[Mlir-commits] [mlir] [mlir][bufferization] Relax happens-before analysis for unstructured CF (PR #223006)

[Colin De Vlieghere]

Cubevoid wrote:

> > If you are apprehensive about the CFGLoopInfo addition, I am happy to first submit a simpler patch where it just checks reachability without considering parent loops.
> 
> That would help. I am not familiar with `CFGLoopInfo`.

Sounds good, I've created the simpler version here: https://github.com/llvm/llvm-project/pull/223777

The simpler version does not do any loop analysis and so is more conservative on regions with nested CF loops.

`CFGLoopInfo` turns out to actually just be a wrapper over LLVM's `llvm::LoopInfoBase`, see `llvm/include/llvm/Support/GenericLoopInfo.h`. It is able to recognize "natural loops" within a CFG, so irreducible CFGs will not be mistakenly treated as a loop in this analysis.

https://github.com/llvm/llvm-project/pull/223006