public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug middle-end/99668] New: Converting argument _Complex double to double vector causes STLF stall
@ 2021-03-19 13:36 rguenth at gcc dot gnu.org
2023-05-15 7:02 ` [Bug middle-end/99668] " pinskia at gcc dot gnu.org
0 siblings, 1 reply; 2+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-03-19 13:36 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99668
Bug ID: 99668
Summary: Converting argument _Complex double to double vector
causes STLF stall
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: rguenth at gcc dot gnu.org
Target Milestone: ---
Consider
_Complex double a, b;
typedef double v2df __attribute__((vector_size(16)));
v2df foo (_Complex double x)
{
return *(v2df *)&x;
}
which on GIMPLE is represented as the simple
v2df foo (complex double x)
{
v2df _2;
_2 = VIEW_CONVERT_EXPR<v2df>(x_3(D));
return _2;
}
but since on x86_64 _Complex double are passed in %xmm0 and %xmm1 we end up
with spilling x to the stack:
foo:
.LFB0:
.cfi_startproc
movsd %xmm0, -24(%rsp)
movsd %xmm1, -16(%rsp)
movupd -24(%rsp), %xmm0
ret
Ideally GIMPLE would know that a V_C_E isn't a good representation here
but improving RTL expansion should be possible as well. We expand
x_3(D) to (concat:DC ...) but the V_C_E expansion path misses special-casing
of this. The MEM_REF expansion code can deal with this so eventually
splitting out parts of that support is possible.
In the end we want a simple
movlhps %xmm1, %xmm0
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug middle-end/99668] Converting argument _Complex double to double vector causes STLF stall
2021-03-19 13:36 [Bug middle-end/99668] New: Converting argument _Complex double to double vector causes STLF stall rguenth at gcc dot gnu.org
@ 2023-05-15 7:02 ` pinskia at gcc dot gnu.org
0 siblings, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-05-15 7:02 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99668
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Last reconfirmed| |2023-05-15
Keywords| |missed-optimization
Severity|normal |enhancement
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
.
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2023-05-15 7:02 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-03-19 13:36 [Bug middle-end/99668] New: Converting argument _Complex double to double vector causes STLF stall rguenth at gcc dot gnu.org
2023-05-15 7:02 ` [Bug middle-end/99668] " pinskia at gcc dot gnu.org
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).