https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87664
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |jakub at gcc dot gnu.org
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
This is because the last invariant motion pass happens before register
allocation, and at that point this single expression is represented by a pseudo
register (reg/f: DI 19 frame), and that isn't considered to be something that
should be hoisted before the loop. During register allocation the frame pseudo
gets replaced by something different, like %rsp + constant or %rbp + constant,
and at that point we might need to reconsider that. On the other side, we
might hoist frame + constant even if in the and that ends up being say %rbp
itself or %rsp. I think we have a dup for this somewhere.
