Specializing hash functions for widely used types.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16933 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 5 insertions, 1 deletions

diff --git a/kernel/closure.ml b/kernel/closure.ml
index a32be4f69..98fb467c8 100644
--- a/kernel/closure.ml
+++ b/kernel/closure.ml
@@ -213,7 +213,11 @@ module IdKeyHash =
 struct
   type t = id_key
   let equal = Names.eq_id_key
-  let hash = Hashtbl.hash
+  open Hashset.Combine
+  let hash = function
+  | ConstKey c -> combinesmall 1 (Constant.hash c)
+  | VarKey id -> combinesmall 2 (Id.hash id)
+  | RelKey i -> combinesmall 3 (Int.hash i)
 end
 
 module KeyTable = Hashtbl.Make(IdKeyHash)