a.inPtrScalarBits += b.inPtrScalarBits

	a.tinyAllocCount += b.tinyAllocCount
	a.largeAlloc += b.largeAlloc
	a.largeAllocCount += b.largeAllocCount
	for i := range b.smallAllocCount {
		a.smallAllocCount[i] += b.smallAllocCount[i]
	}
	a.largeFree += b.largeFree
	a.largeFreeCount += b.largeFreeCount
	for i := range b.smallFreeCount {
		a.smallFreeCount[i] += b.smallFreeCount[i]
	}
}

	// Calculate derived stats.
	a.totalAllocs = a.largeAllocCount
	a.totalFrees = a.largeFreeCount
	a.totalAllocated = a.largeAlloc
	a.totalFreed = a.largeFree
	for i := range a.smallAllocCount {
		na := a.smallAllocCount[i]
		nf := a.smallFreeCount[i]
		a.totalAllocs += na
		a.totalFrees += nf
		a.totalAllocated += na * uint64(class_to_size[i])
		a.totalFreed += nf * uint64(class_to_size[i])
	}