Revert "[JumpThreading] Preservation of DT and LVI across the pass"

This reverts r321825, it causes crashes in Chromium. Reproducer
forthcoming.

llvm-svn: 321832

1 files changed, 4 insertions, 14 deletions

diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index 9d35939..056753f 100644
--- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -45,22 +45,16 @@
 
 using namespace llvm;
 
-void llvm::DeleteDeadBlock(BasicBlock *BB, DeferredDominance *DDT) {
+void llvm::DeleteDeadBlock(BasicBlock *BB) {
   assert((pred_begin(BB) == pred_end(BB) ||
          // Can delete self loop.
          BB->getSinglePredecessor() == BB) && "Block is not dead!");
   TerminatorInst *BBTerm = BB->getTerminator();
-  std::vector<DominatorTree::UpdateType> Updates;
 
   // Loop through all of our successors and make sure they know that one
   // of their predecessors is going away.
-  if (DDT)
-    Updates.reserve(BBTerm->getNumSuccessors());
-  for (BasicBlock *Succ : BBTerm->successors()) {
+  for (BasicBlock *Succ : BBTerm->successors())
     Succ->removePredecessor(BB);
-    if (DDT)
-      Updates.push_back({DominatorTree::Delete, BB, Succ});
-  }
 
   // Zap all the instructions in the block.
   while (!BB->empty()) {
@@ -75,12 +69,8 @@ void llvm::DeleteDeadBlock(BasicBlock *BB, DeferredDominance *DDT) {
     BB->getInstList().pop_back();
   }
 
-  if (DDT) {
-    DDT->applyUpdates(Updates);
-    DDT->deleteBB(BB); // Deferred deletion of BB.
-  } else {
-    BB->eraseFromParent(); // Zap the block!
-  }
+  // Zap the block!
+  BB->eraseFromParent();
 }
 
 void llvm::FoldSingleEntryPHINodes(BasicBlock *BB,