[Bug middle-end/59658] New: Document -f* flags enabled by -Og

[Bug middle-end/59658] New: Document -f* flags enabled by -Og

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59658

            Bug ID: 59658
           Summary: Document -f* flags enabled by -Og
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Keywords: documentation
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: burnus at gcc dot gnu.org

http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-O-775 documents
the -f* flags enabled by -O*. And the -f* options document their respective -O*
options which enables them.

However, for -Og this is not documented. The information can be obtained using:
  gcc -Q --help=optimizers -Og|grep enabled

It might be useful to have this information in the man page for -Og as well.

[Bug middle-end/59658] Document -f* flags enabled by -Og

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59658

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-01-07
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
But it might be misleading (similar to -O0 vs -O2) - enabling for example
-ftree-pre won't enable PRE for -Og as it has a completely different
pass pipeline which is not based on -O[123].  Those enumerations are only
relevant for the 'numbered' optimization levels (excluding -O0).

So we miss to filter options in --help optimizers that can be enabled at all.