Implement Promote for VAARG, and allow it to be custom promoted for people
who don't want the default behavior (Alpha).

llvm-svn: 25726
diff --git a/llvm/lib/Target/Alpha/AlphaISelLowering.cpp b/llvm/lib/Target/Alpha/AlphaISelLowering.cpp
index ac21b56..6779b90 100644
--- a/llvm/lib/Target/Alpha/AlphaISelLowering.cpp
+++ b/llvm/lib/Target/Alpha/AlphaISelLowering.cpp
@@ -141,6 +141,7 @@
   setOperationAction(ISD::VAEND,   MVT::Other, Expand);
   setOperationAction(ISD::VACOPY,  MVT::Other, Custom);
   setOperationAction(ISD::VAARG,   MVT::Other, Custom);
+  setOperationAction(ISD::VAARG,   MVT::i32,   Custom);
 
   setStackPointerRegisterToSaveRestore(Alpha::R30);
 
@@ -691,3 +692,13 @@
 
   return SDOperand();
 }
+
+SDOperand AlphaTargetLowering::CustomPromoteOperation(SDOperand Op, 
+                                                      SelectionDAG &DAG) {
+  assert(Op.getValueType() == MVT::i32 && 
+         Op.getOpcode() == ISD::VAARG &&
+         "Unknown node to custom promote!");
+  
+  // The code in LowerOperation already handles i32 vaarg
+  return LowerOperation(Op, DAG);
+}