// returns true if this instruction looks like it moves an ABI
	// register (or context register for rangefunc bodies) to the
	// stack, along with the value being stored.
	isRegMoveLike := func(v *Value) (bool, ID) {
		n, ok := v.Aux.(*ir.Name)
		var r ID
		if (!ok || n.Class != ir.PPARAM) && !needCloCtx {
			return false, r
		}
		regInputs, memInputs, spInputs := 0, 0, 0