# Register Allocation

> Expert skill for register allocation algorithms including graph coloring, linear scan, and spill code generation

- Skill: `a5c-ai/register-allocation` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add a5c-ai/register-allocation`
- Raw SKILL.md: https://api.skillmd.com/api/skills/a5c-ai/register-allocation/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: a5c-ai (https://skillmd.com/u/a5c-ai)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/a5c-ai/register-allocation

---


# Register Allocation Skill

## Overview

Expert skill for register allocation algorithms including graph coloring, linear scan, and spill code generation.

## Capabilities

- Implement graph coloring register allocation
- Implement linear scan register allocation
- Generate spill code with minimal overhead
- Handle calling convention register constraints
- Implement register coalescing
- Handle pre-colored nodes and fixed registers
- Implement live range splitting
- Design register pressure analysis

## Target Processes

- jit-compiler-development.js
- code-generation-llvm.js
- bytecode-vm-implementation.js

## Dependencies

None (algorithmic skill)

## Usage Guidelines

1. **Algorithm Selection**: Use linear scan for JIT (fast), graph coloring for AOT (optimal)
2. **Live Ranges**: Compute accurate live ranges before allocation
3. **Spill Costs**: Use heuristics to minimize spill costs (loop depth, usage frequency)
4. **Calling Conventions**: Handle caller/callee-saved registers correctly
5. **Coalescing**: Implement aggressive coalescing to reduce moves

## Output Schema

```json
{
  "type": "object",
  "properties": {
    "algorithm": {
      "type": "string",
      "enum": ["graph-coloring", "linear-scan", "second-chance-binpacking"]
    },
    "spillStrategy": { "type": "string" },
    "registerClasses": {
      "type": "array",
      "items": { "type": "string" }
    },
    "generatedFiles": {
      "type": "array",
      "items": { "type": "string" }
    }
  }
}
```