//      the read-only data section.
		//   b. If it is a reflect-allocated type, it points into the Go heap.
		//      Reflect is responsible for keeping a reference to
		//      the underlying type so it won't be GCd.
		// If we ever have a moving GC, we need to change this for 2b (as
		// well as scan itabs to update their itab._type fields).
		bv.Set(int32(off/int64(types.PtrSize) + 1)) // pointer in second slot

	case types.TSLICE:

	if skip(gcd) {
		return nil
	}
	key := gcd.Key.Copy(fn, skip)
	if key == nil {
		return fn(gcd)
	}
	gcd = &GlobalCDtor{Ctor: gcd.Ctor, Key: key}
	if r := fn(gcd); r != nil {
		return r
	}
	return gcd
}

func (gcd *GlobalCDtor) GoString() string {
	return gcd.goString(0, "")
}

typically count the number of assignments instead of swaps:
E.g. the optimal algorithm of Dudzinski and Dydek for in-place
rotations uses O(u + v + gcd(u,v)) assignments which is
better than our O(3 * (u+v)) as gcd(u,v) <= u.


Stable sorting by SymMerge and BlockSwap rotations

SymMerg complexity for same size input M = N:
Calls to Less:  O(M*log(N/M+1)) = O(N*log(2)) = O(N)

// all the ellipses sizes.
func getDivisibleSize(totalSizes []uint64) (result uint64) {
	gcd := func(x, y uint64) uint64 {
		for y != 0 {
			x, y = y, x%y
		}
		return x
	}
	result = totalSizes[0]
	for i := 1; i < len(totalSizes); i++ {
		result = gcd(result, totalSizes[i])
	}
	return result
}

// isValidSetSize - checks whether given count is a valid set size for erasure coding.

	})
}

// greatest common divisor of x and y
func gcd(x, y int) int {
	var tmp int
	for {
		tmp = x % y
		if tmp > 0 {
			x = y
			y = tmp
		} else {
			return y
		}
	}
}

// least common multiple of x and y
func lcm(x, y int) int {
	return x * y / gcd(x, y)
}

// NetworkGatewaySet is a helper to manage a set of NetworkGateway instances.

    //     moved at that point. Otherwise, we can rotate the cycle a[1], a[1 + d], a[1 + 2d], etc,
    //     then a[2] etc, and so on until we have rotated all elements. There are gcd(d, n) cycles
    //     in all.
    // (3) "Successive". We can consider that we are exchanging a block of size d (a[0..d-1]) with a
    //     block of size n-d (a[d..n-1]), where in general these blocks have different sizes. If we

// The algorithm needs O((M+N)*log(M)) calls to data.Swap.
//
// The paper gives O((M+N)*log(M)) as the number of assignments assuming a
// rotation algorithm which uses O(M+N+gcd(M+N)) assignments. The argumentation
// in the paper carries through for Swap operations, especially as the block
// swapping rotate uses only O(M+N) Swaps.
//
// symMerge assumes non-degenerate arguments: a < m && m < b.

    //     moved at that point. Otherwise, we can rotate the cycle a[1], a[1 + d], a[1 + 2d], etc,
    //     then a[2] etc, and so on until we have rotated all elements. There are gcd(d, n) cycles
    //     in all.
    // (3) "Successive". We can consider that we are exchanging a block of size d (a[0..d-1]) with a
    //     block of size n-d (a[d..n-1]), where in general these blocks have different sizes. If we

// The algorithm needs O((M+N)*log(M)) calls to data.Swap.
//
// The paper gives O((M+N)*log(M)) as the number of assignments assuming a
// rotation algorithm which uses O(M+N+gcd(M+N)) assignments. The argumentation
// in the paper carries through for Swap operations, especially as the block
// swapping rotate uses only O(M+N) Swaps.
//
// symMerge assumes non-degenerate arguments: a < m && m < b.

		fuzzArg = []string{"-test.fuzzcachedir=" + fuzzCacheDir}
	}
	coverdirArg := []string{}
	addToEnv := ""
	if cfg.BuildCover {
		gcd := filepath.Join(a.Objdir, "gocoverdir")
		if err := sh.Mkdir(gcd); err != nil {
			// If we can't create a temp dir, terminate immediately
			// with an error as opposed to returning an error to the
			// caller; failed MkDir most likely indicates that we're