[PATCH] D57316: [LoopSimplifyCFG] Work around bug in DTU by using lazy strategy

Wed Jan 30 07:57:44 PST 2019

kuhar added a comment.

In D57316#1377047 <https://reviews.llvm.org/D57316#1377047>, @mkazantsev wrote:

> It is indeed a bug in DTU, I was able to construct a unit test to reproduce it. https://bugs.llvm.org/show_bug.cgi?id=40528

You should use DTU.applyUpdates after a transformation that affects multiple CFG edges to inform DomTree about all of the things that changed since the last time it was updated. Eager strategy means that at each update point the updates are performed immediately, while the lazy update strategy is free to schedule them at any 'update' (synchronization) point between the first one and flush (possibly multiple time).
Perhaps we should improve the the documentation. @mkazantsev: do you have some suggestions?

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