// into equivalence classes (Types that compare CMPeq) matters.
func (t *Type) Compare(x *Type) Cmp {
	if x == t {
		return CMPeq
	}
	return t.cmp(x)
}

func cmpForNe(x bool) Cmp {
	if x {
		return CMPlt
	}
	return CMPgt
}

func (r *Sym) cmpsym(s *Sym) Cmp {
	if r == s {
		return CMPeq
	}
	if r == nil {
		return CMPlt
	}
	if s == nil {

	a := []*Type{
		TypeInvalid,
		TypeMem,
		TypeFlags,
		TypeVoid,
		TypeInt128,
	}
	for _, x := range a {
		for _, y := range a {
			c := x.Compare(y)
			if x == y && c != CMPeq || x != y && c == CMPeq {
				t.Errorf("%s compare %s == %d\n", x.extra, y.extra, c)
			}
		}
	}

		if tc := v.Type.Compare(w.Type); tc != types.CMPeq {
			return tc
		}
	}

	if v.Aux != w.Aux {
		if v.Aux == nil {
			return types.CMPlt
		}
		if w.Aux == nil {
			return types.CMPgt
		}
		return lt2Cmp(auxIDs[v.Aux] < auxIDs[w.Aux])
	}

	return types.CMPeq
}

// Sort values to make the initial partition.
type sortvalues struct {

			// the spill location.
			var name LocalSlot
			if v.Op == OpStoreReg {
				name = names[v.Args[0].ID]
			} else {
				name = names[v.ID]
			}
			if name.N != nil && v.Type.Compare(name.Type) == types.CMPeq {
				for _, id := range s.interfere[v.ID] {
					h := f.getHome(id)
					if h != nil && h.(LocalSlot).N == name.N && h.(LocalSlot).Off == name.Off {
						// A variable can interfere with itself.

	// The goal here is stability in the face
	// of unrelated changes elsewhere in the compiler.
	if c := x.AuxInt - y.AuxInt; c != 0 {
		return c < 0
	}
	if cmp := x.Type.Compare(y.Type); cmp != types.CMPeq {
		return cmp == types.CMPlt
	}
	return x.ID < y.ID
}

func (op Op) isLoweredGetClosurePtr() bool {
	switch op {

(Load <t1> p1 (Store {t2} p2 x _))
	&& isSamePtr(p1, p2)
	&& t1.Compare(x.Type) == types.CMPeq
	&& t1.Size() == t2.Size()
	=> x
(Load <t1> p1 (Store {t2} p2 _ (Store {t3} p3 x _)))
	&& isSamePtr(p1, p3)
	&& t1.Compare(x.Type) == types.CMPeq
	&& t1.Size() == t2.Size()
	&& disjoint(p3, t3.Size(), p2, t2.Size())
	=> x

(Eq32 x y) => (SGTU (MOVVconst [1]) (XOR (ZeroExt32to64 x) (ZeroExt32to64 y)))
(Eq64 x y) => (SGTU (MOVVconst [1]) (XOR x y))
(EqPtr x y) => (SGTU (MOVVconst [1]) (XOR x y))
(Eq(32|64)F x y) => (FPFlagTrue (CMPEQ(F|D) x y))

(Neq8 x y)  => (SGTU (XOR (ZeroExt8to64 x) (ZeroExt8to64 y)) (MOVVconst [0]))
(Neq16 x y) => (SGTU (XOR (ZeroExt16to32 x) (ZeroExt16to64 y)) (MOVVconst [0]))

(EqPtr x y) => (SGTUconst [1] (XOR x y))
(Eq(32|64)F x y) => (FPFlagTrue (CMPEQ(F|D) x y))

(Neq8 x y)  => (SGTU (XOR (ZeroExt8to32 x) (ZeroExt8to32 y)) (MOVWconst [0]))
(Neq16 x y) => (SGTU (XOR (ZeroExt16to32 x) (ZeroExt16to32 y)) (MOVWconst [0]))
(Neq32 x y) => (SGTU (XOR x y) (MOVWconst [0]))
(NeqPtr x y) => (SGTU (XOR x y) (MOVWconst [0]))
(Neq(32|64)F x y) => (FPFlagFalse (CMPEQ(F|D) x y))

(Less8 x y)  => (SGT (SignExt8to32 y) (SignExt8to32 x))

(Eq32 x y) => (SGTU (MOVVconst [1]) (XOR (ZeroExt32to64 x) (ZeroExt32to64 y)))
(Eq64 x y) => (SGTU (MOVVconst [1]) (XOR x y))
(EqPtr x y) => (SGTU (MOVVconst [1]) (XOR x y))
(Eq(32|64)F x y) => (FPFlagTrue (CMPEQ(F|D) x y))

(Neq8 x y)  => (SGTU (XOR (ZeroExt8to64 x) (ZeroExt8to64 y)) (MOVVconst [0]))
(Neq16 x y) => (SGTU (XOR (ZeroExt16to32 x) (ZeroExt16to64 y)) (MOVVconst [0]))

	SCASD:     "scas",
	SCASQ:     "scas",
	SCASW:     "scas",
	STOSB:     "stos",
	STOSD:     "stos",
	STOSQ:     "stos",
	STOSW:     "stos",
	XLATB:     "xlat",
}

var cmppsOps = []string{
	"cmpeq",
	"cmplt",
	"cmple",
	"cmpunord",
	"cmpneq",
	"cmpnlt",
	"cmpnle",
	"cmpord",
}

var pclmulqOps = []string{
	"pclmullqlqdq",
	"pclmulhqlqdq",
	"pclmullqhqdq",
	"pclmulhqhqdq",