diff --git a/build_tools/llvm_version.txt b/build_tools/llvm_version.txt
index 4c70951..3970ba8 100644
--- a/build_tools/llvm_version.txt
+++ b/build_tools/llvm_version.txt
@@ -1,2 +1,2 @@
-e75bc5c791e0e8dbe79f7453e55af9e8d03c9cc0
+f9dc2b7079350d0fed3bb3775f496b90483c9e42
 
diff --git a/tools/mlir-hlo-opt/mlir-hlo-opt.cpp b/tools/mlir-hlo-opt/mlir-hlo-opt.cpp
index c071e2c..f82c5cc 100644
--- a/tools/mlir-hlo-opt/mlir-hlo-opt.cpp
+++ b/tools/mlir-hlo-opt/mlir-hlo-opt.cpp
@@ -13,112 +13,18 @@ See the License for the specific language governing permissions and
 limitations under the License.
 ==============================================================================*/
 
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/InitLLVM.h"
-#include "llvm/Support/SourceMgr.h"
-#include "llvm/Support/ToolOutputFile.h"
 #include "mlir-hlo/Dialect/mhlo/IR/register.h"
 #include "mlir-hlo/Dialect/mhlo/transforms/register_passes.h"
-#include "mlir/IR/AsmState.h"
-#include "mlir/IR/Dialect.h"
-#include "mlir/IR/MLIRContext.h"
 #include "mlir/InitAllDialects.h"
 #include "mlir/InitAllPasses.h"
-#include "mlir/Pass/Pass.h"
-#include "mlir/Pass/PassManager.h"
-#include "mlir/Support/FileUtilities.h"
 #include "mlir/Support/MlirOptMain.h"
 
-// NOLINTNEXTLINE
-static llvm::cl::opt<std::string> inputFilename(llvm::cl::Positional,
-                                                llvm::cl::desc("<input file>"),
-                                                llvm::cl::init("-"));
-
-// NOLINTNEXTLINE
-static llvm::cl::opt<std::string> outputFilename(
-    "o", llvm::cl::desc("Output filename"), llvm::cl::value_desc("filename"),
-    llvm::cl::init("-"));
-
-// NOLINTNEXTLINE
-static llvm::cl::opt<bool> splitInputFile(
-    "split-input-file",
-    llvm::cl::desc("Split the input file into pieces and process each "
-                   "chunk independently"),
-    llvm::cl::init(false));
-
-// NOLINTNEXTLINE
-static llvm::cl::opt<bool> verifyDiagnostics(
-    "verify-diagnostics",
-    llvm::cl::desc("Check that emitted diagnostics match "
-                   "expected-* lines on the corresponding line"),
-    llvm::cl::init(false));
-
-// NOLINTNEXTLINE
-static llvm::cl::opt<bool> verifyPasses(
-    "verify-each",
-    llvm::cl::desc("Run the verifier after each transformation pass"),
-    llvm::cl::init(true));
-
-// NOLINTNEXTLINE
-static llvm::cl::opt<bool> allowUnregisteredDialects(
-    "allow-unregistered-dialect",
-    llvm::cl::desc("Allow operation with no registered dialects"),
-    llvm::cl::init(false));
-
-// NOLINTNEXTLINE
-static llvm::cl::opt<bool> showDialects(
-    "show-dialects", llvm::cl::desc("Print the list of registered dialects"),
-    llvm::cl::init(false));
-
 int main(int argc, char **argv) {
-  mlir::registerAllDialects();
+  mlir::DialectRegistry registry;
+  mlir::registerAllDialects(registry);
   mlir::registerAllPasses();
-
-  mlir::mhlo::registerAllDialects();
   mlir::mhlo::registerAllMhloPasses();
   mlir::lmhlo::registerAllLmhloPasses();
-
-  llvm::InitLLVM y(argc, argv);
-
-  // Register any pass manager command line options.
-  mlir::registerAsmPrinterCLOptions();
-  mlir::registerMLIRContextCLOptions();
-  mlir::registerPassManagerCLOptions();
-  mlir::PassPipelineCLParser passPipeline("", "Compiler passes to run");
-
-  // Parse pass names in main to ensure static initialization completed.
-  llvm::cl::ParseCommandLineOptions(argc, argv,
-                                    "MLIR modular optimizer driver\n");
-
-  if (showDialects) {
-    mlir::MLIRContext context;
-    llvm::outs() << "Registered Dialects:\n";
-    for (mlir::Dialect *dialect : context.getRegisteredDialects()) {
-      llvm::outs() << dialect->getNamespace() << "\n";
-    }
-    return 0;
-  }
-
-  // Set up the input file.
-  std::string errorMessage;
-  auto file = mlir::openInputFile(inputFilename, &errorMessage);
-  if (!file) {
-    llvm::errs() << errorMessage << "\n";
-    return 1;
-  }
-
-  auto output = mlir::openOutputFile(outputFilename, &errorMessage);
-  if (!output) {
-    llvm::errs() << errorMessage << "\n";
-    exit(1);
-  }
-
-  if (failed(MlirOptMain(output->os(), std::move(file), passPipeline,
-                         splitInputFile, verifyDiagnostics, verifyPasses,
-                         allowUnregisteredDialects))) {
-    return 1;
-  }
-  // Keep the output file if the invocation of MlirOptMain was successful.
-  output->keep();
-  return 0;
+  return failed(
+      mlir::MlirOptMain(argc, argv, "MLIR HLO pass driver\n", registry));
 }