builtin-ref takes immediate parameter

* module/language/cps/compile-bytecode.scm (compile-function):
* module/language/cps/reify-primitives.scm (builtin-ref):
* module/language/cps/slot-allocation.scm (compute-needs-slot):
  Builtin-ref uses immediate parameter.

module/language/cps/compile-bytecode.scm

@@ -201,8 +201,8 @@
         (($ $primcall 'ulsh/immediate #f (x y))
          (emit-ulsh/immediate asm (from-sp dst) (from-sp (slot x))
                               (constant y)))
-        (($ $primcall 'builtin-ref #f (name))
-         (emit-builtin-ref asm (from-sp dst) (constant name)))
+        (($ $primcall 'builtin-ref idx ())
+         (emit-builtin-ref asm (from-sp dst) idx))
         (($ $primcall 'scm->f64 #f (src))
          (emit-scm->f64 asm (from-sp dst) (from-sp (slot src))))
         (($ $primcall 'load-f64 val ())

module/language/cps/reify-primitives.scm

@@ -95,9 +95,8 @@
 
 (define (builtin-ref cps idx k src)
   (with-cps cps
-    ($ (with-cps-constants ((idx idx))
-         (build-term
-           ($continue k src ($primcall 'builtin-ref #f (idx))))))))
+    (build-term
+      ($continue k src ($primcall 'builtin-ref idx ())))))
 
 (define (reify-clause cps ktail)
   (with-cps cps

module/language/cps/slot-allocation.scm

@@ -340,8 +340,6 @@ the definitions that are live before and after LABEL, as intsets."
                                'ursh/immediate 'ulsh/immediate) #f
                  (x y))
               (defs+ x))
-             (($ $primcall 'builtin-ref #f (idx))
-              defs)
              (_
               (defs+* (get-uses label))))))
         (($ $kreceive arity k)