In commit a7ee80fab2 a ptr->ptr bitcast was removed. But that
seem to cause "Expected an cast instruction!" assertions later in
that pass. This patch will add back the bitcast again.
This was a bit unexpected since there is no bitcast added after
creating the Add instruction in the else clause, but I guess there
is something special with the GetElementPtr scenario which makes this
bitcast needed to avoid such asserts.
This patch is also adding a reproducer for
https://github.com/llvm/llvm-project/issues/52689
that started to fail due to hitting the above mentioned assert. Now
it should end up hitting the assertion failure from #52689 again.
85eeba48a0