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From: "vegard.nossum at oracle dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/101474] New: -fipa-icf generates worse code for identical function
Date: Fri, 16 Jul 2021 16:33:54 +0000	[thread overview]
Message-ID: <bug-101474-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101474

            Bug ID: 101474
           Summary: -fipa-icf generates worse code for identical function
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vegard.nossum at oracle dot com
  Target Milestone: ---

Created attachment 51166
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51166&action=edit
Test case

I've come across a weird behaviour when using -fipa-icf, could maybe be related
to bug 80277.

Build with -O1 -fipa-icf and the second version of the identical function
actually has worse codegen than if you have just one of them there or than if
you hadn't passed -fipa-icf at all.

See example: https://godbolt.org/z/n8zz947aK

             reply	other threads:[~2021-07-16 16:33 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-16 16:33 vegard.nossum at oracle dot com [this message]
2021-07-16 16:42 ` [Bug tree-optimization/101474] SRA sometimes produces worse code with inline functions (seen with -fipa-icf sometimes) pinskia at gcc dot gnu.org
2021-07-19  6:21 ` rguenth at gcc dot gnu.org
2021-11-22  6:42 ` pinskia at gcc dot gnu.org
2021-11-22  7:03 ` pinskia at gcc dot gnu.org

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