Module `Flambda2_simplify.Specialization_cost`

ontinuation Specialization Cost

Continuation specialization is done in simplify on the way down. Consider a term of the form:

* let_cont k x = * let_cont k' y = * ... * in * .. * switch x with * | 0 -> k' 0 * | 1 -> k' 1 * in * .. * switch .. with * | 0 -> k 0 * | 1 -> k 1

The decision to specialize continuation k is made once Simplify has reached the bottom of the handler of k. This allows to know all of the relevant information before deciding whether to specialize k: all uses of k have been seen, and we have also seen the code for the handler of ĸ.

The type t represents an accumulator updated while doing the downwards pass on the handler of k to record enough information to estimate the cost of a specialization of k, and whether there was any reason to **not** specialize k regardless of the cost

type reason =

| At_toplevel
| Contains_static_consts
| Contains_set_of_closures

type cost = {

size_of_primitives : int;

}

type t = private

| Can_specialize of Flambda2_simplify.Specialization_cost.cost
| Cannot_specialize of {
1. reason : Flambda2_simplify.Specialization_cost.reason;
}

The current specialization status, stored in the dacc.

val print : 
  Stdlib.Format.formatter ->
  Flambda2_simplify.Specialization_cost.t ->
  unit

Printing function.

Creation

val can_specialize : Flambda2_simplify.Specialization_cost.t

Create a Can_specialize value with zero intial cost.

val cannot_specialize : 
  Flambda2_simplify.Specialization_cost.reason ->
  Flambda2_simplify.Specialization_cost.t

Create a value preventing any specialization of the current continuation.

Updating Costs

val add_prim : 
  machine_width:Target_system.Machine_width.t ->
  Flambda2_terms.Flambda_primitive.t ->
  Flambda2_simplify.Specialization_cost.t ->
  Flambda2_simplify.Specialization_cost.t

Add a primitive of the given size to the cost of specialization

val add_set_of_closures : 
  Flambda2_terms.Set_of_closures.t ->
  Flambda2_simplify.Specialization_cost.t ->
  Flambda2_simplify.Specialization_cost.t

Add a set of closure containing ~num closures to the cost of specialization.

val add_lifted_set_of_closures : 
  Flambda2_terms.Set_of_closures.t ->
  Flambda2_simplify.Specialization_cost.t ->
  Flambda2_simplify.Specialization_cost.t

Module Flambda2_simplify.Specialization_cost

Creation

Updating Costs

Module `Flambda2_simplify.Specialization_cost`