Computers as Components, 2nd Edition

5.5 Program Optimization 247

case,the lowest-cost covering uses the multiply-add instruction to cover both nodes.

If we first tried to cover the bottom node with the multiply instruction, we would

find ourselves blocked from using the multiply-add instruction. Dynamic program-

ming can be used to efficiently find the lowest-cost covering of trees, and heuristics

can extend the technique to DAGs.

5.5.8 Understanding and Using Your Compiler

Clearly, the compiler can vastly transform your program during the creation of

assembly language. But compilers are also substantially different in terms of the

optimizations they perform. Understanding your compiler