fix a tblgen bug that Evan ran into, where we would lose the '$src' name
on patterns like "(set R32:$dst, (i32 imm:$src))"


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24383 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/DAGISelEmitter.cpp b/utils/TableGen/DAGISelEmitter.cpp
index 5cc1f27..092fff8 100644
--- a/utils/TableGen/DAGISelEmitter.cpp
+++ b/utils/TableGen/DAGISelEmitter.cpp
@@ -631,9 +631,7 @@
       if (R->isSubClassOf("SDNode") || R->isSubClassOf("PatFrag")) {
         Dag->setArg(0, new DagInit(R,
                                 std::vector<std::pair<Init*, std::string> >()));
-        TreePatternNode *TPN = ParseTreePattern(Dag);
-        TPN->setName(Dag->getArgName(0));
-        return TPN;
+        return ParseTreePattern(Dag);
       }   
       
       New = new TreePatternNode(DI);
@@ -651,6 +649,7 @@
     
     // Apply the type cast.
     New->UpdateNodeType(getValueType(Operator), *this);
+    New->setName(Dag->getArgName(0));
     return New;
   }
   
@@ -672,7 +671,8 @@
     Init *Arg = Dag->getArg(i);
     if (DagInit *DI = dynamic_cast<DagInit*>(Arg)) {
       Children.push_back(ParseTreePattern(DI));
-      Children.back()->setName(Dag->getArgName(i));
+      if (Children.back()->getName().empty())
+        Children.back()->setName(Dag->getArgName(i));
     } else if (DefInit *DefI = dynamic_cast<DefInit*>(Arg)) {
       Record *R = DefI->getDef();
       // Direct reference to a leaf DagNode or PatFrag?  Turn it into a