https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100077
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2021-04-14
Target| |x86_64-*-*
CC| |matz at gcc dot gnu.org,
| |rguenth at gcc dot gnu.org
Keywords| |missed-optimization
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
The issue is the way the ABI packs things (you are comparing different ABIs as
well), on x86 linux you get things packed in 8-byte quantities which means
v[0] and v[1] go in one xmm reg and v[2] goes in another. This detail becomes
visible too late to elide the stack slot assignment.
There are duplicate related bugreports but there's also no easy fix
forthcoming.
