Add support for undef

llvm-svn: 17055
diff --git a/llvm/lib/CodeGen/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter.cpp
index 11565df..eb57cce 100644
--- a/llvm/lib/CodeGen/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter.cpp
@@ -55,7 +55,7 @@
 // Print out the specified constant, without a storage class.  Only the
 // constants valid in constant expressions can occur here.
 void AsmPrinter::emitConstantValueOnly(const Constant *CV) {
-  if (CV->isNullValue())
+  if (CV->isNullValue() || isa<UndefValue>(CV))
     O << "0";
   else if (const ConstantBool *CB = dyn_cast<ConstantBool>(CV)) {
     assert(CB == ConstantBool::True);
@@ -171,7 +171,7 @@
 void AsmPrinter::emitGlobalConstant(const Constant *CV) {  
   const TargetData &TD = TM.getTargetData();
 
-  if (CV->isNullValue()) {
+  if (CV->isNullValue() || isa<UndefValue>(CV)) {
     emitZeros(TD.getTypeSize(CV->getType()));
     return;
   } else if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) {