https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92822
rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |rsandifo at gcc dot gnu.org
Assignee|rguenth at gcc dot gnu.org |rsandifo at gcc dot
gnu.org
--- Comment #5 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org>
---
I think this is mostly a target problem. We weren't providing
patterns to extract a 64-bit vector from a 128-bit vector,
despite that being very much a native operation.
Adding those fixes most of the problems. What's left is that:
v4sf_b = VEC_PERM_EXPR <v4sf_a, v4sf_a, { 1, 1, ?, ? }>;
...extract first half of v4sf_b...
gets filled out as:
v4sf_b = VEC_PERM_EXPR <v4sf_a, v4sf_a, { 1, 1, 2, 3 }>;
...extract first half of v4sf_b...
and we never recover from the awkwardness of that permute.
The easiest fix seems to be to extend a partial duplicate
to a full duplicate instead of a partial duplicate followed
by a partial blend.
