https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107647
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot
gnu.org
Priority|P3 |P2
--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
I think the SLP pattern detection doesn't even work with a FMADD, FMSUB combo.
We don't generate FMSUB early, not sure if we could somehow trick us into
folding one with __builtin_fma, maybe __builtin_fma (x, y, -z) would do, I'd
have to check.
So yes, the SLP pattern detection introduces a FMA where none was before
(and then vectorizes it).
I'll fix it.
