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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/61837] missed loop invariant expression optimization
Date: Fri, 15 May 2020 03:27:11 +0000 [thread overview]
Message-ID: <bug-61837-4-Yx2F4Wd44K@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-61837-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61837
--- Comment #11 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Xiong Hu Luo <luoxhu@gcc.gnu.org>:
https://gcc.gnu.org/g:8a15faa730f99100f6f3ed12663563356ec5a2c0
commit r11-407-g8a15faa730f99100f6f3ed12663563356ec5a2c0
Author: Xionghu Luo <luoxhu@linux.ibm.com>
Date: Thu May 14 21:03:24 2020 -0500
Fold (add -1; zero_ext; add +1) operations to zero_ext when not
overflow(PR37451, PR61837)
This "subtract/extend/add" existed for a long time and still annoying us
(PR37451, part of PR61837) when converting from 32bits to 64bits, as the
ctr
register is used as 64bits on powerpc64, Andraw Pinski had a patch but
caused some issue and reverted by Joseph S. Myers(PR37451, PR37782).
Andraw:
http://gcc.gnu.org/ml/gcc-patches/2008-09/msg01070.html
http://gcc.gnu.org/ml/gcc-patches/2008-10/msg01321.html
Joseph:
https://gcc.gnu.org/legacy-ml/gcc-patches/2011-11/msg02405.html
We still can do the simplification from "subtract/zero_ext/add" to
"zero_ext"
when loop iterations is known to be LT than MODE_MAX (only do simplify
when counter+0x1 NOT overflow).
Bootstrap and regression tested pass on Power8-LE.
gcc/ChangeLog
2020-05-15 Xiong Hu Luo <luoxhu@linux.ibm.com>
PR rtl-optimization/37451, part of PR target/61837
* loop-doloop.c (doloop_simplify_count): New function. Simplify
(add -1; zero_ext; add +1) to zero_ext when not wrapping.
(doloop_modify): Call doloop_simplify_count.
gcc/testsuite/ChangeLog
2020-05-15 Xiong Hu Luo <luoxhu@linux.ibm.com>
PR rtl-optimization/37451, part of PR target/61837
* gcc.target/powerpc/doloop-2.c: New test.
next prev parent reply other threads:[~2020-05-15 3:27 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-61837-4@http.gcc.gnu.org/bugzilla/>
2020-04-07 7:30 ` luoxhu at gcc dot gnu.org
2020-04-07 16:37 ` segher at gcc dot gnu.org
2020-04-13 10:31 ` luoxhu at gcc dot gnu.org
2020-04-14 6:42 ` segher at gcc dot gnu.org
2020-04-14 7:01 ` luoxhu at gcc dot gnu.org
2020-04-14 7:26 ` segher at gcc dot gnu.org
2020-04-14 7:52 ` luoxhu at gcc dot gnu.org
2020-04-14 10:37 ` rguenth at gcc dot gnu.org
2020-05-15 3:27 ` cvs-commit at gcc dot gnu.org [this message]
2021-07-29 0:43 ` cvs-commit at gcc dot gnu.org
2021-08-12 2:17 ` guojiufu at gcc dot gnu.org
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