Typically compilers have a "frontend" which turns code into a syntax tree and different "backends" for each architecture they need to support. For example, clan

Typically compilers have a "frontend" which turns code into a syntax tree and different "backends" for each architecture they need to support. For example, clang is the C front-end for LLVM while Emscripten is a backend that allows it to output Javascript. Though for highly specialized calculations like that. they're often written into popular libraries like OpenSSL with inline assembly for all relevant architectures.