Not my area of expertise, so I want to ask this question: Do compiler optimizations exist to automatically parallelize a for loop, which can be parallelized, no

Not my area of expertise, so I want to ask this question: Do compiler optimizations exist to automatically parallelize a for loop, which can be parallelized, no matter how to programmer wrote their for loop? If not, then map / reduce offers non-trivial performance benefits over a for loop. Mapping, as far as I'm aware, is "embarrassingly parallel", assuming the function that's mapped is pure? I think?