[Bug c/93087] New: Bogus `-Wsuggest-attribute=cold` on function already marked as `__attribute__((cold))`

[sagebar at web dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93087

            Bug ID: 93087
           Summary: Bogus `-Wsuggest-attribute=cold` on function already
                    marked as `__attribute__((cold))`
           Product: gcc
           Version: 9.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sagebar at web dot de
  Target Milestone: ---

Created attachment 47555
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47555&action=edit
Issue demonstration

Like the title implies, `-Wsuggest-attribute=cold` is emit for functions that
were already given the `__attribute__((cold))` annotation
The attached file demonstrates the issue, and should be compiled as:
```
gcc -c -O* attached-file.c
```
Where `*` can be any one of `` (empty), `1-3` (though not `0`), `g`, `s`,
`fast`
Note that the issue doesn't arise when no `-O*` flag is given at all (or when
`-O0` is given)