Index: lib/Target/X86/X86ISelDAGToDAG.cpp
===================================================================
--- lib/Target/X86/X86ISelDAGToDAG.cpp
+++ lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -2638,6 +2638,51 @@
     }
     break;
   }
+
+  case ISD::ZERO_EXTEND: {
+    if (NVT != MVT::i32)
+      break;
+
+    SDValue N0 = Node->getOperand(0);
+    if (N0->getOpcode() != X86ISD::SETCC)
+      break;
+
+    SDValue N01 = N0->getOperand(1);
+
+    // 0 = xor r,r.  This clobbers EFLAGS; let the scheduler figure that out.
+    SDValue Zero = SDValue(CurDAG->getMachineNode(X86::MOV32r0, dl, NVT), 0);
+
+    // Select the things below us, if they haven't been selected already.
+    Select(N01.getNode());
+
+    // Copy the flags out whatever's below us.  Produce a glue.
+    SDValue Flags =
+        CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, X86::EFLAGS,
+                             N01, /*Glue=*/SDValue());
+
+    // Pick a SETCC opcode.
+    unsigned SetCCOpc =
+        X86::getSETFromCond((X86::CondCode)N0->getConstantOperandVal(0));
+
+    // Now we can select our node; make abundant use of glue.
+    SDNode *SetCC = CurDAG->getMachineNode(SetCCOpc, SDLoc(N0), MVT::i8,
+                                           MVT::Glue, Flags.getValue(1));
+
+    // And insert it into the zero reg, gluing again.
+    SDNode *NewNode = CurDAG->getMachineNode(
+        X86::INSERT_SUBREG, dl, MVT::i32,
+        {Zero, N0, CurDAG->getTargetConstant(X86::sub_8bit, dl, MVT::i32),
+         SDValue(SetCC, 1)});
+
+    ReplaceUses(N0, SDValue(SetCC, 0));
+    ReplaceUses(SDValue(Node, 0), SDValue(NewNode, 0));
+
+    CurDAG->RemoveDeadNode(N0.getNode());
+    CurDAG->RemoveDeadNode(Node);
+    return;
+  }
+
+
   case ISD::STORE: {
     // Change a chain of {load; incr or dec; store} of the same value into
     // a simple increment or decrement through memory of that value, if the