v.Aux = symToAux(mergeSym(sym1, sym2))
		v.AddArg2(ptr, mem)
		return true
	}
	// match: (MOVQstoreconst [c] {s} p1 x:(MOVQstoreconst [a] {s} p0 mem))
	// cond: config.useSSE && x.Uses == 1 && sequentialAddresses(p0, p1, int64(a.Off()+8-c.Off())) && a.Val() == 0 && c.Val() == 0 && setPos(v, x.Pos) && clobber(x)
	// result: (MOVOstoreconst [makeValAndOff(0,a.Off())] {s} p0 mem)
	for {
		c := auxIntToValAndOff(v.AuxInt)