diff --git a/src/codeobject.h b/src/codeobject.h
index bff4207b..8256f6c4 100644
--- a/src/codeobject.h
+++ b/src/codeobject.h
@@ -86,34 +86,7 @@ struct CodeObject {
     }
 
     void optimize(){
-        for(int i=0; i<codes.size(); i++){
-            if(codes[i].op >= OP_BINARY_OP && codes[i].op <= OP_CONTAINS_OP){
-                for(int j=0; j<2; j++){
-                    Bytecode& bc = codes[i-j-1];
-                    if(bc.op >= OP_LOAD_CONST && bc.op <= OP_LOAD_NAME_REF){
-                        if(bc.op == OP_LOAD_NAME_REF){
-                            bc.op = OP_LOAD_NAME;
-                        }
-                    }else{
-                        break;
-                    }
-                }
-            }else if(codes[i].op == OP_CALL){
-                int ARGC = codes[i].arg & 0xFFFF;
-                int KWARGC = (codes[i].arg >> 16) & 0xFFFF;
-                if(KWARGC != 0) continue;
-                for(int j=0; j<ARGC+1; j++){
-                    Bytecode& bc = codes[i-j-1];
-                    if(bc.op >= OP_LOAD_CONST && bc.op <= OP_LOAD_NAME_REF){
-                        if(bc.op == OP_LOAD_NAME_REF){
-                            bc.op = OP_LOAD_NAME;
-                        }
-                    }else{
-                        break;
-                    }
-                }
-            }
-        }
+        for(int i=0; i<codes.size(); i++){}
     }
 
     /************************************************/
diff --git a/src/compiler.h b/src/compiler.h
index 2740e52b..3db7b1d7 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -597,11 +597,11 @@ __LISTCOMP:
                 const _Str& key = parser->prev.str();
                 emit(OP_LOAD_CONST, co()->add_const(vm->PyStr(key)));
                 consume(TK("="));
-                EXPR();
+                co()->_rvalue=true; EXPR(); co()->_rvalue=false;
                 KWARGC++;
             } else{
                 if(KWARGC > 0) SyntaxError("positional argument follows keyword argument");
-                EXPR();
+                co()->_rvalue=true; EXPR(); co()->_rvalue=false;
                 ARGC++;
             }
             match_newlines(mode()==REPL_MODE);
@@ -758,8 +758,9 @@ __LISTCOMP:
 
     void compile_if_stmt() {
         match_newlines();
-        EXPR_TUPLE();
-
+        co()->_rvalue = true;
+        EXPR_TUPLE();   // condition
+        co()->_rvalue = false;
         int ifpatch = emit(OP_POP_JUMP_IF_FALSE);
         compile_block_body();
 
@@ -780,7 +781,9 @@ __LISTCOMP:
 
     void compile_while_loop() {
         co()->_enter_block(WHILE_LOOP);
-        EXPR_TUPLE();
+        co()->_rvalue = true;
+        EXPR_TUPLE();   // condition
+        co()->_rvalue = false;
         int patch = emit(OP_POP_JUMP_IF_FALSE);
         compile_block_body();
         emit(OP_LOOP_CONTINUE, -1, true);
@@ -848,7 +851,9 @@ __LISTCOMP:
             if(match_end_stmt()){
                 emit(OP_LOAD_NONE);
             }else{
-                EXPR_TUPLE();
+                co()->_rvalue = true;
+                EXPR_TUPLE();   // return value
+                co()->_rvalue = false;
                 consume_end_stmt();
             }
             emit(OP_RETURN_VALUE, -1, true);
diff --git a/tests/t1.py b/tests/t1.py
index 4a5d1f56..f59c9136 100644
--- a/tests/t1.py
+++ b/tests/t1.py
@@ -13,4 +13,8 @@ def test(n):
       k += 1
   return k
 
+# from dis import dis
+# dis(test)
+# dis(is_prime)
+
 print(test(10000))
\ No newline at end of file