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From: "cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/103743] PPC: Inefficient equality compare for large 64-bit constants having only 16-bit relevant bits in high part
Date: Tue, 20 Dec 2022 03:59:43 +0000 [thread overview]
Message-ID: <bug-103743-4-u3Hf6ugi9z@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-103743-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103743
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jiu Fu Guo <guojiufu@gcc.gnu.org>:
https://gcc.gnu.org/g:1060cd2ad00b5174f4f8ef8ca3d8c283e321ffca
commit r13-4803-g1060cd2ad00b5174f4f8ef8ca3d8c283e321ffca
Author: Jiufu Guo <guojiufu@linux.ibm.com>
Date: Tue Dec 20 11:43:57 2022 +0800
rs6000: Optimize cmp on rotated 16bits constant
Hi,
When checking eq/ne with a constant which has only 16bits, it can be
optimized to check the rotated data. By this, the constant building
is optimized.
As the example in PR103743:
For "in == 0x8000000000000000LL", this patch generates:
rotldi 3,3,1 ; cmpldi 0,3,1
instead of:
li 9,-1 ; rldicr 9,9,0,0 ; cmpd 0,3,9
Compare with previous version:
https://gcc.gnu.org/pipermail/gcc-patches/2022-August/600475.html.
This patch refactor the code according to review comments.
e.g. updating function names/comments/code.
This patch pass bootstrap and regtest on ppc64 and ppc64le.
Is it ok for trunk? Thanks for comments!
BR,
Jeff(Jiufu)
PR target/103743
gcc/ChangeLog:
* config/rs6000/rs6000-protos.h (can_be_rotated_to_lowbits): New.
(can_be_rotated_to_positive_16bits): New.
(can_be_rotated_to_negative_15bits): New.
* config/rs6000/rs6000.cc (can_be_rotated_to_lowbits): New
definition.
(can_be_rotated_to_positive_16bits): New definition.
(can_be_rotated_to_negative_15bits): New definition.
* config/rs6000/rs6000.md (*rotate_on_cmpdi): New
define_insn_and_split.
(eqne): Move earlier.
gcc/testsuite/ChangeLog:
* gcc.target/powerpc/pr103743.c: New test.
* gcc.target/powerpc/pr103743_1.c: New test.
next prev parent reply other threads:[~2022-12-20 3:59 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-16 6:46 [Bug target/103743] New: " jens.seifert at de dot ibm.com
2021-12-16 6:49 ` [Bug target/103743] " pinskia at gcc dot gnu.org
2021-12-16 15:06 ` bergner at gcc dot gnu.org
2021-12-16 22:14 ` pthaugen at gcc dot gnu.org
2022-03-15 2:06 ` guojiufu at gcc dot gnu.org
2022-03-15 7:32 ` guojiufu at gcc dot gnu.org
2022-03-16 9:48 ` guojiufu at gcc dot gnu.org
2022-05-16 1:59 ` guojiufu at gcc dot gnu.org
2022-12-20 3:59 ` cvs-commit at gcc dot gnu.org [this message]
2023-01-09 5:29 ` guojiufu at gcc dot gnu.org
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