is
Answer whether this operation is a placeholder, and should be replaced using the L2Regenerator. Placeholder instructions (like L2_VIRTUAL_CREATE_LABEL) are free to be moved through much of the control flow graph, even though the subgraphs they eventually get replaced by would be too complex to move. The mobility of placeholder instructions is essential to postponing stack reification and label creation into off-ramps (reification Zones) as much as possible.
Return
Whether the L2Instruction using this operation is a placeholder, subject to later substitution.