEGRAL_TYPE_P (type_c0)
> + && INTEGRAL_TYPE_P (type_c1)
> + && prec_c1 > prec
> + && prec == prec_c0)
> + (bit_op:type (convert @0) (convert @1)))))))
> +
> /* Saturation mult for unsigned integer. */
> (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type))
> (for mult_op (mult widen_mult)
> --
> 2.43.0
>
