CCC vs GCC

Sun, 08 Feb 2026 00:00:00 +0000

Introduction

Anthropic recently published a blog post about building a C compiler entirely with Claude . They called it CCC (Claude’s C Compiler) and claimed it could compile the Linux kernel. 100% of the code was written by Claude Opus 4.6, a human only guided the process by writing test cases. That sounded interesting enough to test the claim and benchmark CCC against the industry standard GCC.

The source code of CCC is available at claudes-c-compiler . It is written entirely in Rust, targeting x86-64, i686, AArch64 and RISC-V 64. The frontend, SSA-based IR, optimizer, code generator, peephole optimizers, assembler, linker and DWARF debug info generation are all implemented from scratch with zero compiler-specific dependencies. That is a lot of work for an AI to do.

Kernel on Harshanu

CCC vs GCC

Introduction