[DAG, X86] Fix ISel-time node insertion ids

As in SystemZ backend, correctly propagate node ids when inserting new
unselected nodes into the DAG during instruction Seleciton for X86
target.

Fixes PR36865.

Reviewers: jyknight, craig.topper

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D44797

llvm-svn: 328233

1 files changed, 17 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 406e253fe4c..fcc1d8f4ed4 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -989,14 +989,29 @@ void SelectionDAGISel::EnforceNodeIdInvariant(SDNode *Node) {
     for (auto *U : N->uses()) {
       auto UId = U->getNodeId();
       if (UId > 0) {
-        int InvalidatedUId = -UId + 1;
-        U->setNodeId(InvalidatedUId);
+        InvalidateNodeId(U);
         Nodes.push_back(U);
       }
     }
   }
 }
 
+// InvalidateNodeId - As discusses in EnforceNodeIdInvariant, mark a
+// NodeId with the equivalent node id which is invalid for topological
+// pruning.
+void SelectionDAGISel::InvalidateNodeId(SDNode *N) {
+  int InvalidId = -N->getNodeId() + 1;
+  N->setNodeId(InvalidId);
+}
+
+// getUninvalidatedNodeId - get original uninvalidated node id.
+int SelectionDAGISel::getUninvalidatedNodeId(SDNode *N) {
+  int Id = N->getNodeId();
+  if (Id < 0)
+    return -Id + 1;
+  return Id;
+}
+
 void SelectionDAGISel::DoInstructionSelection() {
   DEBUG(dbgs() << "===== Instruction selection begins: "
                << printMBBReference(*FuncInfo->MBB) << " '"