copies map[*Value]bool

	loopnest *loopnest

	// choose a good order in which to visit blocks for allocation purposes.
	visitOrder []*Block

	// blockOrder[b.ID] corresponds to the index of block b in visitOrder.
	blockOrder []int32

	// whether to insert instructions that clobber dead registers at call sites
	doClobber bool
}

type endReg struct {
	r register