https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114440
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Blocks| |53947
Last reconfirmed| |2024-03-25
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
It looks like this should be possible, but of course this performs more "weird"
re-association which might be a problem with floating-point (though I don't
know of any lane-reducing ops implemented for FP).
Representing the "scalar" side in the vectorizer IL is tricky though, this
is why the current handling is separated and not integrated with the rest
(so it doesn't compose as you noticed).
Note we lack SLP recognition for dot_prod and sad also because we do not
specify which lanes are combined, so the optabs are a black-box and only
useful when the resulting lanes are reduced.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations
