[PATCH] D154695: [Coroutines] Add an O(n) algorithm for computing the cross suspend point information.

[Matthias Braun via Phabricator via llvm-commits]

MatzeB added a comment.

I did spent some more time on the patch yesterday. I believe the indeterminism was somewhat triggered by the existing code in `BlockToIndexMapping`: https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/Coroutines/CoroFrame.cpp#L63 it sorts the blocks by their memory address and as memory address can fluctuate between runs (caused by ASLR etc.) iterating over the Mapping resulting in a nondeterministic order. This doesn't matter when the algorithm always reaches the same solution regardless of the order, but this wasn't the case after the rewrite it seems.

I also did prepare a proposal patch to use initial RPO pass + fixpoint worklist algorithm. Cleaning this up right now for submission / further discussion...


Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D154695