As with all the ahead-of-time compiled languages that I checked, the answer is that it generates non-SIMD code for the hot loop. The assembly code I see in godb

As with all the ahead-of-time compiled languages that I checked, the answer is that it generates non-SIMD code for the hot loop. The assembly code I see in godbolt.org isn't bad at all; the compiler just didn't do anything super clever.