Function recognize_reduction 

pub fn recognize_reduction(
    stmts: &[Stmt<'_>],
    _interner: &Interner,
) -> Result<ReductionSpec, ReductionReject>

Recognize the rmsnorm / softmax normalize-loop idiom the sugar desugars to — a counted loop that Pushes X[p] / denom (rmsnorm) or e^(X[p]-m) / s (softmax) into Y — anywhere (through Splice).