In GPUs GLSL like types compile down to what basically is variable length SIMD. A vec4 doesn't get compiled to a SIMD vector with four floats, but rather to fou

In GPUs GLSL like types compile down to what basically is variable length SIMD. A vec4 doesn't get compiled to a SIMD vector with four floats, but rather to four SIMD vectors, each containing N FP32 elements (usually 32 or 64). Look at what this simple shader compiles down to on RGA: https://godbolt.org/z/4GrfY61vf https://godbolt.org/z/4GrfY61vf