[Bug c/101474] New: -fipa-icf generates worse code for identical function

[vegard.nossum at oracle dot com]

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