[llvm] [CodeGen] Remove `applySplitCriticalEdges` in `MachineDominatorTree` (PR #97055)

[Nikita Popov via llvm-commits]

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@@ -1338,9 +1340,17 @@ MachineBasicBlock *MachineBasicBlock::SplitCriticalEdge(
     LIS->repairIntervalsInRange(this, getFirstTerminator(), end(), UsedRegs);
   }
 
-  if (auto *MDTWrapper =
-          P.getAnalysisIfAvailable<MachineDominatorTreeWrapperPass>())
-    MDTWrapper->getDomTree().recordSplitCriticalEdge(this, Succ, NMBB);
+  auto *MDTWrapper =
+      P.getAnalysisIfAvailable<MachineDominatorTreeWrapperPass>();
+  auto *MPDTWrapper =
+      P.getAnalysisIfAvailable<MachinePostDominatorTreeWrapperPass>();
+  auto *MDT = MDTWrapper ? &MDTWrapper->getDomTree() : nullptr;
+  auto *MPDT = MPDTWrapper ? &MPDTWrapper->getPostDomTree() : nullptr;
+  MachineDomTreeUpdater MDTU(MDT, MPDT,
+                             MachineDomTreeUpdater::UpdateStrategy::Eager);
+  MDTU.applyUpdates({{MachineDominatorTree::Insert, this, NMBB},
+                     {MachineDominatorTree::Insert, NMBB, Succ},
+                     {MachineDominatorTree::Delete, this, Succ}});
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nikic wrote:

This means that you are now doing DT updates for critical edge splitting one by one, instead of batching many together.

https://github.com/llvm/llvm-project/pull/97055