diff options
| -rw-r--r-- | lib/Transforms/Utils/BasicBlockUtils.cpp | 20 |
1 files changed, 5 insertions, 15 deletions
diff --git a/lib/Transforms/Utils/BasicBlockUtils.cpp b/lib/Transforms/Utils/BasicBlockUtils.cpp index ec625b4cbb..c28b027556 100644 --- a/lib/Transforms/Utils/BasicBlockUtils.cpp +++ b/lib/Transforms/Utils/BasicBlockUtils.cpp @@ -97,23 +97,13 @@ bool llvm::DeleteDeadPHIs(BasicBlock *BB) { /// MergeBlockIntoPredecessor - Attempts to merge a block into its predecessor, /// if possible. The return value indicates success or failure. bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P) { - pred_iterator PI(pred_begin(BB)), PE(pred_end(BB)); - // Can't merge the entry block. Don't merge away blocks who have their - // address taken: this is a bug if the predecessor block is the entry node - // (because we'd end up taking the address of the entry) and undesirable in - // any case. - if (pred_begin(BB) == pred_end(BB) || - BB->hasAddressTaken()) return false; + // Don't merge away blocks who have their address taken. + if (BB->hasAddressTaken()) return false; - BasicBlock *PredBB = *PI++; - for (; PI != PE; ++PI) // Search all predecessors, see if they are all same - if (*PI != PredBB) { - PredBB = 0; // There are multiple different predecessors... - break; - } - - // Can't merge if there are multiple predecessors. + // Can't merge if there are multiple predecessors, or no predecessors. + BasicBlock *PredBB = BB->getUniquePredecessor(); if (!PredBB) return false; + // Don't break self-loops. if (PredBB == BB) return false; // Don't break invokes. |