Most compiler optimizations are applied only within a function. The compiler analyzes a function's flow of execution and how the function uses variables. It uses this information to find shortcuts in execution and reduce the number of registers and memory that the function uses. These optimizations are useful and effective but are limited to the scope of a function.
The CodeWarrior compiler has a special optimization that it applies at a greater scope. Widening the scope of an optimization offers the potential to greatly improve performance and reduce memory use. Interprocedural analysis examines the flow of execution and data within entire files.