Well, even without taking into account that 32-bit systems are increasingly becoming extinct, it's less catastrophic than one might think. You get four muls ins

Well, even without taking into account that 32-bit systems are increasingly becoming extinct, it's less catastrophic than one might think. You get four muls instead of one and then a little carry propagation; I guess less if you have 32x32 -> 64 muls available? (I haven't thought deeply about it.) Certainly anything that relies on AES-NI would be much worse. But I guess your best shot in Murmur3, then.