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+(**************************************************************************)
+(*                                                                        *)
+(*                                 OCaml                                  *)
+(*                                                                        *)
+(*                       Pierre Chambart, OCamlPro                        *)
+(*           Mark Shinwell and Leo White, Jane Street Europe              *)
+(*                                                                        *)
+(*   Copyright 2013--2016 OCamlPro SAS                                    *)
+(*   Copyright 2014--2016 Jane Street Group LLC                           *)
+(*                                                                        *)
+(*   All rights reserved.  This file is distributed under the terms of    *)
+(*   the GNU Lesser General Public License version 2.1, with the          *)
+(*   special exception on linking described in the file LICENSE.          *)
+(*                                                                        *)
+(**************************************************************************)
+
+[@@@ocaml.warning "+a-4-9-30-40-41-42"]
+
+(** Description of the semantics of primitives, to be used for optimization
+    purposes.
+
+    "No effects" means that the primitive does not change the observable state
+    of the world.  For example, it must not write to any mutable storage,
+    call arbitrary external functions or change control flow (e.g. by raising
+    an exception).  Note that allocation is not "No effects" (see below).
+
+    It is assumed in the compiler that applications of primitives with no
+    effects, whose results are not used, may be eliminated.  It is further
+    assumed that applications of primitives with no effects may be
+    duplicated (and thus possibly executed more than once).
+
+    (Exceptions arising from allocation points, for example "out of memory" or
+    exceptions propagated from finalizers or signal handlers, are treated as
+    "effects out of the ether" and thus ignored for our determination here
+    of effectfulness.  The same goes for floating point operations that may
+    cause hardware traps on some platforms.)
+
+    "Only generative effects" means that a primitive does not change the
+    observable state of the world save for possibly affecting the state of
+    the garbage collector by performing an allocation.  Applications of
+    primitives that only have generative effects and whose results are unused
+    may be eliminated by the compiler.  However, unlike "No effects"
+    primitives, such applications will never be eligible for duplication.
+
+    "Arbitrary effects" covers all other primitives.
+
+    "No coeffects" means that the primitive does not observe the effects (in
+    the sense described above) of other expressions.  For example, it must not
+    read from any mutable storage or call arbitrary external functions.
+
+    It is assumed in the compiler that, subject to data dependencies,
+    expressions with neither effects nor coeffects may be reordered with
+    respect to other expressions.
+*)
+
+type effects = No_effects | Only_generative_effects | Arbitrary_effects
+type coeffects = No_coeffects | Has_coeffects
+
+(** Describe the semantics of a primitive.  This does not take into account of
+    the (non-)(co)effectfulness of the arguments in a primitive application.
+    To determine whether such an application is (co)effectful, the arguments
+    must also be analysed. *)
+val for_primitive: Clambda_primitives.primitive -> effects * coeffects
+
+type return_type =
+  | Float
+  | Other
+
+val return_type_of_primitive: Clambda_primitives.primitive -> return_type