diff --git a/mlir/include/mlir/Dialect/CMakeLists.txt b/mlir/include/mlir/Dialect/CMakeLists.txt
--- a/mlir/include/mlir/Dialect/CMakeLists.txt
+++ b/mlir/include/mlir/Dialect/CMakeLists.txt
@@ -1,6 +1,6 @@
+add_subdirectory(Affine)
 add_subdirectory(AMDGPU)
 add_subdirectory(AMX)
-add_subdirectory(Affine)
 add_subdirectory(Arith)
 add_subdirectory(ArmNeon)
 add_subdirectory(ArmSME)
@@ -15,11 +15,11 @@
 add_subdirectory(GPU)
 add_subdirectory(Index)
 add_subdirectory(IRDL)
-add_subdirectory(LLVMIR)
 add_subdirectory(Linalg)
-add_subdirectory(MLProgram)
+add_subdirectory(LLVMIR)
 add_subdirectory(Math)
 add_subdirectory(MemRef)
+add_subdirectory(MLProgram)
 add_subdirectory(NVGPU)
 add_subdirectory(OpenACC)
 add_subdirectory(OpenMP)
@@ -27,12 +27,13 @@
 add_subdirectory(PDLInterp)
 add_subdirectory(Quant)
 add_subdirectory(SCF)
-add_subdirectory(SPIRV)
 add_subdirectory(Shape)
 add_subdirectory(SparseTensor)
+add_subdirectory(SPIRV)
 add_subdirectory(Tensor)
 add_subdirectory(Tosa)
 add_subdirectory(Transform)
+add_subdirectory(Ub)
 add_subdirectory(Utils)
 add_subdirectory(Vector)
 add_subdirectory(X86Vector)
diff --git a/mlir/include/mlir/Dialect/Ub/CMakeLists.txt b/mlir/include/mlir/Dialect/Ub/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/mlir/include/mlir/Dialect/Ub/CMakeLists.txt
@@ -0,0 +1 @@
+add_subdirectory(IR)
diff --git a/mlir/include/mlir/Dialect/Ub/IR/CMakeLists.txt b/mlir/include/mlir/Dialect/Ub/IR/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/mlir/include/mlir/Dialect/Ub/IR/CMakeLists.txt
@@ -0,0 +1,8 @@
+set(LLVM_TARGET_DEFINITIONS UbOps.td)
+mlir_tablegen(UbOps.h.inc -gen-op-decls)
+mlir_tablegen(UbOps.cpp.inc -gen-op-defs)
+mlir_tablegen(UbOpsDialect.h.inc -gen-dialect-decls)
+mlir_tablegen(UbOpsDialect.cpp.inc -gen-dialect-defs)
+add_public_tablegen_target(MLIRUbOpsIncGen)
+
+add_mlir_doc(FuncOps UbOps Dialects/ -gen-op-doc)
diff --git a/mlir/include/mlir/Dialect/Ub/IR/UbOps.h b/mlir/include/mlir/Dialect/Ub/IR/UbOps.h
new file mode 100644
--- /dev/null
+++ b/mlir/include/mlir/Dialect/Ub/IR/UbOps.h
@@ -0,0 +1,21 @@
+//===- FuncOps.h - Ub Dialect Operations ----------------------*--- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_DIALECT_UB_IR_OPS_H
+#define MLIR_DIALECT_UB_IR_OPS_H
+
+#include "mlir/IR/Dialect.h"
+#include "mlir/IR/OpImplementation.h"
+#include "mlir/Interfaces/SideEffectInterfaces.h"
+
+#define GET_OP_CLASSES
+#include "mlir/Dialect/Ub/IR/UbOps.h.inc"
+
+#include "mlir/Dialect/Ub/IR/UbOpsDialect.h.inc"
+
+#endif // MLIR_DIALECT_UB_IR_OPS_H
diff --git a/mlir/include/mlir/Dialect/Ub/IR/UbOps.td b/mlir/include/mlir/Dialect/Ub/IR/UbOps.td
new file mode 100644
--- /dev/null
+++ b/mlir/include/mlir/Dialect/Ub/IR/UbOps.td
@@ -0,0 +1,40 @@
+//===- FuncOps.td - Ub operation definitions ---------------*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_DIALECT_UB_IR_UBOPS_TD
+#define MLIR_DIALECT_UB_IR_UBOPS_TD
+
+include "mlir/Interfaces/SideEffectInterfaces.td"
+
+def Ub_Dialect : Dialect {
+  let name = "ub";
+  let cppNamespace = "::mlir::ub";
+}
+
+// Base class for Func dialect ops.
+class Ub_Op<string mnemonic, list<Trait> traits = []> :
+    Op<Ub_Dialect, mnemonic, traits>;
+
+//===----------------------------------------------------------------------===//
+// PoisonOp
+//===----------------------------------------------------------------------===//
+
+def PoisonOp : Ub_Op<"poison", [Pure]> {
+  let summary = "A poison value is a result of an erroneous operation.";
+  let description = [{
+    In order to facilitate speculative execution, many instructions do not
+    invoke immediate undefined behavior when provided with illegal operands,
+    and return a poison value instead.
+  }];
+
+  let results = (outs AnyType:$result);
+
+  let assemblyFormat = "attr-dict `:` type($result)";
+}
+
+#endif // MLIR_DIALECT_UB_IR_UBOPS_TD
diff --git a/mlir/include/mlir/InitAllDialects.h b/mlir/include/mlir/InitAllDialects.h
--- a/mlir/include/mlir/InitAllDialects.h
+++ b/mlir/include/mlir/InitAllDialects.h
@@ -79,6 +79,7 @@
 #include "mlir/Dialect/Tosa/IR/TosaOps.h"
 #include "mlir/Dialect/Transform/IR/TransformDialect.h"
 #include "mlir/Dialect/Transform/PDLExtension/PDLExtension.h"
+#include "mlir/Dialect/Ub/IR/UbOps.h"
 #include "mlir/Dialect/Vector/IR/VectorOps.h"
 #include "mlir/Dialect/Vector/TransformOps/VectorTransformOps.h"
 #include "mlir/Dialect/Vector/Transforms/BufferizableOpInterfaceImpl.h"
@@ -93,10 +94,12 @@
   // clang-format off
   registry.insert<acc::OpenACCDialect,
                   affine::AffineDialect,
-                  arith::ArithDialect,
                   amdgpu::AMDGPUDialect,
                   amx::AMXDialect,
+                  arith::ArithDialect,
                   arm_neon::ArmNeonDialect,
+                  arm_sme::ArmSMEDialect,
+                  arm_sve::ArmSVEDialect,
                   async::AsyncDialect,
                   bufferization::BufferizationDialect,
                   cf::ControlFlowDialect,
@@ -107,28 +110,27 @@
                   gpu::GPUDialect,
                   index::IndexDialect,
                   irdl::IRDLDialect,
-                  LLVM::LLVMDialect,
                   linalg::LinalgDialect,
+                  LLVM::LLVMDialect,
                   math::MathDialect,
                   memref::MemRefDialect,
                   ml_program::MLProgramDialect,
                   nvgpu::NVGPUDialect,
-                  scf::SCFDialect,
+                  NVVM::NVVMDialect,
                   omp::OpenMPDialect,
                   pdl::PDLDialect,
                   pdl_interp::PDLInterpDialect,
                   quant::QuantizationDialect,
-                  spirv::SPIRVDialect,
-                  arm_sme::ArmSMEDialect,
-                  arm_sve::ArmSVEDialect,
-                  vector::VectorDialect,
-                  NVVM::NVVMDialect,
                   ROCDL::ROCDLDialect,
+                  scf::SCFDialect,
                   shape::ShapeDialect,
                   sparse_tensor::SparseTensorDialect,
+                  spirv::SPIRVDialect,
                   tensor::TensorDialect,
-                  transform::TransformDialect,
                   tosa::TosaDialect,
+                  transform::TransformDialect,
+                  ub::UbDialect,
+                  vector::VectorDialect,
                   x86vector::X86VectorDialect>();
   // clang-format on
 
diff --git a/mlir/lib/Dialect/CMakeLists.txt b/mlir/lib/Dialect/CMakeLists.txt
--- a/mlir/lib/Dialect/CMakeLists.txt
+++ b/mlir/lib/Dialect/CMakeLists.txt
@@ -1,11 +1,11 @@
 add_subdirectory(Affine)
 add_subdirectory(AMDGPU)
+add_subdirectory(AMX)
 add_subdirectory(Arith)
 add_subdirectory(ArmNeon)
 add_subdirectory(ArmSME)
 add_subdirectory(ArmSVE)
 add_subdirectory(Async)
-add_subdirectory(AMX)
 add_subdirectory(Bufferization)
 add_subdirectory(Complex)
 add_subdirectory(ControlFlow)
@@ -33,6 +33,7 @@
 add_subdirectory(Tensor)
 add_subdirectory(Tosa)
 add_subdirectory(Transform)
+add_subdirectory(Ub)
 add_subdirectory(Utils)
 add_subdirectory(Vector)
 add_subdirectory(X86Vector)
diff --git a/mlir/lib/Dialect/Ub/CMakeLists.txt b/mlir/lib/Dialect/Ub/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/mlir/lib/Dialect/Ub/CMakeLists.txt
@@ -0,0 +1 @@
+add_subdirectory(IR)
diff --git a/mlir/lib/Dialect/Ub/IR/CMakeLists.txt b/mlir/lib/Dialect/Ub/IR/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/mlir/lib/Dialect/Ub/IR/CMakeLists.txt
@@ -0,0 +1,12 @@
+add_mlir_dialect_library(MLIRUbDialect
+  UbOps.cpp
+
+  ADDITIONAL_HEADER_DIRS
+  ${MLIR_MAIN_INCLUDE_DIR}/mlir/Dialect/Ub
+
+  DEPENDS
+  MLIRUbOpsIncGen
+
+  LINK_LIBS PUBLIC
+  MLIRIR
+  )
diff --git a/mlir/lib/Dialect/Ub/IR/UbOps.cpp b/mlir/lib/Dialect/Ub/IR/UbOps.cpp
new file mode 100644
--- /dev/null
+++ b/mlir/lib/Dialect/Ub/IR/UbOps.cpp
@@ -0,0 +1,28 @@
+//===- FuncOps.cpp - Ub Dialect Operations --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Ub/IR/UbOps.h"
+
+#include "mlir/Dialect/Ub/IR/UbOpsDialect.cpp.inc"
+
+using namespace mlir;
+using namespace mlir::ub;
+
+//===----------------------------------------------------------------------===//
+// UbDialect
+//===----------------------------------------------------------------------===//
+
+void UbDialect::initialize() {
+  addOperations<
+#define GET_OP_LIST
+#include "mlir/Dialect/Ub/IR/UbOps.cpp.inc"
+      >();
+}
+
+#define GET_OP_CLASSES
+#include "mlir/Dialect/Ub/IR/UbOps.cpp.inc"
diff --git a/mlir/test/Dialect/Ub/ops.mlir b/mlir/test/Dialect/Ub/ops.mlir
new file mode 100644
--- /dev/null
+++ b/mlir/test/Dialect/Ub/ops.mlir
@@ -0,0 +1,12 @@
+// RUN: mlir-opt %s | FileCheck %s
+// Verify the printed output can be parsed.
+// RUN: mlir-opt %s | mlir-opt | FileCheck %s
+// Verify the generic form can be parsed.
+// RUN: mlir-opt -mlir-print-op-generic %s | mlir-opt | FileCheck %s
+
+// CHECK-LABEL: func @poison()
+//       CHECK:   %{{.*}} = ub.poison : i32
+func.func @poison() -> i32 {
+  %0 = ub.poison : i32
+  return %0 : i32
+}