Does Rust have an equivalent of -Ofast -march=native? [duplicate]

Question

Does Rust have an equivalent of GCC's C CFLAGS="-Ofast -march=native" compiler optimizations?

Answer 1

To optimise for the native CPU, you can use

RUSTFLAGS="-C target-cpu=native"

I think LLVM optimises for speed (or more specifically, throughput) by default; I couldn't really find documentation on this, but this is what the source code suggests.

You should be able to select a different cost model using e.g.

RUSTFLAGS="-C target-cpu=native -C llvm-args='-cost-kind=latency'"

but I haven't tried this, nor do I know any details about the effect of this switch.