Hummingbird in SGS2 (this was before rename to Exynos) and A4 in iPhone 4 stem from cooperation between Samsung and Apple (who previously used Samsung SoC in iPhone 3G and I think in 2G). The teams split before both phones reached maturity in design. From then on Samsung kept iterating on the Hummingbird design till I think quite recently - I'm not sure if my Note 10+ doesn't still have cores derived from that design.