https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80248
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2017-03-29
CC| |jakub at gcc dot gnu.org
Blocks| |53947
Summary|sparse access to Array of |sparse access to Array of
|structures does not |structures does not
|vectorize |vectorize using gathers
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
t.cc:20:17: note: not vectorized: not suitable for gather load _2 = f3[_1].x;
t.cc:20:17: note: bad data references.
that's because vect_check_gather_scatter computes a scale of 12 which isn't
supported by the HW (index _1, scale 12).
It seems to force a SSA name info->offset (_1) and thus doesn't handle
_1 * 3 to make scale == 4 supported. In aos2 you conveniently expose
that as a SSA name yourself.
Looks like we need to split up scale by eventually emitting a multiplication
of the index vector separately.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations
