https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88464
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Status|UNCONFIRMED |NEW
Last reconfirmed| |2018-12-12
CC| |jakub at gcc dot gnu.org,
| |rguenth at gcc dot gnu.org
Component|c |tree-optimization
Blocks| |53947
Ever confirmed|0 |1
Known to fail| |9.0
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed. The issue here is the target doesn't advertise scatter:
3901 if (targetm.vectorize.builtin_scatter)
(gdb) n
3902 decl = targetm.vectorize.builtin_scatter (vectype, offtype,
scale);
(gdb)
3905 if (!decl)
(gdb) p decl
$5 = (tree) 0x0
(gdb) p decl
$5 = (tree) 0x0
(gdb) p debug_generic_expr (vectype)
vector(4) double
$6 = void
(gdb) p debug_generic_expr (offtype)
int
$7 = void
(gdb) p scale
$8 = 8
probably because of the "mixup" of 4-byte index and 8 byte store element type.
I'm not sure whether Jakub implemented widening of the index at all.
OTOH when using long for idx it doesn't help. Using -march=knl we get
a little bit further but ultimately fail the same way.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations
