https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120607
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |INVALID
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Why do you think this is incorrect.
Using -fsanitize=undefined I get the following runtime error message:
/app/example.cpp:14:30: runtime error: execution reached an unreachable program
point
Which means the code is actually undefined.
> but under -O2, GCC incorrectly folds the entire test_builtin_unreachable()
> function, leading to an infinite loop at runtime.
Because with bb == 2, the second if statement is always true so it is converted
into:
if (true)
__builtin_unreachable ();
Which means it is always unreachable.
