This patch handles the case that the pointer is a BITCAST of GEP to change the data type. Before this patch, the check stops
at the BITCAST (pointer) and the load/store are not actually handled at all.
We also remove an invalid LIT test because we haven't handled the case yet, and check always pass with or without the promotion because
the index is an immediate and the load/store could be easily optimized away in other optimizations.