[Bug target/96789] x264: sub4x4_dct() improves when vectorization is disabled

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96789

--- Comment #28 from Hongtao.liu <crazylht at gmail dot com> ---

> Probably you can try to tweak it in ix86_add_stmt_cost? when the statement

Yes, it's the place.

> is UB to UH conversion statement, further check if the def of the input UB
> is MEM.

Only if there's no multi-use for UB. More generally, it's quite difficult to
guess later optimizations for the purpose of more accurate vectorization cost
model, :(.