Optimal register sharing for high-level synthesis of SSA form programs
Philip Brisk, Foad Dabiri, Roozbeh Jafari, Majid Sarrafzadeh · IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems · 2006
Register sharing for high-level synthesis of programs represented in static single assignment (SSA) form is proven to have a polynomial-time solution. Register sharing is modeled as a graph-coloring problem. Although graph coloring is NP-Complete in the general case, an interference graph constructed for a program in SSA form probably belongs to the class of chordal graphs that have an optimal O(|V|+|E|) time algorithm. Chordal graph coloring reduces the number of registers allocated to the program by as much as 86% and 64.93% on average compared to linear scan register allocation.