First part of bug 680:
Remove TLI.LowerVA* and replace it with SDNodes that are lowered the same
way as everything else.

llvm-svn: 25606
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 04b9de3..cc713cf5 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -169,7 +169,13 @@
   setOperationAction(ISD::DEBUG_LOC, MVT::Other, Expand);
   setOperationAction(ISD::DEBUG_LABEL, MVT::Other, Expand);
 
-  // Expand to the default code.
+  // VASTART needs to be custom lowered to use the VarArgsFrameIndex
+  setOperationAction(ISD::VASTART           , MVT::Other, Custom);
+  
+  // Use the default implementation.
+  setOperationAction(ISD::VAARG             , MVT::Other, Expand);
+  setOperationAction(ISD::VACOPY            , MVT::Other, Expand);
+  setOperationAction(ISD::VAEND             , MVT::Other, Expand);
   setOperationAction(ISD::STACKSAVE,          MVT::Other, Expand); 
   setOperationAction(ISD::STACKRESTORE,       MVT::Other, Expand);
   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32  , Expand);
@@ -641,40 +647,6 @@
   }
 }
 
-SDOperand
-X86TargetLowering::LowerVAStart(SDOperand Chain, SDOperand VAListP,
-                                Value *VAListV, SelectionDAG &DAG) {
-  // vastart just stores the address of the VarArgsFrameIndex slot.
-  SDOperand FR = DAG.getFrameIndex(VarArgsFrameIndex, MVT::i32);
-  return DAG.getNode(ISD::STORE, MVT::Other, Chain, FR, VAListP,
-                     DAG.getSrcValue(VAListV));
-}
-
-
-std::pair<SDOperand,SDOperand>
-X86TargetLowering::LowerVAArg(SDOperand Chain, SDOperand VAListP,
-                              Value *VAListV, const Type *ArgTy,
-                              SelectionDAG &DAG) {
-  MVT::ValueType ArgVT = getValueType(ArgTy);
-  SDOperand Val = DAG.getLoad(MVT::i32, Chain,
-                              VAListP, DAG.getSrcValue(VAListV));
-  SDOperand Result = DAG.getLoad(ArgVT, Chain, Val,
-                                 DAG.getSrcValue(NULL));
-  unsigned Amt;
-  if (ArgVT == MVT::i32)
-    Amt = 4;
-  else {
-    assert((ArgVT == MVT::i64 || ArgVT == MVT::f64) &&
-           "Other types should have been promoted for varargs!");
-    Amt = 8;
-  }
-  Val = DAG.getNode(ISD::ADD, Val.getValueType(), Val,
-                    DAG.getConstant(Amt, Val.getValueType()));
-  Chain = DAG.getNode(ISD::STORE, MVT::Other, Chain,
-                      Val, VAListP, DAG.getSrcValue(VAListV));
-  return std::make_pair(Result, Chain);
-}
-
 //===----------------------------------------------------------------------===//
 //                    Fast Calling Convention implementation
 //===----------------------------------------------------------------------===//
@@ -1898,6 +1870,14 @@
                            DAG.getSrcValue(NULL));
     return Result;
   }
+  case ISD::VASTART: {
+    // vastart just stores the address of the VarArgsFrameIndex slot into the
+    // memory location argument.
+    // FIXME: Replace MVT::i32 with PointerTy
+    SDOperand FR = DAG.getFrameIndex(VarArgsFrameIndex, MVT::i32);
+    return DAG.getNode(ISD::STORE, MVT::Other, Op.getOperand(0), FR, 
+                       Op.getOperand(1), Op.getOperand(2));
+  }
   }
 }