[Bug gcov-profile/114851] New: Alternative to -Wmisexpect from LLVM in GCC

[Bug gcov-profile/114851] New: Alternative to -Wmisexpect from LLVM in GCC

[zamazan4ik at tut dot by]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114851

            Bug ID: 114851
           Summary: Alternative to -Wmisexpect from LLVM in GCC
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: gcov-profile
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zamazan4ik at tut dot by
  Target Milestone: ---

LLVM infrastructure supports a diagnostic for checking mismatches between
user-provided __builtin_expect/[[likely]] hints and PGO profiles:
https://clang.llvm.org/docs/DiagnosticsReference.html#wmisexpect +
https://llvm.org/docs/MisExpect.html (and an example of its usage in Chromium:
https://issues.chromium.org/issues/40694104).

I was trying to find a similar diagnostic in GCC but found nothing. Is there
anything similar in GCC? If not, can we make the issue a Feature Request for
such a feature? Having such a diagnostic can be helpful in practice since it
allows for finding wrongfully placed user hints in sources.

[Bug gcov-profile/114851] Alternative to -Wmisexpect from LLVM in GCC

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114851

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |87403
           Severity|normal                      |enhancement

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I don't think GCC has a warning (yet).


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87403
[Bug 87403] [Meta-bug] Issues that suggest a new warning

[Bug gcov-profile/114851] Alternative to -Wmisexpect from LLVM in GCC

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114851

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #1)
> I don't think GCC has a warning (yet).

Though I do wonder if the "hints" are used instead of the PGO here.

[Bug gcov-profile/114851] Alternative to -Wmisexpect from LLVM in GCC

[zamazan4ik at tut dot by]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114851

--- Comment #3 from Alexander Zaitsev <zamazan4ik at tut dot by> ---
> Though I do wonder if the "hints" are used instead of the PGO here.

We already discussed this question a bit in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112806 . If I understand
correctly, no clear answer yet:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112806#c4 .