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Lexicon Entry

Register Allocation

The compiler phase that maps an unlimited number of virtual registers to the finite set of physical CPU registers.

Related Knowledge & Cross-References

Guide
Apr 9, 2026

Register Allocation in Compilers: How Variables Fit into CPU Registers

Discover how compilers solve register allocation — mapping thousands of virtual registers to 16 (x86-64) or 31 (ARM64) physical ones. See graph coloring, spilling, and rematerialization with real Godbolt examples.

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