[PATCH] D43293: [SimplifyCFG] Don't remove preheaders when we need canonical loops.

[Serguei Katkov via Phabricator via llvm-commits]

skatkov added a comment.

Does it eliminate your regression?
I double the Eli's question: "What passes benefit from having SimplifyCFG keep around empty preheaders?"



================
Comment at: lib/Transforms/Utils/SimplifyCFG.cpp:5747
+  // introduce new backedge, so we can eliminate BB.
   bool NeedCanonicalLoop =
+      Options.NeedCanonicalLoop && LoopHeaders &&
----------------
It becomes complicated. Could you please re-write it in a more readable way?

I guess lambda with explicit ifs and possible comments may do things cleaner in terms of reading this.


https://reviews.llvm.org/D43293