// float
	{types.TFLOAT64, types.TFLOAT32}: {ssa.OpCvt64Fto32F, ssa.OpCopy, types.TFLOAT32},
	{types.TFLOAT64, types.TFLOAT64}: {ssa.OpRound64F, ssa.OpCopy, types.TFLOAT64},
	{types.TFLOAT32, types.TFLOAT32}: {ssa.OpRound32F, ssa.OpCopy, types.TFLOAT32},
	{types.TFLOAT32, types.TFLOAT64}: {ssa.OpCvt32Fto64F, ssa.OpCopy, types.TFLOAT64},
}

2.718281828459045   float32     2.718281828459045 rounds to 2.7182817 which is in the set of float32 values
-1e-1000            float64     -1e-1000 rounds to IEEE -0.0 which is further simplified to 0.0
0i                  int         0 is an integer value
(42 + 0i)           float32     42.0 (with zero imaginary part) is in the set of float32 values
</pre>

<pre>

	v_0 := v.Args[0]
	b := v.Block
	typ := &b.Func.Config.Types
	// match: (Neg32F x)
	// result: (PXOR x (MOVSSconst <typ.Float32> [float32(math.Copysign(0, -1))]))
	for {
		x := v_0
		v.reset(Op386PXOR)
		v0 := b.NewValue0(v.Pos, Op386MOVSSconst, typ.Float32)
		v0.AuxInt = float32ToAuxInt(float32(math.Copysign(0, -1)))
		v.AddArg2(x, v0)
		return true
	}
}
func rewriteValue386_OpNeg64F(v *Value) bool {

	typ := &b.Func.Config.Types
	// match: (Add32F x y)
	// result: (Select0 (FADDS x y))
	for {
		x := v_0
		y := v_1
		v.reset(OpSelect0)
		v0 := b.NewValue0(v.Pos, OpS390XFADDS, types.NewTuple(typ.Float32, types.TypeFlags))
		v0.AddArg2(x, y)
		v.AddArg(v0)
		return true
	}
}
func rewriteValueS390X_OpAdd64F(v *Value) bool {
	v_1 := v.Args[1]
	v_0 := v.Args[0]
	b := v.Block