[SDAG] Deal with deleted node in PromoteIntShiftOp

Deal with case that initial node is deleted during dag-combine leading
to an assertional failure in promoteIntShiftOp.

Fixes PR32420.

Reviewers: spatel, RKSimon

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D31403

llvm-svn: 298931

1 files changed, 11 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 5d37c5cb400..2cd70ed19fa 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1144,26 +1144,32 @@ SDValue DAGCombiner::PromoteIntShiftOp(SDValue Op) {
   if (TLI.IsDesirableToPromoteOp(Op, PVT)) {
     assert(PVT != VT && "Don't know what type to promote to!");
 
+    DEBUG(dbgs() << "\nPromoting "; Op.getNode()->dump(&DAG));
+
     bool Replace = false;
     SDValue N0 = Op.getOperand(0);
+    SDValue N1 = Op.getOperand(1);
     if (Opc == ISD::SRA)
       N0 = SExtPromoteOperand(N0, PVT);
     else if (Opc == ISD::SRL)
       N0 = ZExtPromoteOperand(N0, PVT);
     else
       N0 = PromoteOperand(N0, PVT, Replace);
+
     if (!N0.getNode())
       return SDValue();
 
+    SDLoc DL(Op);
+    SDValue RV =
+        DAG.getNode(ISD::TRUNCATE, DL, VT, DAG.getNode(Opc, DL, PVT, N0, N1));
+
     AddToWorklist(N0.getNode());
     if (Replace)
       ReplaceLoadWithPromotedLoad(Op.getOperand(0).getNode(), N0.getNode());
 
-    DEBUG(dbgs() << "\nPromoting ";
-          Op.getNode()->dump(&DAG));
-    SDLoc DL(Op);
-    return DAG.getNode(ISD::TRUNCATE, DL, VT,
-                       DAG.getNode(Opc, DL, PVT, N0, Op.getOperand(1)));
+    // Deal with Op being deleted.
+    if (Op && Op.getOpcode() != ISD::DELETED_NODE)
+      return RV;
   }
   return SDValue();
 }