[Bug target/114252] Introducing bswapsi reduces code performance

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114252

--- Comment #6 from rguenther at suse dot de <rguenther at suse dot de> ---
> Am 06.03.2024 um 17:12 schrieb gjl at gcc dot gnu.org <gcc-bugzilla@gcc.gnu.org>:
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114252
> 
> --- Comment #5 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
> (In reply to Richard Biener from comment #4)
>> So bswap on a value is just register shuffling, right?
> 
> The point is that there is no need for bswap in the first place, just have a
> look at the code that v13 generates.  It's 4 QI loads and that's it, no
> shuffling required at all.
> 
> But v14 dropped that, and the bswapsi (presumably due to previous flawed tree
> optmizations) is introduced by some tree pass.
> 
> There's nothing the backend can do about it.  So would you explain why you
> think it's a "target" issue?
> 
> Maybe the PR title I used is confusing and does not hit the point?

Why does the target say it has bswapsi then? In which case is that profitable?

> --
> You are receiving this mail because:
> You are on the CC list for the bug.