Fold single use token factor nodes into other token factor nodes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19701 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 2 deletions

diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 2994d4812b..b557892b3b 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -264,8 +264,16 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
     std::vector<SDOperand> Ops;
     bool Changed = false;
     for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) {
-      Ops.push_back(LegalizeOp(Node->getOperand(i)));  // Legalize the operands
-      Changed |= Ops[i] != Node->getOperand(i);
+      SDOperand Op = Node->getOperand(i);
+      // Fold single-use TokenFactor nodes into this token factor as we go.
+      if (Op.getOpcode() == ISD::TokenFactor && Op.hasOneUse()) {
+        Changed = true;
+        for (unsigned j = 0, e = Op.getNumOperands(); j != e; ++j)
+          Ops.push_back(LegalizeOp(Op.getOperand(j)));
+      } else {
+        Ops.push_back(LegalizeOp(Op));  // Legalize the operands
+        Changed |= Ops[i] != Op;
+      }
     }
     if (Changed)
       Result = DAG.getNode(ISD::TokenFactor, MVT::Other, Ops);