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From: "segher at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/99293] Built-in vec_splat generates sub-optimal code for -mcpu=power10
Date: Sat, 27 Feb 2021 00:52:50 +0000 [thread overview]
Message-ID: <bug-99293-4-odhQMA7peY@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-99293-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99293
Segher Boessenkool <segher at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2021-02-27
Ever confirmed|0 |1
--- Comment #2 from Segher Boessenkool <segher at gcc dot gnu.org> ---
It generates non-optimal code for older CPUs as well (it does two splats
instead of one:
xxpermdi 0,35,35,3 # 7 [c=4 l=4] vsx_extract_v2di/1
xxpermdi 35,0,0,0 # 9 [c=4 l=4] vsx_splat_v2di_reg/0
vrlq 2,2,3
This is because we get things like
Trying 7 -> 9:
7: r117:DI=vec_select(r127:V1TI#0,parallel)
REG_DEAD r127:V1TI
9: r124:V2DI=vec_duplicate(r117:DI)
REG_DEAD r117:DI
Failed to match this instruction:
(set (reg:V2DI 124)
(vec_duplicate:V2DI (vec_select:DI (subreg:V2DI (reg:V1TI 127) 0)
(parallel [
(const_int 0 [0])
]))))
(the patterns we do have use vec_concat instead).
Confirmed.
next prev parent reply other threads:[~2021-02-27 0:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 17:02 [Bug middle-end/99293] New: " munroesj at gcc dot gnu.org
2021-02-26 17:07 ` [Bug middle-end/99293] " munroesj at gcc dot gnu.org
2021-02-27 0:52 ` segher at gcc dot gnu.org [this message]
2021-06-05 5:09 ` [Bug target/99293] " meissner at gcc dot gnu.org
2021-06-05 5:09 ` meissner at gcc dot gnu.org
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