SDAG: Have SelectNodeTo replace uses if it CSE's instead of morphing a node

It's awkward to force callers of SelectNodeTo to figure out whether
the node was morphed or CSE'd. Update uses here instead of requiring
callers to (sometimes) do it.

llvm-svn: 269235

2 files changed, 8 insertions, 9 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 5a61708b651..f2a38d7a3af 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -5942,10 +5942,14 @@ SDNode *SelectionDAG::SelectNodeTo(SDNode *N, unsigned MachineOpc,
 
 SDNode *SelectionDAG::SelectNodeTo(SDNode *N, unsigned MachineOpc,
                                    SDVTList VTs,ArrayRef<SDValue> Ops) {
-  N = MorphNodeTo(N, ~MachineOpc, VTs, Ops);
+  SDNode *New = MorphNodeTo(N, ~MachineOpc, VTs, Ops);
   // Reset the NodeID to -1.
-  N->setNodeId(-1);
-  return N;
+  New->setNodeId(-1);
+  if (New != N) {
+    ReplaceAllUsesWith(N, New);
+    RemoveDeadNode(N);
+  }
+  return New;
 }
 
 /// UpdadeSDLocOnMergedSDNode - If the opt level is -O0 then it throws away
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 6bb5060f5bb..9a0fd6fba6c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -2127,12 +2127,7 @@ void SelectionDAGISel::Select_WRITE_REGISTER(SDNode *Op) {
 }
 
 void SelectionDAGISel::Select_UNDEF(SDNode *N) {
-  SDNode *New =
-      CurDAG->SelectNodeTo(N, TargetOpcode::IMPLICIT_DEF, N->getValueType(0));
-  if (New != N) {
-    ReplaceUses(N, New);
-    CurDAG->RemoveDeadNode(N);
-  }
+  CurDAG->SelectNodeTo(N, TargetOpcode::IMPLICIT_DEF, N->getValueType(0));
 }
 
 /// GetVBR - decode a vbr encoding whose top bit is set.