Code Generation and Backends

Purpose

Overview LLVM (and general compiler) backend code generation: IR legalization, SelectionDAG instruction selection, register allocation, assembly emission, and what adding a new target entails — complementing IR skills and skills/compiler-internals/llvm-passes.

When to Use

• Reading llc output for a specific target
• Understanding why IR type legalizer inserted extra ops
• Evaluating porting compiler to new architecture (high level)
• Debugging wrong code at asm layer (not IR)

Workflow

1. Backend pipeline (LLVM)