https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81596
--- Comment #1 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
Well, it looks like we're purposely not handling the aforementioned case in the
rest of the threader. So perhaps this is more of a feature request.
Jeff, is this worth looking into, or should we close this?
/* We can get a length of 0 here when the statement that
makes a conditional generate a compile-time constant
result is in the same block as the conditional.
That's not really a jump threading opportunity, but instead is
simple cprop & simplification. We could handle it here if we
wanted by wiring up all the incoming edges. If we run this
early in IPA, that might be worth doing. For now we just
reject that case. */
if (path_length == 0)
return NULL;
