[Bug debug/59515] -Og doesn't generate out-of-line copies of inline functions like -O0 does

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59515

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2013-12-19
                 CC|                            |hubicka at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1
           Severity|normal                      |enhancement

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Thanks for the report - I agree that -Og should preserve an OOL copy of inlined
functions.  I'll see what I can do here (with C++ and a lot of abstraction
penalty the code size impact of that could be quite big though, and via that
also the compile-time increase).  We definitely need to avoid inlining into the
unused offline copy - but usually that's too late because we inline from the
leafs - if we don't the code-size impact is exponential ... :/

Honza, is there a way to do this in a clean way?  That is, create a clone
of all initially reachable functions that we don't inline into, but remove
the clone if the original function prevails?  That is, for

inline int bar () { return 42; }
inline int foo () { return bar() + bar(); }
int main()
{
  return foo ();
}

have main return 84 but offline copies of bar and foo while foo should still
call bar twice?

Not sure if the exponential size consideration matters for -Og which
inlines for size improvements only.