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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 tree-optimization/108757] We do not simplify (a - (N*M)) / N + M -> a / N
Date: Mon, 04 Sep 2023 02:46:46 +0000	[thread overview]
Message-ID: <bug-108757-4-Cx0OXY7QDR@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 #25 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:1aceceb1e2d6e86ce183c8cc448750fa03b6f79e

commit r14-3644-g1aceceb1e2d6e86ce183c8cc448750fa03b6f79e
Author: Jiufu Guo <guojiufu@linux.ibm.com>
Date:   Mon Sep 4 10:31:04 2023 +0800

    Optimize '(X - N * M) / N' to 'X / N - M' if valid

    Integer expression "(X - N * M) / N" can be optimized to "X / N - M" with
    the below conditions:
    1. There is no wrap/overflow/underflow.
       wrap/overflow/underflow breaks the arithmetic operation.
    2. "X - N * M" and "X" are not of opposite sign.
       Here, the operation "/" would be "trunc_div", the fractional part is
       discarded. If "X - N * M" and "X" are in different signs, then trunc_div
       discards the fractional parts (of /N) in different directions.

            PR tree-optimization/108757

    gcc/ChangeLog:

            * match.pd ((X - N * M) / N): New pattern.
            ((X + N * M) / N): New pattern.
            ((X + C) div_rshift N): New pattern.

    gcc/testsuite/ChangeLog:

            * gcc.dg/pr108757-1.c: New test.
            * gcc.dg/pr108757-2.c: New test.
            * gcc.dg/pr108757.h: New test.

  parent reply	other threads:[~2023-09-04  2:46 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
2023-09-04  2:46 ` cvs-commit at gcc dot gnu.org [this message]
2023-09-04  3:26 ` guojiufu at gcc dot gnu.org

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