move OP_LOADNIL just before OP_SEND to improve performance on some platforms

src/vm.c

@@ -481,14 +481,6 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
       NEXT;
     }
 
-    CASE(OP_LOADNIL) {
-      /* A B    R(A) := nil */
-      int a = GETARG_A(i);
-
-      SET_NIL_VALUE(regs[a]);
-      NEXT;
-    }
-
     CASE(OP_LOADSELF) {
       /* A      R(A) := self */
       regs[GETARG_A(i)] = mrb->stack[0];
@@ -680,6 +672,14 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
       NEXT;
     }
 
+    CASE(OP_LOADNIL) {
+      /* A B    R(A) := nil */
+      int a = GETARG_A(i);
+
+      SET_NIL_VALUE(regs[a]);
+      NEXT;
+    }
+
   L_SEND:
     CASE(OP_SEND) {
       /* A B C  R(A) := call(R(A),Sym(B),R(A+1),... ,R(A+C-1)) */