[Bug tree-optimization/93771] SLP produces VEC_PERM when should have used vector generation
pinskia at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Mon Feb 17 09:30:00 GMT 2020
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93771
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #2)
> Confirmed. I'm not sure if we should try to "fix" SLP here or rather
> appropriately optimize
>
> v2df tem1 = *(v2df *)&t[0];
> v2df tem2 = *(v2df *)&t[2];
> __builtin_shuffle (tem1, tem2 (v2di) { 0, 3 });
>
> which the user could write itself. forwprop does some related transforms
> splitting loads in "Rewrite loads used only in BIT_FIELD_REF extractions to
> component-wise loads."
I was thinking about originally filing the bug that way but I decided against
it; though I don't remember my reasoning besides I saw SLP not doing it for
unrelated loads.
More information about the Gcc-bugs
mailing list