preds := func(b *Block) []Edge { return b.Preds }
	succs := func(b *Block) []Edge { return b.Succs }

	//TODO: benchmark and try to find criteria for swapping between
	// dominatorsSimple and dominatorsLT
	return f.dominatorsLTOrig(f.Entry, preds, succs)
}

// dominatorsLTOrig runs Lengauer-Tarjan to compute a dominator tree starting at
// entry and using predFn/succFn to find predecessors/successors to allow

		fmt.Fprintf(&buf, ".%d: # %s\n", b.Index, b.comment(fset))
		for _, n := range b.Nodes {
			fmt.Fprintf(&buf, "\t%s\n", formatNode(fset, n))
		}
		if len(b.Succs) > 0 {
			fmt.Fprintf(&buf, "\tsuccs:")
			for _, succ := range b.Succs {
				fmt.Fprintf(&buf, " %d", succ.Index)
			}
			buf.WriteByte('\n')
		}
		buf.WriteByte('\n')
	}
	return buf.String()
}

		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
}

		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
	}

			}
		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 {

				return false
			}
			for i := range fb.Values {
				if !checkVal(fb.Values[i], gb.Values[i]) {
					return false
				}
			}
			if len(fb.Succs) != len(gb.Succs) {
				return false
			}
			for i := range fb.Succs {
				if !checkBlk(fb.Succs[i].b, gb.Succs[i].b) {
					return false
				}
			}
			if len(fb.Preds) != len(gb.Preds) {
				return false
			}
			for i := range fb.Preds {

	// In these cases, we can reconstruct what the value
	// of any phi in b must be in the successor blocks.

	if len(t.Preds) == 1 && len(t.Succs) == 1 &&
		len(u.Preds) == 1 && len(u.Succs) == 1 &&
		t.Succs[0].b == u.Succs[0].b && len(t.Succs[0].b.Preds) == 2 {
		// p   q
		//  \ /
		//   b
		//  / \
		// t   u
		//  \ /
		//   m
		//

		Stmt:  stmt,
	}
	block.Succs = block.succs2[:0]
	g.Blocks = append(g.Blocks, block)
	return block
}

func (b *builder) add(n ast.Node) {
	b.current.Nodes = append(b.current.Nodes, n)
}

// jump adds an edge from the current block to the target block,
// and sets b.current to nil.
func (b *builder) jump(target *Block) {
	b.current.Succs = append(b.current.Succs, target)
	b.current = nil
}

				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 {