On Tue, Jan 13, 2026 at 12:07 PM Jeffrey Law <[email protected]>
wrote:
>
>
> On 1/13/2026 11:39 AM, Pengxuan Zheng wrote:
>
>
>> >
>> > +/* Fold (X >> C) != 0 into X < 0 if C is one less than the width
>> > + of X. Similarly fold (X >> C) == 0 into X >= 0. */
>> > +(for neeq (ne eq)
>> > + ltge (lt ge)
>> > + (simplify
>> > + (neeq
>> > + (rshift@2 @0 INTEGER_CST@1)
>> > + integer_zerop)
>> > + (with { tree itype = signed_type_for (TREE_TYPE (@0)); }
>> > + /* Make sure to transform vector compares only to supported
>> > + ones or from unsupported ones and check that only after
>> > + IPA so offloaded code is handled correctly in this regard. */
>> > + (if (wi::to_wide (@1) == element_precision (itype) - 1
>> > + && (!VECTOR_TYPE_P (itype)
>> > + || (cfun
>> > + && cfun->after_inlining
>> > + && VECTOR_BOOLEAN_TYPE_P (type)
>> > + && (expand_vec_cmp_expr_p (itype, type, ltge)
>> > + || !expand_vec_cmp_expr_p (TREE_TYPE (@2),
>> > + type, neeq)))))
>> > + (ltge (convert:itype @0) { build_zero_cst (itype); })))))
>> > +
>> So in the PR Richi said the condition ought to be
>> canonicalize_math_after_vectorization_p; this seems to check something
>> meaningfully different (after_inlining). Can you explain why you ended
>> up using the after_inlining test rather than the after_vectorization test?
>>
>
> Yes, Jeff, Richard initially suggested to use
> canonicalize_math_after_vectorization_p,
> but in his latest patch he changed the checks to after_inlining instead
> (
> https://gcc.gnu.org/cgit/gcc/commit/?id=ae0cdb01b08fb4929ef17c534f86cd9fae78e799
> ).
> Therefore, I updated the checks here to align with Richard's latest
> implementation.
>
> Ah, perfect. In that case this is OK for the trunk, go ahead and push it.
>
> Thanks!
> jeff
>
Thanks, Jeff. Pushed as r16-6753-g8d5eb4f6c1f248340f12adbe76882c3615343e8b.
Pengxuan
