// compile

// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Various tests for expressions with high complexity.

package main

// Concatenate 16 4-bit integers into a 64-bit number.
func concat(s *[16]byte) uint64 {
	r := (((((((((((((((uint64(s[0])<<4|
		uint64(s[1]))<<4|
		uint64(s[2]))<<4|
		uint64(s[3]))<<4|
		uint64(s[4]))<<4|
		uint64(s[5]))<<4|
		uint64(s[6]))<<4|
		uint64(s[7]))<<4|
		uint64(s[8]))<<4|
		uint64(s[9]))<<4|
		uint64(s[10]))<<4|
		uint64(s[11]))<<4|
		uint64(s[12]))<<4|
		uint64(s[13]))<<4|
		uint64(s[14]))<<4 |
		uint64(s[15]))
	return r
}

// Compute the determinant of a 4x4-matrix by the sum
// over all index permutations.
func determinant(m [4][4]float64) float64 {
	return m[0][0]*m[1][1]*m[2][2]*m[3][3] -
		m[0][0]*m[1][1]*m[2][3]*m[3][2] -
		m[0][0]*m[1][2]*m[2][1]*m[3][3] +
		m[0][0]*m[1][2]*m[2][3]*m[3][1] +
		m[0][0]*m[1][3]*m[2][1]*m[3][2] -
		m[0][0]*m[1][3]*m[2][2]*m[3][1] -
		m[0][1]*m[1][0]*m[2][2]*m[3][3] +
		m[0][1]*m[1][0]*m[2][3]*m[3][2] +
		m[0][1]*m[1][2]*m[2][0]*m[3][3] -
		m[0][1]*m[1][2]*m[2][3]*m[3][0] -
		m[0][1]*m[1][3]*m[2][0]*m[3][2] +
		m[0][1]*m[1][3]*m[2][2]*m[3][0] +
		m[0][2]*m[1][0]*m[2][1]*m[3][3] -
		m[0][2]*m[1][0]*m[2][3]*m[3][1] -
		m[0][2]*m[1][1]*m[2][0]*m[3][3] +
		m[0][2]*m[1][1]*m[2][3]*m[3][0] +
		m[0][2]*m[1][3]*m[2][0]*m[3][1] -
		m[0][2]*m[1][3]*m[2][1]*m[3][0] -
		m[0][3]*m[1][0]*m[2][1]*m[3][2] +
		m[0][3]*m[1][0]*m[2][2]*m[3][1] +
		m[0][3]*m[1][1]*m[2][0]*m[3][2] -
		m[0][3]*m[1][1]*m[2][2]*m[3][0] -
		m[0][3]*m[1][2]*m[2][0]*m[3][1] +
		m[0][3]*m[1][2]*m[2][1]*m[3][0]
}

// A right-leaning tree of byte multiplications.
func righttree(a, b, c, d uint8) uint8 {
	return a * (b * (c * (d *
		(a * (b * (c * (d *
			(a * (b * (c * (d *
				(a * (b * (c * (d *
					(a * (b * (c * (d *
						a * (b * (c * d)))))))))))))))))))))

}

// A left-leaning tree of byte multiplications.
func lefttree(a, b, c, d uint8) uint8 {
	return ((((((((((((((((((a * b) * c) * d *
		a) * b) * c) * d *
		a) * b) * c) * d *
		a) * b) * c) * d *
		a) * b) * c) * d *
		a) * b) * c) * d)
}

type T struct {
	Next I
}

type I interface{}

// A chains of type assertions.
func ChainT(t *T) *T {
	return t.
		Next.(*T).
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}

type U struct {
	Children []J
}

func (u *U) Child(n int) J { return u.Children[n] }

type J interface {
	Child(n int) J
}

func ChainUAssert(u *U) *U {
	return u.Child(0).(*U).
		Child(0).(*U).
		Child(0).(*U).
		Child(0).(*U).
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}

func ChainUNoAssert(u *U) *U {
	return u.Child(0).
		Child(0).
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}