Compilers: Principles, Techniques, and Tools, Updated 2nd Edition by Pearson

CHAPTER 9

Machine-Independent Optimizations

High-level language constructs can introduce substantial run-time overhead if we naively translate each construct independently into machine code. This chapter discusses how to eliminate many of these inefficiencies. Elimination of unnecessary instructions in object code, or the replacement of one sequence of instructions by a faster sequence of instructions that does the same thing is usually called “code improvement” or “code optimization.”

Local code optimization (code improvement within a basic block) was introduced in Section 8.5. This chapter deals with global code optimization, where improvements take into account what happens across basic blocks. We begin in Section 9.1 with a discussion of ...