[Mlir-commits] [llvm] [mlir] [LoopInfo] Store blocks using Euler tour representation (PR #211485)

[Fangrui Song]

MaskRay wrote:

> > LGTM. Not 100% convinced this is worth the complexity, though.
> 
> Thanks for the review! Agreed that instructions:u delta is marginal. The value is two structural points you mentioned: removing `PopulateLoopDFS` and shrinking deeply-nested-loop storage.
> 
> Removing `PopulateLoopDFS` may unlock further optimizations.

Building `LoopInfo` is only ~1~2% of an `opt -O2` run, so the return is small.

https://github.com/llvm/llvm-project/pull/211485