I conducted a benchmark comparing GCC against Claude’s C Compiler (CCC), an AI-generated compiler created by Claude Opus 4.6. Using a non-trivial Turing machine simulator as our test program, I evaluated correctness, execution performance, microarchitectural efficiency, and assembly code quality.

Key Findings:

100% Correctness: CCC produces functionally identical output across all test cases

2.76x Performance Gap: CCC-compiled binaries run slower than GCC -O2 but 12% faster than GCC -O0

3.3x Instruction Overhead: CCC generates significantly more instructions due to limited optimization

Surprisingly High IPC: Despite verbosity, CCC achieves 4.89 instructions per cycle vs GCC’s 4.13