if e.s.f.pass.debug > regDebug {
		fmt.Printf("edge %s->%s\n", e.p, e.b)
	}

	// Clear state.
	for _, vid := range e.cachedVals {
		delete(e.cache, vid)
	}
	e.cachedVals = e.cachedVals[:0]
	for k := range e.contents {
		delete(e.contents, k)
	}
	e.usedRegs = 0
	e.uniqueRegs = 0
	e.finalRegs = 0
	e.rematerializeableRegs = 0