[llvm] 81afeac - [SimplifyCFGPass] mergeEmptyReturnBlocks(): skip blocks scheduled for removal as per DomTreeUpdater

[Roman Lebedev via llvm-commits]

Author: Roman Lebedev
Date: 2021-01-12T02:09:47+03:00
New Revision: 81afeacd379f160495718438d6dd5e9b848a169d

URL: https://github.com/llvm/llvm-project/commit/81afeacd379f160495718438d6dd5e9b848a169d
DIFF: https://github.com/llvm/llvm-project/commit/81afeacd379f160495718438d6dd5e9b848a169d.diff

LOG: [SimplifyCFGPass] mergeEmptyReturnBlocks(): skip blocks scheduled for removal as per DomTreeUpdater

Thus supporting lazy DomTreeUpdater mode,
where the domtree updates (and thus block removals)
aren't applied immediately, but are delayed
until last possible moment.

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
index 44b9ddd3e1ee..944331932495 100644
--- a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
+++ b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
@@ -86,8 +86,9 @@ static bool mergeEmptyReturnBlocks(Function &F, DomTreeUpdater *DTU) {
   BasicBlock *RetBlock = nullptr;
 
   // Scan all the blocks in the function, looking for empty return blocks.
-  for (Function::iterator BBI = F.begin(), E = F.end(); BBI != E; ) {
-    BasicBlock &BB = *BBI++;
+  for (BasicBlock &BB : make_early_inc_range(F)) {
+    if (DTU && DTU->isBBPendingDeletion(&BB))
+      continue;
 
     // Only look at return blocks.
     ReturnInst *Ret = dyn_cast<ReturnInst>(BB.getTerminator());