[PATCH] D92200: Ensure SplitEdge to return the new block between the two given blocks

[Hongtao Yu via Phabricator via llvm-commits]

hoy added inline comments.


================
Comment at: llvm/lib/Transforms/Utils/BasicBlockUtils.cpp:512
     assert(SP == BB && "CFG broken");
     SP = nullptr;
+    return SplitBlock(Succ, &Succ->front(), DT, LI, MSSAU, "", /*Before=*/true);
----------------
Nit: Is resetting `SP` still needed?


================
Comment at: llvm/lib/Transforms/Utils/BasicBlockUtils.cpp:595
+  if (DT) {
+    DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Lazy);
+    SmallVector<DominatorTree::UpdateType, 8> DTUpdates;
----------------
Can we just change the dominator tree edges directly instead of going through the dominator updater?

like 

```
OldIdom = OldNode->getIDom();
DT->changeImmediateDominator(OldNode, NewNode);
DT->changeImmediateDominator(NewNode, OldIdom)
```




Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D92200/new/

https://reviews.llvm.org/D92200