Clean unused values from pattern matching

Try to lighten the CPS transformation, using fewer continuations when
there is no need for one

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "src/tests_shared"]
+	path = src/tests_shared
+	url = git@github.com:tobast/mpri18-funcprog-tests.git

src/CPS.ml

@@ -35,16 +35,8 @@ let rec has_calls (t: S.term): bool = match t with
         (* A lambda itself may contain calls, but this call is not evaluated at
          * declaration time *)
 | S.App _ -> true
-| S.IfZero (cond, tIf, tElse) ->
-        (* Cannot optimize continuation creation
-        List.exists has_calls [cond; tIf; tElse]
-        *)
-        true
-| S.Print value ->
-        (* Cannot optimize continuation creation
-        has_calls value
-        *)
-        true
+| S.IfZero _ -> true (* Cannot optimize that with the current languages *)
+| S.Print _ -> true (* Cannot optimize that with the current languages *)
 | S.Let (_, value, next) ->
         List.exists has_calls [value; next]
 
@@ -61,7 +53,16 @@ let rec cps_term_inner (t: S.term) (cont: T.variable) (nameHint: string option)
 : T.term = match t with
 | S.Var _ -> cps_value_as_term t cont
 | S.Lit _ -> cps_value_as_term t cont
-| S.BinOp _ -> cps_value_as_term t cont
+| S.BinOp (t1, op, t2) ->
+        (try cps_value_as_term t cont
+        with NotValue _ -> (
+            let t1Var = freshVar ()
+            and t2Var = freshVar () in
+            light_term t1Var t1 None @@
+                light_term t2Var t2 None @@
+                    T.TailCall(T.vvar cont,
+                        [T.VBinOp(T.vvar t1Var, op, T.vvar t2Var)])
+        ))
 | S.Lam _ as lambda ->
         let fName = freshBlockVarHinted nameHint in
         light_term fName lambda None @@

src/tests/if_fib.exp

@@ -0,0 +1 @@
+../tests_shared/if_fib.exp

src/tests/if_fib.lambda

@@ -0,0 +1 @@
+../tests_shared/if_fib.lambda

src/tests/if_nested.exp

@@ -0,0 +1 @@
+../tests_shared/if_nested.exp

src/tests/if_nested.lambda

@@ -0,0 +1 @@
+../tests_shared/if_nested.lambda

src/tests/multi_args.lambda

@@ -1,2 +1,2 @@
 let sum = fun x -> fun y -> x + y in
-print(40 + 2)
+print(sum 40 2)

src/tests/ren.exp

@@ -0,0 +1 @@
+../tests_shared/ren.exp

src/tests/ren.lambda

@@ -0,0 +1 @@
+../tests_shared/ren.lambda

src/tests_shared

@@ -0,0 +1 @@
+Subproject commit ab7549347e5b6b51183c5704048c6768aab23d86