Use the getUniquePredecessor() utility function, instead of doing
what it does manually.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111248 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/BasicBlockUtils.cpp b/lib/Transforms/Utils/BasicBlockUtils.cpp
index ec625b4..c28b027 100644
--- a/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -97,23 +97,13 @@
/// 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.