Index: include/llvm/CodeGen/CallingConvLower.h
===================================================================
--- include/llvm/CodeGen/CallingConvLower.h
+++ include/llvm/CodeGen/CallingConvLower.h
@@ -260,6 +260,10 @@
     Locs.push_back(V);
   }
 
+  CCValAssign lastLoc(void) {
+    return Locs.back();
+  }
+
   LLVMContext &getContext() const { return Context; }
   MachineFunction &getMachineFunction() const { return MF; }
   CallingConv::ID getCallingConv() const { return CallingConv; }
Index: include/llvm/Target/TargetCallingConv.h
===================================================================
--- include/llvm/Target/TargetCallingConv.h
+++ include/llvm/Target/TargetCallingConv.h
@@ -48,6 +48,7 @@
     unsigned IsCopyElisionCandidate : 1; ///< Argument copy elision candidate
 
     unsigned ByValSize; ///< Byval struct size
+    EVT OrigVt; ///< Original value type before split
 
   public:
     ArgFlagsTy()
@@ -57,7 +58,8 @@
           IsSecArgPass(0), ByValAlign(0), OrigAlign(0),
           IsInConsecutiveRegsLast(0), IsInConsecutiveRegs(0),
           IsCopyElisionCandidate(0), ByValSize(0) {
-      static_assert(sizeof(*this) == 2 * sizeof(unsigned), "flags are too big");
+      static_assert(sizeof(*this) == 2 * sizeof(unsigned) + sizeof(EVT),
+                    "flags are too big");
     }
 
     bool isZExt() const { return IsZExt; }
@@ -128,6 +130,9 @@
 
     unsigned getByValSize() const { return ByValSize; }
     void setByValSize(unsigned S) { ByValSize = S; }
+
+    EVT getOrigVt() const { return OrigVt; }
+    void setOrigVt(EVT Vt) { OrigVt = Vt; }
   };
 
   /// InputArg - This struct carries flags and type information about a
Index: include/llvm/Target/TargetCallingConv.td
===================================================================
--- include/llvm/Target/TargetCallingConv.td
+++ include/llvm/Target/TargetCallingConv.td
@@ -32,6 +32,12 @@
   list<ValueType> VTs = vts;
 }
 
+/// CCIfSplitFrom - If the current argument is splited from one of the specified
+/// types, apply Action A.
+class CCIfSplitFrom<list<ValueType> vts, CCAction A> : CCPredicateAction<A> {
+  list<ValueType> VTs = vts;
+}
+
 /// CCIf - If the predicate matches, apply A.
 class CCIf<string predicate, CCAction A> : CCPredicateAction<A> {
   string Predicate = predicate;
@@ -150,6 +156,12 @@
   ValueType DestTy = destTy;
 }
 
+/// CCPassIndirectBySamePointer - Just like CCPassIndirect except pass by the
+/// same pointer.
+class CCPassIndirectBySamePointer<ValueType destTy> : CCAction {
+  ValueType DestTy = destTy;
+}
+
 /// CCDelegateTo - This action invokes the specified sub-calling-convention.  It
 /// is successful if the specified CC matches.
 class CCDelegateTo<CallingConv cc> : CCAction {
Index: lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -8245,6 +8245,7 @@
             MyFlags.Flags.setSplitEnd();
         }
 
+        MyFlags.Flags.setOrigVt(VT);
         CLI.Outs.push_back(MyFlags);
         CLI.OutVals.push_back(Parts[j]);
       }
@@ -8701,6 +8702,7 @@
           if (i == NumRegs - 1)
             MyFlags.Flags.setSplitEnd();
         }
+        MyFlags.Flags.setOrigVt(VT);
         Ins.push_back(MyFlags);
       }
       if (NeedsRegBlock && Value == NumValues - 1)
Index: utils/TableGen/CallingConvEmitter.cpp
===================================================================
--- utils/TableGen/CallingConvEmitter.cpp
+++ utils/TableGen/CallingConvEmitter.cpp
@@ -92,7 +92,13 @@
         if (i != 0) O << " ||\n    " << IndentStr;
         O << "LocVT == " << getEnumName(getValueType(VT));
       }
-
+    } else if (Action->isSubClassOf("CCIfSplitFrom")) {
+      ListInit *VTs = Action->getValueAsListInit("VTs");
+      for (unsigned i = 0, e = VTs->size(); i != e; ++i) {
+        Record *VT = VTs->getElementAsRecord(i);
+        if (i != 0) O << " ||\n    " << IndentStr;
+        O << "ArgFlags.getOrigVt() == " << getEnumName(getValueType(VT));
+      }
     } else if (Action->isSubClassOf("CCIf")) {
       O << Action->getValueAsString("Predicate");
     } else {
@@ -251,6 +257,14 @@
       Record *DestTy = Action->getValueAsDef("DestTy");
       O << IndentStr << "LocVT = " << getEnumName(getValueType(DestTy)) <<";\n";
       O << IndentStr << "LocInfo = CCValAssign::BCvt;\n";
+    } else if (Action->isSubClassOf("CCPassIndirectBySamePointer")) {
+      Record *DestTy = Action->getValueAsDef("DestTy");
+      O << IndentStr << "LocVT = " << getEnumName(getValueType(DestTy)) <<";\n";
+      O << IndentStr << "LocInfo = CCValAssign::Indirect;\n";
+      O << IndentStr << "if (!ArgFlags.isSplit()) {\n"
+        << IndentStr << IndentStr << "State.addLoc(State.lastLoc());\n"
+        << IndentStr << IndentStr << "return false;\n"
+        << IndentStr << "}\n";
     } else if (Action->isSubClassOf("CCPassIndirect")) {
       Record *DestTy = Action->getValueAsDef("DestTy");
       O << IndentStr << "LocVT = " << getEnumName(getValueType(DestTy)) <<";\n";