Improve wording of inlining reports (ocaml#1001)

Author: lpw25

middle_end/inlining_decision.ml

@@ -104,7 +104,7 @@ let inline env r ~lhs_of_application
         | T.Never_inline -> assert false
         | T.Can_inline_if_no_larger_than threshold -> threshold
       in
-      Don't_try_it (S.Not_inlined.Function_obviously_too_large threshold)
+      Don't_try_it (S.Not_inlined.Above_threshold threshold)
     else if not (toplevel && branch_depth = 0)
          && A.all_not_useful (E.find_list_exn env args) then
       (* When all of the arguments to the function being inlined are unknown,
@@ -173,7 +173,7 @@ let inline env r ~lhs_of_application
            should already have been simplified (inside its declaration), so
            we also expect no gain from the code below that permits inlining
            inside the body. *)
-        Don't_try_it S.Not_inlined.Unspecialised
+        Don't_try_it S.Not_inlined.No_useful_approximations
     else begin
       (* There are useful approximations, so we should simplify. *)
       Try_it
@@ -374,7 +374,7 @@ let specialise env r ~lhs_of_application
         | T.Never_inline -> assert false
         | T.Can_inline_if_no_larger_than threshold -> threshold
       in
-      Don't_try_it (S.Not_specialised.Function_obviously_too_large threshold)
+      Don't_try_it (S.Not_specialised.Above_threshold threshold)
     else if not (Var_within_closure.Map.is_empty (Lazy.force bound_vars)) then
       Don't_try_it S.Not_specialised.Not_closed
     else if not (Lazy.force recursive) then

middle_end/inlining_stats_types.ml

@@ -73,9 +73,9 @@ end
 module Not_inlined = struct
   type t =
     | Classic_mode
-    | Function_obviously_too_large of int
+    | Above_threshold of int
     | Annotation
-    | Unspecialised
+    | No_useful_approximations
     | Unrolling_depth_exceeded
     | Self_call
     | Without_subfunctions of Wsb.t
@@ -86,19 +86,20 @@ module Not_inlined = struct
     | Classic_mode ->
       Format.pp_print_text ppf
         "This function was prevented from inlining by `-Oclassic'."
-    | Function_obviously_too_large size ->
+    | Above_threshold size ->
       Format.pp_print_text ppf
         "This function was not inlined because \
-         it was obviously too large";
+         it was larger than the current size threshold";
         Format.fprintf ppf "(%i)" size
     | Annotation ->
       Format.pp_print_text ppf
         "This function was not inlined because \
          of an annotation."
-    | Unspecialised ->
+    | No_useful_approximations ->
       Format.pp_print_text ppf
         "This function was not inlined because \
-         its parameters could not be specialised."
+         there was no useful information about any of its parameters, \
+         and it was not particularly small."
     | Unrolling_depth_exceeded ->
       Format.pp_print_text ppf
         "This function was not inlined because \
@@ -118,9 +119,9 @@ module Not_inlined = struct
 
   let calculation ~depth ppf = function
     | Classic_mode
-    | Function_obviously_too_large _
+    | Above_threshold _
     | Annotation
-    | Unspecialised
+    | No_useful_approximations
     | Unrolling_depth_exceeded
     | Self_call -> ()
     | Without_subfunctions wsb ->
@@ -169,7 +170,7 @@ end
 module Not_specialised = struct
   type t =
     | Classic_mode
-    | Function_obviously_too_large of int
+    | Above_threshold of int
     | Annotation
     | Not_recursive
     | Not_closed
@@ -183,10 +184,10 @@ module Not_specialised = struct
       Format.pp_print_text ppf
         "This function was prevented from specialising by \
           `-Oclassic'."
-    | Function_obviously_too_large size ->
+    | Above_threshold size ->
       Format.pp_print_text ppf
         "This function was not specialised because \
-         it was obviously too large";
+         it was larger than the current size threshold";
         Format.fprintf ppf "(%i)" size
     | Annotation ->
       Format.pp_print_text ppf
@@ -220,7 +221,7 @@ module Not_specialised = struct
 
   let calculation ~depth ppf = function
     | Classic_mode
-    | Function_obviously_too_large _
+    | Above_threshold _
     | Annotation
     | Not_recursive
     | Not_closed

middle_end/inlining_stats_types.mli

@@ -32,9 +32,9 @@ end
 module Not_inlined : sig
   type t =
     | Classic_mode
-    | Function_obviously_too_large of int
+    | Above_threshold of int
     | Annotation
-    | Unspecialised
+    | No_useful_approximations
     | Unrolling_depth_exceeded
     | Self_call
     | Without_subfunctions of
@@ -57,7 +57,7 @@ end
 module Not_specialised : sig
   type t =
     | Classic_mode
-    | Function_obviously_too_large of int
+    | Above_threshold of int
     | Annotation
     | Not_recursive
     | Not_closed