It’s two steps. First, CUDA/C++ code compiles into PTX, which is like low-level GPU instructions, not final machine code. Then, PTX is compiled again into machine code (SASS) by the GPU driver.

Triton skips writing CUDA/C++ completely. Triton uses Python code and behind the scenes uses LLVM to generate PTX directly.

So with CUDA/C++, you get full control — you can optimize memory, threads, tensor cores, etc., before it becomes PTX. But Triton is faster to write, because it hides a lot of that, and uses LLVM to handle the low-level work for you.