This change promotes load instructions which directly read from stored by
replacing them with mov instructions. If the store is wider than the load,
the load will be replaced with a bitfield extract.
For example :
STRWui %W1, %X0, 1 %W0 = LDRHHui %X0, 3
STRWui %W1, %X0, 1 %W0 = UBFMWri %W1, 16, 31