https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81741
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |jakub at gcc dot gnu.org,
| |law at gcc dot gnu.org
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I see the same behavior with 4.9, as well as older (e.g. 4.8 or 4.4).
The thing is that __builtin_constant_p is (at -O1 and above) a check whether
some expression is constant after optimizations, and here FRE or DOM passes
figure out (due to jump threading?) that it is constant.
Abusing __builtin_constant_p this way is always going to be risky.
