[Bug middle-end/113907] [14 regression] ICU miscompiled since on x86 since r14-5109-ga291237b628f41

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113907

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

           What    |Removed                     |Added
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                 CC|                            |hubicka at gcc dot gnu.org

--- Comment #29 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Safest fix is to make equals_p to reject merging functions with different value
ranges assigned to corresponding SSA names.  I would hope that, since early
opts are still mostly local, that does not lead to very large degradation. This
is lame of course.

If we go for smarter merging, we need to also handle ipa-prop jump functions. 
In that case I think equals_p needs to check if value range sin SSA_NAMES and
jump functions differs and if so, keep that noted so the merging code can do
corresponding update.  I will check how hard it is to implement this. 
(Equality handling is Martin Liska's code, but if I recall right, each
equivalence class has a leader, and we can keep track if there are some
differences WRT that leader, but I do not recall how subdivision of equivalence
classes is handled).