[FunctionAttrs] Extract a helper function for the core logic used to

[oota-llvm.git] / lib / Transforms / Utils / BasicBlockUtils.cpp

diff --git a/lib/Transforms/Utils/BasicBlockUtils.cpp b/lib/Transforms/Utils/BasicBlockUtils.cpp
index 74ca0a1aa18b908169d05110b02eceeb1d620066..d59eef37da6ff5a7189e3fd89a3096a83995b7c2 100644 (file)
--- a/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -41,8 +41,8 @@ void llvm::DeleteDeadBlock(BasicBlock *BB) {
 
   // Loop through all of our successors and make sure they know that one
   // of their predecessors is going away.
-  for (unsigned i = 0, e = BBTerm->getNumSuccessors(); i != e; ++i)
-    BBTerm->getSuccessor(i)->removePredecessor(BB);
+  for (BasicBlock *Succ : BBTerm->successors())
+    Succ->removePredecessor(BB);
 
   // Zap all the instructions in the block.
   while (!BB->empty()) {
@@ -117,8 +117,9 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, DominatorTree *DT,
 
   // Don't break self-loops.
   if (PredBB == BB) return false;
-  // Don't break invokes.
-  if (isa<InvokeInst>(PredBB->getTerminator())) return false;
+  // Don't break unwinding instructions.
+  if (PredBB->getTerminator()->isExceptional())
+    return false;
 
   succ_iterator SI(succ_begin(PredBB)), SE(succ_end(PredBB));
   BasicBlock *OnlySucc = BB;
@@ -283,7 +284,7 @@ llvm::SplitAllCriticalEdges(Function &F,
 BasicBlock *llvm::SplitBlock(BasicBlock *Old, Instruction *SplitPt,
                              DominatorTree *DT, LoopInfo *LI) {
   BasicBlock::iterator SplitIt = SplitPt;
-  while (isa<PHINode>(SplitIt) || isa<LandingPadInst>(SplitIt))
+  while (isa<PHINode>(SplitIt) || SplitIt->isEHPad())
     ++SplitIt;
   BasicBlock *New = Old->splitBasicBlock(SplitIt, Old->getName()+".split");
 
@@ -474,6 +475,10 @@ BasicBlock *llvm::SplitBlockPredecessors(BasicBlock *BB,
                                          ArrayRef<BasicBlock *> Preds,
                                          const char *Suffix, DominatorTree *DT,
                                          LoopInfo *LI, bool PreserveLCSSA) {
+  // Do not attempt to split that which cannot be split.
+  if (!BB->canSplitPredecessors())
+    return nullptr;
+
   // For the landingpads we need to act a bit differently.
   // Delegate this work to the SplitLandingPadPredecessors.
   if (BB->isLandingPad()) {