More complete hashcons : lists (dirpath), arrays (constr)

Earlier, the elements of constr arrays were hash-consed, but not the
array itself. This helps a bit when the same (f a1 ... an) is manipulated
a lot : -20% in the size of opaque terms in Integral_domain.vo and Nsatz.vo

Similarly it's interesting to hash-cons sub-lists for dirpaths,
since in Coq.A.B and Coq.A.C we could share Coq.A.

With this patch, the hash-consing of constr seems quasi-optimal:
Pierre-Marie's marshal compactor is unable to shrink opaque tables by
more than 2%, and this difference seems to be due to untyped compaction
(for the compactor Rel 1 = Prop Pos).

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16723 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 5 insertions, 6 deletions

diff --git a/kernel/sorts.ml b/kernel/sorts.ml
index 7ab6b553a..88c99683e 100644
--- a/kernel/sorts.ml
+++ b/kernel/sorts.ml
@@ -51,13 +51,12 @@ module Hsorts =
       type t = _t
       type u = universe -> universe
       let hashcons huniv = function
-          Prop c -> Prop c
         | Type u -> Type (huniv u)
-      let equal s1 s2 =
-        match (s1,s2) with
-            (Prop c1, Prop c2) -> c1 == c2
-          | (Type u1, Type u2) -> u1 == u2
-          |_ -> false
+        | s -> s
+      let equal s1 s2 = match (s1,s2) with
+        | (Prop c1, Prop c2) -> c1 == c2
+        | (Type u1, Type u2) -> u1 == u2
+        |_ -> false
       let hash = Hashtbl.hash
     end)