Index: llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
===================================================================
--- llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -73,6 +73,7 @@
     int JT;
     unsigned Align;    // CP alignment.
     unsigned char SymbolFlags;  // X86II::MO_*
+    bool NegateIndex = false;
 
     X86ISelAddressMode()
         : BaseType(RegBase), Base_FrameIndex(0), Scale(1), IndexReg(), Disp(0),
@@ -115,6 +116,8 @@
         dbgs() << " Base.FrameIndex " << Base_FrameIndex << '\n';
       dbgs() << " Scale " << Scale << '\n'
              << "IndexReg ";
+      if (NegateIndex)
+        dbgs() << "negate ";
       if (IndexReg.getNode())
         IndexReg.getNode()->dump(DAG);
       else
@@ -261,6 +264,7 @@
                                    SDValue &Base, SDValue &Scale,
                                    SDValue &Index, SDValue &Disp,
                                    SDValue &Segment) {
+      assert(!AM.NegateIndex && "Index should have been negated!");
       Base = (AM.BaseType == X86ISelAddressMode::FrameIndexBase)
                  ? CurDAG->getTargetFrameIndex(
                        AM.Base_FrameIndex,
@@ -1837,14 +1841,11 @@
     }
 
     // Ok, the transformation is legal and appears profitable. Go for it.
-    SDValue Zero = CurDAG->getConstant(0, dl, N.getValueType());
-    SDValue Neg = CurDAG->getNode(ISD::SUB, dl, N.getValueType(), Zero, RHS);
-    AM.IndexReg = Neg;
+    // Negation will be emitted later to avoid creating dangling nodes if this
+    // was an unprofitable LEA.
+    AM.IndexReg = RHS;
+    AM.NegateIndex = true;
     AM.Scale = 1;
-
-    // Insert the new nodes into the topological ordering.
-    insertDAGNode(*CurDAG, N, Zero);
-    insertDAGNode(*CurDAG, N, Neg);
     return false;
   }
 
@@ -2064,6 +2065,18 @@
   if (!AM.IndexReg.getNode())
     AM.IndexReg = CurDAG->getRegister(0, VT);
 
+  // Negate the index if needed.
+  if (AM.NegateIndex) {
+    SDLoc dl(N);
+    SDValue Zero = CurDAG->getConstant(0, dl, N.getValueType());
+    SDValue Neg = CurDAG->getNode(ISD::SUB, dl, N.getValueType(), Zero,
+                                  AM.IndexReg);
+    AM.IndexReg = Neg;
+    AM.NegateIndex = false;
+    insertDAGNode(*CurDAG, N, Zero);
+    insertDAGNode(*CurDAG, N, Neg);
+  }
+
   getAddressOperands(AM, SDLoc(N), Base, Scale, Index, Disp, Segment);
   return true;
 }
@@ -2283,6 +2296,18 @@
   if (Complexity <= 2)
     return false;
 
+  // Negate the index if needed.
+  if (AM.NegateIndex) {
+    SDLoc dl(N);
+    SDValue Zero = CurDAG->getConstant(0, dl, N.getValueType());
+    SDValue Neg = CurDAG->getNode(ISD::SUB, dl, N.getValueType(), Zero,
+                                  AM.IndexReg);
+    AM.IndexReg = Neg;
+    AM.NegateIndex = false;
+    insertDAGNode(*CurDAG, N, Zero);
+    insertDAGNode(*CurDAG, N, Neg);
+  }
+
   getAddressOperands(AM, DL, Base, Scale, Index, Disp, Segment);
   return true;
 }