(Rsh8x32  <t> x y) && !shiftIsBounded(v) => (SRA  <t> (SignExt8to64  x) (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] (ZeroExt32to64 y)))))
(Rsh8x64  <t> x y) && !shiftIsBounded(v) => (SRA  <t> (SignExt8to64  x) (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] y))))

		{"(y&x)&x", func(x, y int8) int8 { return (y & x) & x }, and},
		{"x^(x^y)", func(x, y int8) int8 { return x ^ (x ^ y) }, y},
		{"x^(y^x)", func(x, y int8) int8 { return x ^ (y ^ x) }, y},
		{"(x^y)^x", func(x, y int8) int8 { return (x ^ y) ^ x }, y},
		{"(y^x)^x", func(x, y int8) int8 { return (y ^ x) ^ x }, y},
		{"-(y-x)", func(x, y int8) int8 { return -(y - x) }, func(x, y int8) int8 { return x - y }},

	// Interpretation of trace:
	//   x ≡ y    attempt to unify types x and y
	//   p ➞ y    type parameter p is set to type y (p is inferred to be y)
	//   p ⇄ q    type parameters p and q match (p is inferred to be q and vice versa)
	//   x ≢ y    types x and y cannot be unified
	//   [p, q, ...] ➞ [x, y, ...]    mapping from type parameters to types
	traceInference = false
)

(Div64 x y) => (DIVV x y)
(Div64u ...) => (DIVVU ...)
(Div32 x y) => (DIVV (SignExt32to64 x) (SignExt32to64 y))
(Div32u x y) => (DIVVU (ZeroExt32to64 x) (ZeroExt32to64 y))
(Div16 x y) => (DIVV (SignExt16to64 x) (SignExt16to64 y))
(Div16u x y) => (DIVVU (ZeroExt16to64 x) (ZeroExt16to64 y))
(Div8 x y) => (DIVV (SignExt8to64 x) (SignExt8to64 y))
(Div8u x y) => (DIVVU (ZeroExt8to64 x) (ZeroExt8to64 y))
(Div(32|64)F ...) => (DIV(F|D) ...)

		if y, ok := y.(*Basic); ok {
			return x.kind == y.kind
		}

	case *Array:
		// Two array types are identical if they have identical element types
		// and the same array length.
		if y, ok := y.(*Array); ok {
			// If one or both array lengths are unknown (< 0) due to some error,
			// assume they are the same to avoid spurious follow-on errors.
			return (x.len < 0 || y.len < 0 || x.len == y.len) && c.identical(x.elem, y.elem, p)

(Div8 x y) => (Select1 (DIVV (SignExt8to64 x) (SignExt8to64 y)))
(Div8u x y) => (Select1 (DIVVU (ZeroExt8to64 x) (ZeroExt8to64 y)))
(Div(32|64)F ...) => (DIV(F|D) ...)

(Mod64 x y) => (Select0 (DIVV x y))
(Mod64u x y) => (Select0 (DIVVU x y))
(Mod32 x y) => (Select0 (DIVV (SignExt32to64 x) (SignExt32to64 y)))
(Mod32u x y) => (Select0 (DIVVU (ZeroExt32to64 x) (ZeroExt32to64 y)))
(Mod16 x y) => (Select0 (DIVV (SignExt16to64 x) (SignExt16to64 y)))

// the pixel at (x, y).
func (p *Gray) PixOffset(x, y int) int {
	return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*1
}

func (p *Gray) Set(x, y int, c color.Color) {
	if !(Point{x, y}.In(p.Rect)) {
		return
	}
	i := p.PixOffset(x, y)
	p.Pix[i] = color.GrayModel.Convert(c).(color.Gray).Y
}

func (p *Gray) SetRGBA64(x, y int, c color.RGBA64) {
	if !(Point{x, y}.In(p.Rect)) {

  // y = x[2:6:2, 1:3, 1:3]
  // begin_mask = 1<<1 (ignore begin_index = 1)
  // end_mask = 1<<2 (ignore end_index = 2)
  y = StridedSlice(scope_, x, {2, 1, 1}, {6, 3, 3}, {2, 1, 1},
                   StridedSlice::BeginMask(1 << 1).EndMask(1 << 2));
  // y.shape = [2, 3, 3];
  RunTest(x, x_shape, y, {2, 3, 3});

  // y = [tf.newaxis, 2:6:2, 1:3, 1:3]
  y = StridedSlice(scope_, x, {0, 2, 1, 1}, {0, 6, 3, 3}, {1, 2, 1, 1},

	            ≤ x/y₁·S - x/y             [x₁S ≤ x]
	            = (x/y)·(y/y₁·S - 1)       [factor out x/y]
	            = (x/y)·((y - y₁·S)/y₁·S)  [move -1 into y/y₁·S fraction]
	            = (x/y)·(y₀/y₁·S)          [y - y₁·S = y₀]
	            = (x/y)·(1/y₁)·(y₀/S)      [factor out 1/y₁]
	            < (x/y)·(1/y₁)             [y₀ < S, so y₀/S < 1]
	            ≤ (x/y)·(2/T)              [y₁ ≥ T/2, so 1/y₁ ≤ 2/T]

  };

  /** The notion of equality used by AtomicDoubleArray */
  static boolean bitEquals(double x, double y) {
    return Double.doubleToRawLongBits(x) == Double.doubleToRawLongBits(y);
  }

  static void assertBitEquals(double x, double y) {
    assertEquals(Double.doubleToRawLongBits(x), Double.doubleToRawLongBits(y));
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNulls() {