Probably any early home rule bill could've done the trick. By early I mean well before WW1 - ideally, in the late 19c, at the same time people were mooting the concept of an Imperial federation. So you'd have Britain (later England, Scotland, and Wales), Ireland, Canada, Australia, New Zealand, and the Cape Colony as subnational entities of one state [EDIT: Newfoundland would've been a separate component, since it only joined Canada in 1949].
Giving home rule to just Ireland, without the dominions, is inherently unstable. We see this today in UK politics, where there's home rule in Scotland, Wales, and Northern Ireland. Since the vast majority of the UK population is in England, it leads to asymmetric devolution, which in turn leads to English Votes on English Laws ugliness. The only way out is devolution to the regions of England, but those don't always have as strong identities as do Wales, Scotland, and Ireland, and on top of that Labour totally botched the implementation. Something similar would've happened if the UK had given Ireland home rule in 1900 or so - there was plenty of anti-Irish racism, and within a few years you'd see British Votes on British Laws agitation. Scotland rejected independence recently, but it was close, and Scots do not face nearly the same hostility from England that the Irish did a hundred years ago.