bid = cid
				continue blockloop
			}
		}

		// Still nothing, pick the unscheduled successor block encountered most recently.
		for len(succs) > 0 {
			// Pop an element from the tail of the queue.
			cid := succs[len(succs)-1]
			succs = succs[:len(succs)-1]
			if !scheduled[cid] {
				bid = cid
				continue blockloop
			}
		}

		// Still nothing, pick any non-exit block.

	var ss0, ss1 *Block
	s0 := b.Succs[0].b
	i0 := b.Succs[0].i
	if s0.Kind != BlockPlain || !isEmpty(s0) {
		s0, ss0 = b, s0
	} else {
		ss0 = s0.Succs[0].b
		i0 = s0.Succs[0].i
	}
	s1 := b.Succs[1].b
	i1 := b.Succs[1].i
	if s1.Kind != BlockPlain || !isEmpty(s1) {
		s1, ss1 = b, s1
	} else {
		ss1 = s1.Succs[0].b
		i1 = s1.Succs[0].i
	}
	if ss0 != ss1 {

		return
	}
	ln.calculateDepths()
	b2l := ln.b2l
	for _, b := range ln.po {
		l := b2l[b.ID]
		if l != nil && len(b.Succs) == 2 {
			sl := b2l[b.Succs[0].b.ID]
			if recordIfExit(l, sl, b.Succs[0].b) {
				continue
			}
			sl = b2l[b.Succs[1].b.ID]
			if recordIfExit(l, sl, b.Succs[1].b) {
				continue
			}
		}
	}
	ln.initializedExits = true
}

			}
		case BlockRetJmp:
			if len(b.Succs) != 0 {
				f.Fatalf("retjmp block %s len(Succs)==%d, want 0", b, len(b.Succs))
			}
			if b.NumControls() != 1 {
				f.Fatalf("retjmp block %s has nil control", b)
			}
			if !b.Controls[0].Type.IsMemory() {
				f.Fatalf("retjmp block %s has non-memory control value %s", b, b.Controls[0].LongString())
			}
		case BlockPlain:
			if len(b.Succs) != 1 {

func (b *Block) removeSucc(i int) {
	n := len(b.Succs) - 1
	if i != n {
		e := b.Succs[n]
		b.Succs[i] = e
		// Update the other end of the edge we moved.
		e.b.Preds[e.i].i = i
	}
	b.Succs[n] = Edge{}
	b.Succs = b.Succs[:n]
	b.Func.invalidateCFG()
}

func (b *Block) swapSuccessors() {
	if len(b.Succs) != 2 {
		b.Fatalf("swapSuccessors with len(Succs)=%d", len(b.Succs))
	}
	e0 := b.Succs[0]

	case ssa.BlockPlain:
		if next != b.Succs[0].Block() {
			s.Br(obj.AJMP, b.Succs[0].Block())
		}

	case ssa.BlockIf:
		switch next {
		case b.Succs[0].Block():
			// if false, jump to b.Succs[1]
			getValue32(s, b.Controls[0])
			s.Prog(wasm.AI32Eqz)
			s.Prog(wasm.AIf)
			s.Br(obj.AJMP, b.Succs[1].Block())
			s.Prog(wasm.AEnd)
		case b.Succs[1].Block():
			// if true, jump to b.Succs[0]

		// reverse is the predecessor from which the truth value comes.
		var reverse int
		if b0.Succs[0].b == pb0 && b0.Succs[1].b == pb1 {
			reverse = 0
		} else if b0.Succs[0].b == pb1 && b0.Succs[1].b == pb0 {
			reverse = 1
		} else {
			b.Fatalf("invalid predecessors\n")
		}

		for _, v := range b.Values {
			if v.Op != OpPhi {
				continue
			}

			// Look for conversions from bool to 0/1.

		return false
	}
	yes, no := b.Succs[0].Block(), b.Succs[1].Block()
	if !isLeafPlain(yes) || len(yes.Values) > 1 || !canSpeculativelyExecute(yes) {
		return false
	}
	if !isLeafPlain(no) || len(no.Values) > 1 || !canSpeculativelyExecute(no) {
		return false
	}
	if b.Succs[0].Block().Succs[0].Block() != b.Succs[1].Block().Succs[0].Block() {
		return false
	}

// Z:
// 	return y
// }

// {f:BC_CD_BE_BZ_CZ101,
//  maxin:32, blocks:[]blo{
//  	blo{inc:0, cond:true, succs:[2]int64{1, 2}},
//  	blo{inc:1, cond:true, succs:[2]int64{2, 3}},
//  	blo{inc:0, cond:true, succs:[2]int64{1, 4}},
//  	blo{inc:10, cond:true, succs:[2]int64{1, 25}},
//  	blo{inc:0, cond:true, succs:[2]int64{2, 25}},}},

var labels string = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

		// order, in which the predecessors edges are merged here.
		p, i := b.Preds[0].b, b.Preds[0].i
		s, j := b.Succs[0].b, b.Succs[0].i
		ns := len(s.Preds)
		p.Succs[i] = Edge{s, j}
		s.Preds[j] = Edge{p, i}

		for _, e := range b.Preds[1:] {
			p, i := e.b, e.i
			p.Succs[i] = Edge{s, len(s.Preds)}
			s.Preds = append(s.Preds, Edge{p, i})
		}

		// Attempt to preserve a statement boundary
		if bIsStmt {