message: NFC: Fix warning for uninitialized field.
diff: @@ -114,6 +114,8 @@ private:
  /// is the name of a pass, the InnerPipeline is empty, since passes cannot
  /// contain inner pipelines.
  struct PipelineElement {
  + PipelineElement(StringRef name) : name(name), registryEntry(nullptr) {}
  +
  StringRef name;
  const PassRegistryEntry *registryEntry;
  std::vector<PipelineElement> innerPipeline;
  @@ -178,7 +180,7 @@ LogicalResult TextualPipeline::parsePipelineText(StringRef text,
  for (;;) {
  std::vector<PipelineElement> &pipeline = *pipelineStack.back();
  size_t pos = text.find_first_of(",()");
  - pipeline.push_back({text.substr(0, pos).trim(), {}});
  + pipeline.emplace_back(/*name=*/text.substr(0, pos).trim());
  // If we have a single terminating name, we're done.
  if (pos == text.npos)
  