[Bug ipa/99309] [10/11 Regression] Segmentation fault with __builtin_constant_p usage at -O2

["hubicka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99309

Jan Hubicka <hubicka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |hubicka at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #9 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Have WIP patch to attach predicates to buildtin_constant_p and redirect to true
if inliner works out that it is a constat (still relying on late passes to
optimize the if branch well).

>From all the options I can think of this seems best even though it may end up
in relatively rare cases that we do the (very simple) propagation at IPA time
and late optimizations won't.  Without explicitly disabling passes (where I
think this is fine to happen) all testcases we seen so far was of the form that
constant was eventually propagated but only after we folded builtin_constant_p
to false.

Overall it is not possible to assure that builtin_constant_p on memory will
fold to true only if all uses of the memory later in the if branch will ford to
constant since AO has walking limits.