Matt Godbolt's blog
15 hours ago
- Compilers often optimize loop code, making seemingly expensive operations fast through techniques like using induction variables.
- Loop optimizations like transforming multiplications into series of additions can sometimes be rejected by the compiler if multiplications are already fast and independent.
- Independent loop iterations allow the CPU to overlap calculations, improving throughput despite longer per-iteration latency.
- Tools like Compiler Explorer and llvm-mca can verify compiler optimizations and analyze CPU performance.
- Trust compilers for optimizations but always verify with benchmarks and analysis tools.