GRAPHICAL VISUALIZATION OF COMPILER OPTIMIZATIONS

xvpodb, a visualization tool developed to support the analysis of optimizations performed by the vpo optimizer, is described. The tool is a graphical optimization viewer that can display the state of the program representation before and after sequences of changes, referred to as transformations, that result in semantically equivalent (and usually improved) code. The information and insight such visualization provides can simplify the debugging of problems with the optimizer. Unique features of xvpodb include reverse viewing (or undoing) of transformations and the ability to stop at breakpoints associated with the generated instructions. The viewer facilitates the retargeting of vpo to a new machine, supports experimentation with new optimizations, and has been used as a teaching aid in compiler classes.