change = phielimValue(v) || change
			}
		}
		if !change {
			break
		}
	}
}

// phielimValue tries to convert the phi v to a copy.
func phielimValue(v *Value) bool {
	if v.Op != OpPhi {
		return false
	}

	// If there are two distinct args of v which
	// are not v itself, then the phi must remain.
	// Otherwise, we can replace it with a copy.
	var w *Value
	for _, x := range v.Args {

		Bloc("b2",
			Valu("v3", OpConst64, c.config.Types.Int64, 3, nil),
			Goto("b4")),
		Bloc("b3",
			Valu("v4", OpConst64, c.config.Types.Int64, 4, nil),
			Goto("b4")),
		Bloc("b4",
			Valu("merge", OpPhi, c.config.Types.Int64, 0, nil, "v3", "v4"),
			Exit("mem")))
	sccp(fun.f)
	CheckFunc(fun.f)
	for _, b := range fun.blocks {
		for _, v := range b.Values {
			if v == fun.values["merge"] {
				if !isConst(v) {

	}

	// Compute transitive closure of live values.
	for len(q) > 0 {
		// pop a reachable value
		v := q[len(q)-1]
		q[len(q)-1] = nil
		q = q[:len(q)-1]
		for i, x := range v.Args {
			if v.Op == OpPhi && !reachable[v.Block.Preds[i].b.ID] {
				continue
			}
			if !live[x.ID] {
				live[x.ID] = true
				q = append(q, x) // push
				if x.Pos.IsStmt() != src.PosNotStmt {

				printed[v.ID] = true
			}
			p.endBlock(b, reachable[b.ID])
			continue
		}

		// print phis first since all value cycles contain a phi
		n := 0
		for _, v := range b.Values {
			if v.Op != OpPhi {
				continue
			}
			p.value(v, live[v.ID])
			printed[v.ID] = true
			n++
		}

		// print rest of values in dependency order
		for n < len(b.Values) {
			m := n
		outer:

	// equivalent(v, w):
	//   v.op == w.op
	//   v.type == w.type
	//   v.aux == w.aux
	//   v.auxint == w.auxint
	//   len(v.args) == len(w.args)
	//   v.block == w.block if v.op == OpPhi
	//   equivalent(v.args[i], w.args[i]) for i in 0..len(v.args)-1

	// The algorithm searches for a partition of f's values into
	// equivalence classes using the above definition.

			Goto("checkPtr")),
		Bloc("b2",
			Valu("ptr2", OpAddr, ptrType, 0, nil, "sb"),
			Goto("checkPtr")),
		// both ptr1 and ptr2 are guaranteed non-nil here
		Bloc("checkPtr",
			Valu("phi", OpPhi, ptrType, 0, nil, "ptr1", "ptr2"),
			Valu("bool2", OpIsNonNil, c.config.Types.Bool, 0, nil, "phi"),
			If("bool2", "extra", "exit")),
		Bloc("extra",
			Goto("exit")),
		Bloc("exit",
			Exit("mem")))

				ft.update(b, v, v.Args[1], unsigned, lt)
			case OpPhi:
				// Determine the min and max value of OpPhi composed entirely of integer constants.
				//
				// For example, for an OpPhi:
				//
				// v1 = OpConst64 [13]
				// v2 = OpConst64 [7]
				// v3 = OpConst64 [42]
				//
				// v4 = OpPhi(v1, v2, v3)
				//
				// We can prove:
				//
				// v4 >= 7 && v4 <= 42

			Valu("sb", OpSB, c.config.Types.Uintptr, 0, nil),
			Valu("v", OpConstBool, c.config.Types.Bool, 1, nil),
			Valu("addr", OpAddr, ptrType, 0, nil, "sb"),
			Goto("loop")),
		Bloc("loop",
			Valu("phi", OpPhi, types.TypeMem, 0, nil, "start", "store"),
			Valu("store", OpStore, types.TypeMem, 0, c.config.Types.Bool, "addr", "v", "phi"),
			If("v", "loop", "exit")),
		Bloc("exit",
			Exit("store")))

	CheckFunc(fun.f)

			for _, e := range b.Preds[1:] {
				p := e.b
				if end[p.ID] != flag {
					f.Fatalf("live flag in %s's predecessors not consistent", b)
				}
			}
		}
		for _, v := range oldSched {
			if v.Op == OpPhi && v.Type.IsFlags() {
				f.Fatalf("phi of flags not supported: %s", v.LongString())
			}

			// If v will be spilled, and v uses memory, then we must split it
			// into a load + a flag generator.

// The returned value, if non-nil, will be memory-typed (or a tuple with a memory-typed second part).
// Otherwise, nil is returned.
func (v *Value) MemoryArg() *Value {
	if v.Op == OpPhi {
		v.Fatalf("MemoryArg on Phi")
	}
	na := len(v.Args)
	if na == 0 {
		return nil
	}
	if m := v.Args[na-1]; m.Type.IsMemory() {
		return m
	}
	return nil
}