League of Legends (LoL) Question: Who wins?

rene wins always as long as the player is wearing crocs.

Renekton has an early game advantage until Irelia gets her Sheen + other component powerspike. It's still mostly a skill matchup since they both have good mobility, long stuns and fight-oriented ultimates.

Late game, Renekton falls off in utility to his team but he probably wins a 1v1, while Irelia would do better in teamfights and can somewhat hold off against a splitpush so she would most likely avoid the 1v1 and the game would be in her favour.

I haven't played as either of the champions, but I've played against them. If I'm not mistaken - irelia will start getting an advantage once she purchases Sheen in the early game. Late game if you are speaking of both being at a full build and same level with no external advantage - then I'm going to have to go with Renekton having the advantage.

idont really know but from personal preference rene always has the lane pressure if both knows how to play