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From: "guojiufu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/108757] We do not simplify (a - (N*M)) / N + M -> a / N
Date: Fri, 12 May 2023 09:35:05 +0000 [thread overview]
Message-ID: <bug-108757-4-6tIRPtjSke@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108757-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108757
--- Comment #24 from Jiu Fu Guo <guojiufu at gcc dot gnu.org> ---
(In reply to Jiu Fu Guo from comment #23)
> /* Simplify ((t + -N*M) / N + M) -> t / N: (t + -C) >> N + (C>>N) ==> t >> N
> */
> (for div (trunc_div exact_div)
div was not used in this matcher, yet. Here rshift is used: t/(1<<N) could be
optimized to "t>>N".
> (simplify
> (plus (rshift (plus @0 INTEGER_CST@1) INTEGER_CST@2) INTEGER_CST@3)
> (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type) &&
> (wi::to_wide (@3) << wi::to_wide (@2)) == -wi::to_wide (@1))
> (if (TYPE_OVERFLOW_UNDEFINED (type))
> (div @0 @2)
This should be "(rshift @0 @2)", otherwise it will be error if relax
"TYPE_UNSIGNED (type)"
next prev parent reply other threads:[~2023-05-12 9:35 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-10 22:26 [Bug tree-optimization/108757] New: " bergner at gcc dot gnu.org
2023-02-10 22:28 ` [Bug tree-optimization/108757] " bergner at gcc dot gnu.org
2023-02-10 22:33 ` pinskia at gcc dot gnu.org
2023-02-10 22:40 ` pinskia at gcc dot gnu.org
2023-02-11 13:14 ` anlauf at gcc dot gnu.org
2023-02-11 16:38 ` segher at gcc dot gnu.org
2023-02-11 17:32 ` bergner at gcc dot gnu.org
2023-02-11 17:55 ` segher at gcc dot gnu.org
2023-02-11 18:05 ` bergner at gcc dot gnu.org
2023-02-11 18:15 ` segher at gcc dot gnu.org
2023-02-11 19:45 ` chip.kerchner at ibm dot com
2023-02-11 21:55 ` chip.kerchner at ibm dot com
2023-02-11 22:03 ` chip.kerchner at ibm dot com
2023-02-13 20:13 ` chip.kerchner at ibm dot com
2023-02-13 20:20 ` pinskia at gcc dot gnu.org
2023-02-13 20:27 ` [Bug rtl-optimization/108757] " pinskia at gcc dot gnu.org
2023-02-13 20:36 ` chip.kerchner at ibm dot com
2023-02-13 20:37 ` chip.kerchner at ibm dot com
2023-02-13 20:58 ` [Bug tree-optimization/108757] " pinskia at gcc dot gnu.org
2023-02-13 20:59 ` pinskia at gcc dot gnu.org
2023-02-13 21:01 ` pinskia at gcc dot gnu.org
2023-05-11 13:15 ` guojiufu at gcc dot gnu.org
2023-05-11 17:32 ` pinskia at gcc dot gnu.org
2023-05-12 1:52 ` guojiufu at gcc dot gnu.org
2023-05-12 6:25 ` guojiufu at gcc dot gnu.org
2023-05-12 9:35 ` guojiufu at gcc dot gnu.org [this message]
2023-09-04 2:46 ` cvs-commit at gcc dot gnu.org
2023-09-04 3:26 ` guojiufu at gcc dot gnu.org
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