[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.