Disclosed here are methods, systems, paradigms and structures for optimizing intermediate representation (IR) of a script code for fast path execution. A fast path is typically a path that handles most commonly occurring tasks more efficiently than less commonly occurring ones which are handled by slow paths. The less commonly occurring tasks may include uncommon cases, error handling, and other anomalies. The IR includes checkpoints which evaluate to two possible values resulting in either a fast path or slow path execution. The IR is optimized for fast path execution by regenerating a checkpoint as a labeled checkpoint. The code in the portion of the IR following the checkpoint is optimized assuming the checkpoint evaluates to a value resulting in fast path. The code for handling situations where the checkpoint evaluates to a value resulting in slow path is transferred to a portion of the IR identified by the label.