Creates a new insertion point which doesn't point to anything.

Default constructor

Operands to be added to the instruction.

Constructor for the mapping of an instruction. \p NumOperands must be equal to number of all the operands of the related instruction. The rationale is

InvalidatePHILiveOutRegInfo - Invalidates a PHI's LiveOutInfo, to be called when a block is visited before all of its predecessors.

This method query the target whether it is beneficial for dag combiner to promote the specified node. If true, it should return the desired promotion

IsReachable - Checks if SU is reachable from TargetSU.

Called when a virtual register is no longer used. Return false to defer its deletion from LiveIntervals.

Called after cloning a virtual register. This is used for new registers representing connected components of Old.

Called immediately before erasing a dead machine instruction.

Called before shrinking the live range of a virtual register.

Constructs an unitialized set. init() needs to be called to initialize it.