Comparing conservative coalescing criteria

DMCA

Comparing conservative coalescing criteria (2005)

Cached

Download Links

Other Repositories/Bibliography

DBLP

by Max Hailperin , Gustavus Adolphus College

Venue:	ACM Trans. Programming Languages and Systems
Citations:	3 - 0 self

BibTeX

@ARTICLE{Hailperin05comparingconservative,
    author = {Max Hailperin and Gustavus Adolphus College},
    title = {Comparing conservative coalescing criteria},
    journal = {ACM Trans. Programming Languages and Systems},
    year = {2005},
    pages = {571--582}
}

OpenURL

Abstract

Graph-coloring register allocators can eliminate copy instructions from a program by coalescing the interference graph nodes corresponding to the source and destination. Briggs showed that by limiting coalescing to those situations that he dubbed “conservative, ” it could be prevented from causing spilling, i.e., a situation where the allocator fails to assign a register to each live range. George and Appel adopted Briggs’s conservativeness criterion in general, but provided an alternative criterion (the George test) to use in those cases where one of the nodes has been “precolored, ” i.e., pre-assigned a specific register. They motivated this alternative criterion by efficiency considerations, and provided no indication of the relative power of the two criteria. Thus it remained an open question whether the efficiency had been bought at the expense of reduced coalescing. Their implementation also used a limited version of the Briggs test, in place of the original, full version, without any comment on the impact of this substitution. In this paper we also present an analogously limited version of the George test. Thus we are now confronted with four different criteria for conservative coalescing: the full and limited Briggs tests and the full and limited George tests. We present a number of theorems characterizing the relative power of these different criteria, and a number of theorems characterizing

Keyphrases

conservative coalescing criterion limited version relative power george test different criterion alternative criterion reduced coalescing graph-coloring register allocator limited george test full version briggs conservativeness criterion briggs test specific register live range efficiency consideration interference graph node open question limited briggs test copy instruction conservative coalescing

DMCA