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From: Jan Hubicka <hubicka@kam.mff.cuni.cz>
To: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
Cc: gcc-bugs@gcc.gnu.org
Subject: Re: [Bug tree-optimization/103989] [12 regression] std::optional and
 bogus -Wmaybe-unitialized at -Og since r12-1992-g6feb628a706e86eb
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> --- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
> Honza, -Og was supposed to not do so much work, I intended to disable IPA
> inlining but there's no knob for that.  I wonder where to best put such
> guard?  I set flag_inline_small_functions to zero for -Og but we still
> run inline_small_functions ().  Basically -Og was supposed to only do
> early opts and then what is necessary for correct RTL expansion.  Doing
> IPA inlining defeats this :/
> 
> Can you help?  Is it safe to simply gate the inline_small_functions ()
> call?  Do we want an extra -f[no-]ipa-inline like we have -fearly-inlining?
> 
> Using -fdisable-ipa-inline gets rid of the diagnostic

You can not disable an IPA pass becasuse then we will mishandle
optimize attributes.  I think you simply want to set

flag_inline_small_functions = 0
flag_inline_functions_called_once = 0 

and we should only inline always_inlines. inline_small_functions will
still loop and check inlinability of functions but if everything is
compiled with -Og it will not find anything inlinable and exit.

Perhaps we may also extend initialize_inline_failed to add
CIF_DEBUG_OPTIMIZE so -Winline does say something more useufl then
"function not considered"

Honza