[micro_cam]

There are llvm (and gcc) implementations of go but main/reference implementation was written from scratch in C and later moved to pure go. IIRC the authors wanted to achieve really fast compilation and a few other things that required them to start from scratch.

[nathany]

There was also the matter of figuring out llvm in order to use it. The initial Go compiler was based on the Plan 9 C compiler toolchain, which the designers of Go know well.

One of the other reasons relates to how stacks are handled for goroutines.