The global ctor evaluator tries to evalute function calls where the call
function type and function type do not match, by performing bitcasts.
This currently causes a crash when calling a void function with non-void
return type.
I've opted to remove this functionality entirely rather than fixing this
specific case. With opaque pointers, there shouldn't be a legitimate use
case for this anymore, as we don't need to look through pointer type
casts. Doing other bitcasts is very iffy because it ignores ABI
considerations. We should at least leave adjusting the signatures to
make them line up to InstCombine (which also does some iffy things, but
is at least somewhat more constrained).
Fixes https://github.com/llvm/llvm-project/issues/118725.
5013c81b78