[PATCH] D75977: [JumpThreading] Fix PR44611

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


================
Comment at: llvm/lib/Transforms/Scalar/JumpThreading.cpp:455
+      // We may hit cycles, just add it to Unreachable.
+      if (!DTU->getDomTree().isReachableFromEntry(&BB)) {
+        Unreachable.insert(&BB);
----------------
We've been trying to avoid calling getDomTree() in JumpThreading where possible because there's a performance cost: it actually flushes all the pending DomTree updates.  Calling it for every basic block will likely cause performance issues.  (You should be able to find some discussion of this in the review threads for the related JumpThreading patches.)


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D75977/new/

https://reviews.llvm.org/D75977