Fp_licence (arrayjit.Ir.Low_level.Fp

Module Low_level.Fp_licence

The licences of the rounding-changing algebra over the reals (gh-ocannl-998), one field per licence, each true when that family of rewrites may run:

contract: fusing a floating a * b + c into one FMA (one rounding instead of two);

reassociate: constant reassociation through Add/Mul, re-parenthesized subtraction chains, the multiplication/division interchanges, and unrolling known integer powers into multiplications;

finite_math: the zero identities x + 0 = x, 0 - x = -x and 0 * x = 0, which hold only for finite operands and ignoring the sign of zero.

Integer precisions take every licence but the floating-only arms (the interchanges and contraction): reassociation is exact in wrapping arithmetic, and the index canonicalizer relies on it.

type t = {

contract : Base.bool;
reassociate : Base.bool;
finite_math : Base.bool;

}

include Sexplib0.Sexpable.S with type t := t

val t_of_sexp : Sexplib0__.Sexp.t -> t

val sexp_of_t : t -> Sexplib0__.Sexp.t

include Ppx_compare_lib.Equal.S with type t := t

val equal : t Base__Ppx_compare_lib.equal

include Ppx_compare_lib.Comparable.S with type t := t

val compare : t Base__Ppx_compare_lib.compare

val exact : t

No licence: only exact rewrites.

val all : t

val of_config : Base.unit -> t

The configured licences: the keys fp_contract, fp_reassociate and fp_finite_math.

val fields : t -> (Base.string * Base.bool) Base.list

Each licence under its config key, for reports.