diff --git a/dat/og/bt_rules60.txt b/dat/og/bt_rules60.txt
index f7a3fde8c..64d8db7c5 100644
--- a/dat/og/bt_rules60.txt
+++ b/dat/og/bt_rules60.txt
@@ -11,6 +11,7 @@ local_address, saving_stack, local_address, conversion_op, local_address, copyin
 create_struct =4, assigning, local_address, saving_stack =0, local, copying_to_acc => 6;
 intcondop, assigning, local, branchop => 7;
 realcondop, assigning, local, branchop => 7;
+nilcondop, assigning, local, branchop => 7;
 int_real_op, local_address, copying => 10;
 real_int_op, local_address, copying => 10;
 direct_call_op, inplacemark, copying => 12;
diff --git a/doc/todo.txt b/doc/todo.txt
index d6167af8f..494e144bb 100644
--- a/doc/todo.txt
+++ b/doc/todo.txt
@@ -19,7 +19,6 @@ In development:
   - pi under 6 sec
   - #601 : optimize: if (a == b) {} else {}
  --------------------------------------
-  - #601 : optimize: if (nil == name) {} else {}
 
   === Iteration 23 ===
   --------------------------------------
diff --git a/elenasrc3/engine/bcwriter.cpp b/elenasrc3/engine/bcwriter.cpp
index e3f369667..2032d0a26 100644
--- a/elenasrc3/engine/bcwriter.cpp
+++ b/elenasrc3/engine/bcwriter.cpp
@@ -585,7 +585,6 @@ void intLongOp(CommandTape& tape, BuildNode& node, TapeScope&)
       default:
          throw InternalError(errFatalError);
    }
-
 }
 
 void realIntOp(CommandTape& tape, BuildNode& node, TapeScope&)
@@ -2449,6 +2448,9 @@ inline bool nativeBranchingOp(BuildNode lastNode)
       case BuildKey::RealCondOp:
          branchNode.setKey(BuildKey::RealBranchOp);
          break;
+      case BuildKey::NilCondOp:
+         branchNode.setKey(BuildKey::NilRefBranchOp);
+         break;
       default:
          break;
    }
@@ -2881,6 +2883,11 @@ void ByteCodeWriter :: saveNativeBranching(CommandTape& tape, BuildNode node, Ta
          tape.write(ByteCode::CmpN, valueNode.arg.value);
          break;
       }
+      case BuildKey::NilRefBranchOp:
+         // NOTE : sp[0] - loperand
+         tape.write(ByteCode::PeekSI, 0);
+         tape.write(ByteCode::CmpR);
+         break;
       default:
          assert(false);
          break;
@@ -3414,6 +3421,7 @@ void ByteCodeWriter :: saveTape(CommandTape& tape, BuildNode node, TapeScope& ta
          case BuildKey::IntBranchOp:
          case BuildKey::IntConstBranchOp:
          case BuildKey::RealBranchOp:
+         case BuildKey::NilRefBranchOp:
             saveNativeBranching(tape, current, tapeScope, paths, tapeOptMode, loopMode);
             weakLoop = false;
             break;
diff --git a/elenasrc3/engine/buildtree.h b/elenasrc3/engine/buildtree.h
index 6f6a1435d..dd879f408 100644
--- a/elenasrc3/engine/buildtree.h
+++ b/elenasrc3/engine/buildtree.h
@@ -160,8 +160,9 @@ namespace elena_lang
       IntLongOp            = 0x0082,
       DistributedTypeList  = 0x0083,
       UnboxAndCallMessage  = 0x0084,
+      NilRefBranchOp       = 0x0085,
 
-      MaxOperationalKey    = 0x0084,
+      MaxOperationalKey    = 0x0085,
 
       Import               = 0x0090,
       DictionaryOp         = 0x0091,
@@ -335,6 +336,7 @@ namespace elena_lang
          map.add("local", BuildKey::Local);
          map.add("intcondop", BuildKey::IntCondOp);
          map.add("realcondop", BuildKey::RealCondOp);
+         map.add("nilcondop", BuildKey::NilCondOp);
          map.add("branchop", BuildKey::BranchOp);
          map.add("intbranchop", BuildKey::IntBranchOp);
          map.add("conversion_op", BuildKey::ConversionOp);
diff --git a/tests60/sandbox/sandbox.l b/tests60/sandbox/sandbox.l
index d0e3d3a95..d562358c8 100644
--- a/tests60/sandbox/sandbox.l
+++ b/tests60/sandbox/sandbox.l
@@ -1,28 +1,11 @@
 import extensions;
 
-class Object
-{
-   dispatch() => nil;
-}
-
-public interface Func
-{
-   abstract function();
-}
-
-singleton E
-{
-   callFromLambda()
-   {
-      var f := { callMe(); };
-
-      f();
-   }
-
-   private callMe(){}
-}
-
 public program()
 {
-   E.callFromLambda()
+   var name := nil;
+
+   if (nil == name) {
+      console.writeLine("name is nil")
+   } 
+   else console.printLine("name=",name)
 }
\ No newline at end of file