Fix DIExpression::ExprOperand::appendToVector

appendToVector used the wrong overload of SmallVector::append, resulting
in it appending the same element to a vector `getSize()` times. This did
not cause a problem when initially committed because appendToVector was
only used to append 1-element operands.

This changes appendToVector to use the correct overload of append().

Testing: ./unittests/IR/IRTests --gtest_filter='*DIExpressionTest*'
llvm-svn: 336466
diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index 54062e2..db28d9a 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -834,9 +834,7 @@
         StackValue = false;
       }
     }
-    Ops.push_back(Op.getOp());
-    for (unsigned I = 0; I < Op.getNumArgs(); ++I)
-      Ops.push_back(Op.getArg(I));
+    Op.appendToVector(Ops);
   }
   if (StackValue)
     Ops.push_back(dwarf::DW_OP_stack_value);
@@ -906,9 +904,7 @@
         continue;
       }
       }
-      Ops.push_back(Op.getOp());
-      for (unsigned I = 0; I < Op.getNumArgs(); ++I)
-        Ops.push_back(Op.getArg(I));
+      Op.appendToVector(Ops);
     }
   }
   Ops.push_back(dwarf::DW_OP_LLVM_fragment);