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* [Bug target/94395] New: Powerpc suboptimal 64-bit constant generation near large values with few bits set
@ 2020-03-30 5:34 npiggin at gmail dot com
2020-04-30 17:23 ` [Bug target/94395] " segher at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: npiggin at gmail dot com @ 2020-03-30 5:34 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94395
Bug ID: 94395
Summary: Powerpc suboptimal 64-bit constant generation near
large values with few bits set
Product: gcc
Version: 9.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: npiggin at gmail dot com
Target Milestone: ---
0xc000000000000000UL is generated with
li 9,-1
rldicr 9,9,0,1
0xbfffffffffffffffUL (0xc000000000000000UL - 1) is
lis 9,0xbfff
ori 9,9,0xffff
sldi 9,9,32
oris 9,9,0xffff
ori 9,9,0xffff
Could be
li 9,-1
rldicr 9,9,0,1
subi 9,9,1
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/94395] Powerpc suboptimal 64-bit constant generation near large values with few bits set
2020-03-30 5:34 [Bug target/94395] New: Powerpc suboptimal 64-bit constant generation near large values with few bits set npiggin at gmail dot com
@ 2020-04-30 17:23 ` segher at gcc dot gnu.org
2022-02-11 13:50 ` christophe.leroy at csgroup dot eu
2023-10-08 3:12 ` guojiufu at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: segher at gcc dot gnu.org @ 2020-04-30 17:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94395
Segher Boessenkool <segher at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2020-04-30
Ever confirmed|0 |1
CC| |segher at gcc dot gnu.org
Status|UNCONFIRMED |NEW
--- Comment #1 from Segher Boessenkool <segher at gcc dot gnu.org> ---
li 9,-2 ; rotldi 9,9,62 or similar, even.
Confirmed.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/94395] Powerpc suboptimal 64-bit constant generation near large values with few bits set
2020-03-30 5:34 [Bug target/94395] New: Powerpc suboptimal 64-bit constant generation near large values with few bits set npiggin at gmail dot com
2020-04-30 17:23 ` [Bug target/94395] " segher at gcc dot gnu.org
@ 2022-02-11 13:50 ` christophe.leroy at csgroup dot eu
2023-10-08 3:12 ` guojiufu at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: christophe.leroy at csgroup dot eu @ 2022-02-11 13:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94395
Christophe Leroy <christophe.leroy at csgroup dot eu> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |christophe.leroy at csgroup dot eu
--- Comment #2 from Christophe Leroy <christophe.leroy at csgroup dot eu> ---
Problem still present with GCC 11.2
Linux kernel has a huge amount of sequences like:
b4: 3d 20 fc ff lis r9,-769
b8: 61 29 ff ff ori r9,r9,65535
bc: 79 29 07 c6 rldicr r9,r9,32,31
c0: 65 29 ff ff oris r9,r9,65535
c4: 61 29 ff ff ori r9,r9,65535
c8: 7d 3d 03 a6 mtamr r9
Could instead be:
li r9, -769
rotldi r9, r9, 48
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/94395] Powerpc suboptimal 64-bit constant generation near large values with few bits set
2020-03-30 5:34 [Bug target/94395] New: Powerpc suboptimal 64-bit constant generation near large values with few bits set npiggin at gmail dot com
2020-04-30 17:23 ` [Bug target/94395] " segher at gcc dot gnu.org
2022-02-11 13:50 ` christophe.leroy at csgroup dot eu
@ 2023-10-08 3:12 ` guojiufu at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: guojiufu at gcc dot gnu.org @ 2023-10-08 3:12 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94395
Jiu Fu Guo <guojiufu at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|NEW |RESOLVED
CC| |guojiufu at gcc dot gnu.org
--- Comment #3 from Jiu Fu Guo <guojiufu at gcc dot gnu.org> ---
After r14-4470, the trunk could generate a better code for this case.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-10-08 3:12 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-03-30 5:34 [Bug target/94395] New: Powerpc suboptimal 64-bit constant generation near large values with few bits set npiggin at gmail dot com
2020-04-30 17:23 ` [Bug target/94395] " segher at gcc dot gnu.org
2022-02-11 13:50 ` christophe.leroy at csgroup dot eu
2023-10-08 3:12 ` guojiufu at gcc dot gnu.org
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