Paper over CBackend/2004-08-09-va-end-null.ll

Note that this indicates a serious problem with the way we are emitting varargs,
but this should not be properly fixed until after 1.3.

This patch SHOULD go into 1.3.

llvm-svn: 15602

llvm/lib/Target/CBackend/Writer.cpp

@@ -1390,9 +1390,13 @@ void CWriter::visitCallInst(CallInst &I) {
         Out << ")";
         return;
       case Intrinsic::vaend:
+        if (!isa<ConstantPointerNull>(I.getOperand(1))) {
           Out << "va_end(*(va_list*)&";
           writeOperand(I.getOperand(1));
           Out << ")";
+        } else {
+          Out << "va_end(*(va_list*)0)";
+        }
         return;
       case Intrinsic::vacopy:
         Out << "0;";