https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
Richard Biener changed:
What|Removed |Added
Status|REOPENED|RESOLVED
Resolution|---
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
--- Comment #21 from Marc Glisse ---
(In reply to Matthias Kretz from comment #20)
> The original issue I meant to report is fixed. There are many more missed
> optimizations in the original example, though.
ok, your choice if you prefer to clos
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
--- Comment #20 from Matthias Kretz ---
The original issue I meant to report is fixed. There are many more missed
optimizations in the original example, though.
I.e. https://godbolt.org/z/7P1o3O should compile to:
use_insert_extract():
vmovdqu
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
--- Comment #19 from Marc Glisse ---
(In reply to Matthias Kretz from comment #18)
> FWIW, the issue is resolved on trunk. GCC8.2 still has the missed
> optimization: https://godbolt.org/z/hbgIIi
If I use exactly the testcase from the original d
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
--- Comment #18 from Matthias Kretz ---
FWIW, the issue is resolved on trunk. GCC8.2 still has the missed optimization:
https://godbolt.org/z/hbgIIi
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
Marc Glisse changed:
What|Removed |Added
Status|RESOLVED|REOPENED
Resolution|FIXED
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
Martin Liška changed:
What|Removed |Added
Status|NEW |RESOLVED
CC|
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
Qirun Zhang changed:
What|Removed |Added
CC||helloqirun at gmail dot com
--- Comment #1
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
--- Comment #14 from Marc Glisse ---
Author: glisse
Date: Sat Jul 26 09:00:31 2014
New Revision: 213076
URL: https://gcc.gnu.org/viewcvs?rev=213076&root=gcc&view=rev
Log:
2014-07-26 Marc Glisse
PR target/44551
gcc/
* simplify-rtx.c (
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
--- Comment #13 from Marc Glisse ---
Created attachment 32915
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=32915&action=edit
simplify vec_select(vec_concat)
A simpler/safer version of the patch linked in comment #12 (untested). It
optimi
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
Marc Glisse changed:
What|Removed |Added
CC||glisse at gcc dot gnu.org
--- Com
--- Comment #11 from hjl dot tools at gmail dot com 2010-06-28 19:17
---
Testcase is
[...@gnu-6 44551]$ cat c.c
#include
__m128i
foo (__m256i x, __m128i y)
{
__m256i r = _mm256_insertf128_si256(x, y, 1);
__m128i a = _mm256_extractf128_si256(r, 1);
return a;
}
[...@gnu-6 44551]$
--- Comment #10 from hjl dot tools at gmail dot com 2010-06-28 19:17
---
Here is a small testcase:
[...@gnu-6 44551]$ cat c.s
.file "c.c"
.text
.p2align 4,,15
.globl foo
.type foo, @function
foo:
.LFB798:
.cfi_startproc
pushq %rbp
--- Comment #9 from pinskia at gcc dot gnu dot org 2010-06-18 00:49 ---
(In reply to comment #8)
> Can we use subreg instead of vec_select?
Kinda, you need to do triple subregs, first to an integer mode and then to a
smaller integer mode and then to the other vector mode. subreg on vec
--- Comment #8 from hjl dot tools at gmail dot com 2010-06-18 00:46 ---
Can we use subreg instead of vec_select?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
--- Comment #7 from hjl dot tools at gmail dot com 2010-06-17 22:01 ---
Created an attachment (id=20934)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20934&action=view)
A patch to split cast
Here is a patch to split cast. But it doesn't remove
redundant vinsertf128/vextractf128.
--- Comment #6 from kretz at kde dot org 2010-06-16 21:21 ---
(In reply to comment #4)
> You can also cast 128bit to 256bit with upper 128bit undefined.
If you cast from xmm to ymm after a 128bit instruction coded with VEX prefix
then the upper 128bit are actually guaranteed to be zero.
--- Comment #5 from pinskia at gcc dot gnu dot org 2010-06-16 20:46 ---
(In reply to comment #4)
> You can cast 256bit to 128bit to get the lower 128bit.
This way can be represented using vec_select. And then later on using a split
(after reload) turned into a move.
> You can also cas
--- Comment #4 from hjl dot tools at gmail dot com 2010-06-16 20:42 ---
You can cast 256bit to 128bit to get the lower 128bit. You can also
cast 128bit to 256bit with upper 128bit undefined. If I use union,
it will always generate 2 moves via memory.
--
http://gcc.gnu.org/bugzilla/s
--- Comment #3 from pinskia at gcc dot gnu dot org 2010-06-16 20:00 ---
Well for one, you could have a splitter if the case which_alternative == 0 so
that an reg rename can do its magic.
Also what does UNSPEC_CAST really do? From the looks of it is just a move
which you could use a spl
--- Comment #2 from hjl dot tools at gmail dot com 2010-06-16 19:50 ---
The problem is UNSPEC_CAST. There is no good way to model it.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44551
--- Comment #1 from rguenth at gcc dot gnu dot org 2010-06-16 09:02 ---
This is probably missing combiner patterns in sse.md.
--
rguenth at gcc dot gnu dot org changed:
What|Removed |Added
---
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