Using CPU Registers
Register allocation maps the large number of temporary variables in IR to the limited number of CPU registers. Variables that don't fit go to memory (spilling).
The Problem
Graph Coloring Approach
R):
Spill some variables to memory
Example:
t1 interferes with t2 → different registers
t1 interferes with t3 → different registers
t2 and t3 don't interfere → can share register