// otherwise the operations below will add mappings in an
			// arbitrary order.
			pm.mapMapping(src.Mapping[0])
		}

		for _, s := range src.Sample {
			if !isZeroSample(s) {
				pm.mapSample(s)
			}
		}
	}

	for _, s := range p.Sample {
		if isZeroSample(s) {
			// If there are any zero samples, re-merge the profile to GC
			// them.
			return Merge([]*Profile{p})
		}
	}

	return p, nil
}

			// otherwise the operations below will add mappings in an
			// arbitrary order.
			pm.mapMapping(src.Mapping[0])
		}

		for _, s := range src.Sample {
			if !isZeroSample(s) {
				pm.mapSample(s)
			}
		}
	}

	for _, s := range p.Sample {
		if isZeroSample(s) {
			// If there are any zero samples, re-merge the profile to GC
			// them.
			return Merge([]*Profile{p})
		}
	}

	return p, nil
}