Don't allocate empty read-only SmallVectors during SelectionDAG deallocation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133348 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 11 insertions, 7 deletions

diff --git a/include/llvm/CodeGen/SelectionDAG.h b/include/llvm/CodeGen/SelectionDAG.h
index 1c42bef4a0..3ec5adabe6 100644
--- a/include/llvm/CodeGen/SelectionDAG.h
+++ b/include/llvm/CodeGen/SelectionDAG.h
@@ -96,8 +96,12 @@ public:
     return DbgValues.empty() && ByvalParmDbgValues.empty();
   }
 
-  SmallVector<SDDbgValue*,2> &getSDDbgValues(const SDNode *Node) {
-    return DbgValMap[Node];
+  ArrayRef<SDDbgValue*> getSDDbgValues(const SDNode *Node) {
+    DenseMap<const SDNode*, SmallVector<SDDbgValue*, 2> >::iterator I =
+      DbgValMap.find(Node);
+    if (I != DbgValMap.end())
+      return I->second;
+    return ArrayRef<SDDbgValue*>();
   }
 
   typedef SmallVector<SDDbgValue*,32>::iterator DbgIterator;
@@ -898,7 +902,7 @@ public:
   void AddDbgValue(SDDbgValue *DB, SDNode *SD, bool isParameter);
 
   /// GetDbgValues - Get the debug values which reference the given SDNode.
-  SmallVector<SDDbgValue*,2> &GetDbgValues(const SDNode* SD) {
+  ArrayRef<SDDbgValue*> GetDbgValues(const SDNode* SD) {
     return DbgInfo->getSDDbgValues(SD);
   }
 
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
index 0d656efb37..dbc623b01e 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
@@ -649,7 +649,7 @@ static void ProcessSDDbgValues(SDNode *N, SelectionDAG *DAG,
   // order number right after the N.
   MachineBasicBlock *BB = Emitter.getBlock();
   MachineBasicBlock::iterator InsertPos = Emitter.getInsertPos();
-  SmallVector<SDDbgValue*,2> &DVs = DAG->GetDbgValues(N);
+  ArrayRef<SDDbgValue*> DVs = DAG->GetDbgValues(N);
   for (unsigned i = 0, e = DVs.size(); i != e; ++i) {
     if (DVs[i]->isInvalidated())
       continue;
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 68eeb609d4..77ce54f809 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -598,7 +598,7 @@ void SelectionDAG::DeallocateNode(SDNode *N) {
   Ordering->remove(N);
 
   // If any of the SDDbgValue nodes refer to this SDNode, invalidate them.
-  SmallVector<SDDbgValue*, 2> &DbgVals = DbgInfo->getSDDbgValues(N);
+  ArrayRef<SDDbgValue*> DbgVals = DbgInfo->getSDDbgValues(N);
   for (unsigned i = 0, e = DbgVals.size(); i != e; ++i)
     DbgVals[i]->setIsInvalidated();
 }
@@ -5508,9 +5508,9 @@ void SelectionDAG::TransferDbgValues(SDValue From, SDValue To) {
     return;
   SDNode *FromNode = From.getNode();
   SDNode *ToNode = To.getNode();
-  SmallVector<SDDbgValue *, 2> &DVs = GetDbgValues(FromNode);
+  ArrayRef<SDDbgValue *> DVs = GetDbgValues(FromNode);
   SmallVector<SDDbgValue *, 2> ClonedDVs;
-  for (SmallVector<SDDbgValue *, 2>::iterator I = DVs.begin(), E = DVs.end();
+  for (ArrayRef<SDDbgValue *>::iterator I = DVs.begin(), E = DVs.end();
        I != E; ++I) {
     SDDbgValue *Dbg = *I;
     if (Dbg->getKind() == SDDbgValue::SDNODE) {