for i, b := range cov {
		b |= b >> 1
		b |= b >> 2
		b |= b >> 4
		b -= b >> 1
		coverageSnapshot[i] = b
	}
}

// diffCoverage returns a set of bits set in snapshot but not in base.
// If there are no new bits set, diffCoverage returns nil.
func diffCoverage(base, snapshot []byte) []byte {
	if len(base) != len(snapshot) {

				if c.warmupRun() {
					if shouldPrintDebugInfo() {
						c.debugLogf(
							"processed an initial input, id: %s, new bits: %d, size: %d, exec time: %s",
							result.entry.Parent,
							countBits(diffCoverage(c.coverageMask, result.coverageData)),
							len(result.entry.Data),
							result.entryDuration,
						)
					}
					c.updateCoverage(result.coverageData)
					c.warmupInputLeft--