1. First do the register mapping and then any possible instruction reordering. How many machine registers are used? Has there been any pipeline improvement?

2. Starting with the original program, now do instruction reordering and then any possible mapping. How many machine registers are used? Has there been any pipeline improvement?

the answer Chegg provided is wrong please don't copy that here thank you

17.6 A RISC machine's compiler may do both a mapping of symbolic registers to ac- tual registers and a rearrangement of in- structions for pipeline efficiency. An interest- ing question arises as to the order in which these two operations should be done. Con- sider the following program fragment: LD SR1, A ;load A into symbolic reg- ister 1 LD SR2, B load B into symbolic reg- ister 2 ADD SR3, SR1, SR2 ;add contents of SR1 and SR2 and store in SR3 LD SR4, C LD SR5, D ADD SR6, SR4, SR5