diff --git a/mlir/docs/Tutorials/Toy/Ch-6.md b/mlir/docs/Tutorials/Toy/Ch-6.md
--- a/mlir/docs/Tutorials/Toy/Ch-6.md
+++ b/mlir/docs/Tutorials/Toy/Ch-6.md
@@ -63,7 +63,7 @@
 ```c++
   mlir::ConversionTarget target(getContext());
   target.addLegalDialect<mlir::LLVMDialect>();
-  target.addLegalOp<mlir::ModuleOp, mlir::ModuleTerminatorOp>();
+  target.addLegalOp<mlir::ModuleOp>();
 ```
 
 ### Type Converter
diff --git a/mlir/docs/Tutorials/UnderstandingTheIRStructure.md b/mlir/docs/Tutorials/UnderstandingTheIRStructure.md
--- a/mlir/docs/Tutorials/UnderstandingTheIRStructure.md
+++ b/mlir/docs/Tutorials/UnderstandingTheIRStructure.md
@@ -110,7 +110,6 @@
     "dialect.innerop6"() : () -> ()
     "dialect.innerop7"() : () -> ()
   }) {"other attribute" = 42 : i64} : () -> ()
-  "module_terminator"() : () -> ()
 }) : () -> ()
 ```
 
@@ -147,7 +146,6 @@
              0 nested regions:
             visiting op: 'dialect.innerop7' with 0 operands and 0 results
              0 nested regions:
-      visiting op: 'module_terminator' with 0 operands and 0 results
        0 nested regions:
 ```
 
diff --git a/mlir/examples/toy/Ch6/mlir/LowerToLLVM.cpp b/mlir/examples/toy/Ch6/mlir/LowerToLLVM.cpp
--- a/mlir/examples/toy/Ch6/mlir/LowerToLLVM.cpp
+++ b/mlir/examples/toy/Ch6/mlir/LowerToLLVM.cpp
@@ -174,7 +174,7 @@
   // final target for this lowering. For this lowering, we are only targeting
   // the LLVM dialect.
   LLVMConversionTarget target(getContext());
-  target.addLegalOp<ModuleOp, ModuleTerminatorOp>();
+  target.addLegalOp<ModuleOp>();
 
   // During this lowering, we will also be lowering the MemRef types, that are
   // currently being operated on, to a representation in LLVM. To perform this
diff --git a/mlir/examples/toy/Ch7/mlir/LowerToLLVM.cpp b/mlir/examples/toy/Ch7/mlir/LowerToLLVM.cpp
--- a/mlir/examples/toy/Ch7/mlir/LowerToLLVM.cpp
+++ b/mlir/examples/toy/Ch7/mlir/LowerToLLVM.cpp
@@ -174,7 +174,7 @@
   // final target for this lowering. For this lowering, we are only targeting
   // the LLVM dialect.
   LLVMConversionTarget target(getContext());
-  target.addLegalOp<ModuleOp, ModuleTerminatorOp>();
+  target.addLegalOp<ModuleOp>();
 
   // During this lowering, we will also be lowering the MemRef types, that are
   // currently being operated on, to a representation in LLVM. To perform this
diff --git a/mlir/include/mlir/IR/Block.h b/mlir/include/mlir/IR/Block.h
--- a/mlir/include/mlir/IR/Block.h
+++ b/mlir/include/mlir/IR/Block.h
@@ -226,6 +226,14 @@
   /// Returns true if this blocks has no successors.
   bool hasNoSuccessors() { return succ_begin() == succ_end(); }
 
+  /// Returns true if this block may be valid without terminator. That is if:
+  /// - it does not have a parent region.
+  /// - Or the parent region have a single block and:
+  ///    - This region does not have a parent op.
+  ///    - Or the parent op is unregistered.
+  ///    - Or the parent op has the NoTerminator trait.
+  bool mayNotHaveTerminator();
+
   /// If this block has exactly one predecessor, return it.  Otherwise, return
   /// null.
   ///
diff --git a/mlir/include/mlir/IR/BuiltinOps.h b/mlir/include/mlir/IR/BuiltinOps.h
--- a/mlir/include/mlir/IR/BuiltinOps.h
+++ b/mlir/include/mlir/IR/BuiltinOps.h
@@ -15,6 +15,7 @@
 
 #include "mlir/IR/FunctionSupport.h"
 #include "mlir/IR/OwningOpRef.h"
+#include "mlir/IR/RegionKindInterface.h"
 #include "mlir/IR/SymbolTable.h"
 #include "mlir/Interfaces/CallInterfaces.h"
 #include "mlir/Interfaces/CastInterfaces.h"
diff --git a/mlir/include/mlir/IR/BuiltinOps.td b/mlir/include/mlir/IR/BuiltinOps.td
--- a/mlir/include/mlir/IR/BuiltinOps.td
+++ b/mlir/include/mlir/IR/BuiltinOps.td
@@ -15,6 +15,7 @@
 #define BUILTIN_OPS
 
 include "mlir/IR/BuiltinDialect.td"
+include "mlir/IR/RegionKindInterface.td"
 include "mlir/IR/SymbolInterfaces.td"
 include "mlir/Interfaces/CallInterfaces.td"
 include "mlir/Interfaces/CastInterfaces.td"
@@ -158,9 +159,8 @@
 //===----------------------------------------------------------------------===//
 
 def ModuleOp : Builtin_Op<"module", [
-  AffineScope, IsolatedFromAbove, NoRegionArguments, SymbolTable, Symbol,
-  SingleBlockImplicitTerminator<"ModuleTerminatorOp">
-]> {
+  AffineScope, IsolatedFromAbove, NoRegionArguments, SymbolTable, Symbol] 
+  # NoTerminator.traits> {
   let summary = "A top level container operation";
   let description = [{
     A `module` represents a top-level container operation. It contains a single
@@ -206,22 +206,6 @@
   let skipDefaultBuilders = 1;
 }
 
-//===----------------------------------------------------------------------===//
-// ModuleTerminatorOp
-//===----------------------------------------------------------------------===//
-
-def ModuleTerminatorOp : Builtin_Op<"module_terminator", [
-  Terminator, HasParent<"ModuleOp">
-]> {
-  let summary = "A pseudo op that marks the end of a module";
-  let description = [{
-    `module_terminator` is a special terminator operation for the body of a
-    `module`, it has no semantic meaning beyond keeping the body of a `module`
-    well-formed.
-  }];
-  let assemblyFormat = "attr-dict";
-}
-
 //===----------------------------------------------------------------------===//
 // UnrealizedConversionCastOp
 //===----------------------------------------------------------------------===//
diff --git a/mlir/include/mlir/IR/OpBase.td b/mlir/include/mlir/IR/OpBase.td
--- a/mlir/include/mlir/IR/OpBase.td
+++ b/mlir/include/mlir/IR/OpBase.td
@@ -1808,6 +1808,9 @@
   ];
 }
 
+// Op's regions have a single block.
+def SingleBlock : NativeOpTrait<"SingleBlock">;
+
 // Op's regions have a single block with the specified terminator.
 class SingleBlockImplicitTerminator<string op>
     : ParamNativeOpTrait<"SingleBlockImplicitTerminator", op>;
diff --git a/mlir/include/mlir/IR/OpDefinition.h b/mlir/include/mlir/IR/OpDefinition.h
--- a/mlir/include/mlir/IR/OpDefinition.h
+++ b/mlir/include/mlir/IR/OpDefinition.h
@@ -675,6 +675,11 @@
 //===----------------------------------------------------------------------===//
 // Terminator Traits
 
+/// This class indicates that the regions associated with this op don't have
+/// terminators.
+template <typename ConcreteType>
+class NoTerminator : public TraitBase<ConcreteType, NoTerminator> {};
+
 /// This class provides the API for ops that are known to be terminators.
 template <typename ConcreteType>
 class IsTerminator : public TraitBase<ConcreteType, IsTerminator> {
@@ -778,6 +783,88 @@
     : public detail::MultiSuccessorTraitBase<ConcreteType, VariadicSuccessors> {
 };
 
+//===----------------------------------------------------------------------===//
+// SingleBlock
+
+/// This class provides APIs and verifiers for ops with regions having a single
+/// block.
+template <typename ConcreteType>
+struct SingleBlock : public TraitBase<ConcreteType, SingleBlock> {
+public:
+  static LogicalResult verifyTrait(Operation *op) {
+    for (unsigned i = 0, e = op->getNumRegions(); i < e; ++i) {
+      Region &region = op->getRegion(i);
+
+      // Empty regions are fine.
+      if (region.empty())
+        continue;
+
+      // Non-empty regions must contain a single basic block.
+      if (!llvm::hasSingleElement(region))
+        return op->emitOpError("expects region #")
+               << i << " to have 0 or 1 blocks";
+
+      if (!ConcreteType::template hasTrait<NoTerminator>()) {
+        Block &block = region.front();
+        if (block.empty())
+          return op->emitOpError() << "expects a non-empty block";
+      }
+    }
+    return success();
+  }
+
+  Block *getBody(unsigned idx = 0) {
+    Region &region = this->getOperation()->getRegion(idx);
+    assert(!region.empty() && "unexpected empty region");
+    return &region.front();
+  }
+  Region &getBodyRegion(unsigned idx = 0) {
+    return this->getOperation()->getRegion(idx);
+  }
+
+  //===------------------------------------------------------------------===//
+  // Single Region Utilities
+  //===------------------------------------------------------------------===//
+
+  /// The following are a set of methods only enabled when the parent
+  /// operation has a single region. Each of these methods take an additional
+  /// template parameter that represents the concrete operation so that we
+  /// can use SFINAE to disable the methods for non-single region operations.
+  template <typename OpT, typename T = void>
+  using enable_if_single_region =
+      typename std::enable_if_t<OpT::template hasTrait<OneRegion>(), T>;
+
+  template <typename OpT = ConcreteType>
+  enable_if_single_region<OpT, Block::iterator> begin() {
+    return getBody()->begin();
+  }
+  template <typename OpT = ConcreteType>
+  enable_if_single_region<OpT, Block::iterator> end() {
+    return getBody()->end();
+  }
+  template <typename OpT = ConcreteType>
+  enable_if_single_region<OpT, Operation &> front() {
+    return *begin();
+  }
+
+  /// Insert the operation into the back of the body.
+  template <typename OpT = ConcreteType>
+  enable_if_single_region<OpT> push_back(Operation *op) {
+    insert(Block::iterator(getBody()->end()), op);
+  }
+
+  /// Insert the operation at the given insertion point.
+  template <typename OpT = ConcreteType>
+  enable_if_single_region<OpT> insert(Operation *insertPt, Operation *op) {
+    insert(Block::iterator(insertPt), op);
+  }
+  template <typename OpT = ConcreteType>
+  enable_if_single_region<OpT> insert(Block::iterator insertPt, Operation *op) {
+    auto *body = getBody();
+    body->getOperations().insert(insertPt, op);
+  }
+};
+
 //===----------------------------------------------------------------------===//
 // SingleBlockImplicitTerminator
 
@@ -786,8 +873,9 @@
 template <typename TerminatorOpType>
 struct SingleBlockImplicitTerminator {
   template <typename ConcreteType>
-  class Impl : public TraitBase<ConcreteType, Impl> {
+  class Impl : public SingleBlock<ConcreteType> {
   private:
+    using Base = SingleBlock<ConcreteType>;
     /// Builds a terminator operation without relying on OpBuilder APIs to avoid
     /// cyclic header inclusion.
     static Operation *buildTerminator(OpBuilder &builder, Location loc) {
@@ -801,22 +889,14 @@
     using ImplicitTerminatorOpT = TerminatorOpType;
 
     static LogicalResult verifyTrait(Operation *op) {
+      if (failed(Base::verifyTrait(op)))
+        return failure();
       for (unsigned i = 0, e = op->getNumRegions(); i < e; ++i) {
         Region &region = op->getRegion(i);
-
         // Empty regions are fine.
         if (region.empty())
           continue;
-
-        // Non-empty regions must contain a single basic block.
-        if (std::next(region.begin()) != region.end())
-          return op->emitOpError("expects region #")
-                 << i << " to have 0 or 1 blocks";
-
-        Block &block = region.front();
-        if (block.empty())
-          return op->emitOpError() << "expects a non-empty block";
-        Operation &terminator = block.back();
+        Operation &terminator = region.front().back();
         if (isa<TerminatorOpType>(terminator))
           continue;
 
@@ -849,40 +929,15 @@
                                            buildTerminator);
     }
 
-    Block *getBody(unsigned idx = 0) {
-      Region &region = this->getOperation()->getRegion(idx);
-      assert(!region.empty() && "unexpected empty region");
-      return &region.front();
-    }
-    Region &getBodyRegion(unsigned idx = 0) {
-      return this->getOperation()->getRegion(idx);
-    }
-
     //===------------------------------------------------------------------===//
     // Single Region Utilities
     //===------------------------------------------------------------------===//
+    using Base::getBody;
 
-    /// The following are a set of methods only enabled when the parent
-    /// operation has a single region. Each of these methods take an additional
-    /// template parameter that represents the concrete operation so that we
-    /// can use SFINAE to disable the methods for non-single region operations.
     template <typename OpT, typename T = void>
     using enable_if_single_region =
         typename std::enable_if_t<OpT::template hasTrait<OneRegion>(), T>;
 
-    template <typename OpT = ConcreteType>
-    enable_if_single_region<OpT, Block::iterator> begin() {
-      return getBody()->begin();
-    }
-    template <typename OpT = ConcreteType>
-    enable_if_single_region<OpT, Block::iterator> end() {
-      return getBody()->end();
-    }
-    template <typename OpT = ConcreteType>
-    enable_if_single_region<OpT, Operation &> front() {
-      return *begin();
-    }
-
     /// Insert the operation into the back of the body, before the terminator.
     template <typename OpT = ConcreteType>
     enable_if_single_region<OpT> push_back(Operation *op) {
diff --git a/mlir/include/mlir/IR/OpImplementation.h b/mlir/include/mlir/IR/OpImplementation.h
--- a/mlir/include/mlir/IR/OpImplementation.h
+++ b/mlir/include/mlir/IR/OpImplementation.h
@@ -92,8 +92,13 @@
   virtual void printGenericOp(Operation *op) = 0;
 
   /// Prints a region.
+  /// If 'printEntryBlockArgs' is false, the arguments of the
+  /// block are not printed. If 'printBlockTerminator' is false, the terminator
+  /// operation of the block is not printed. If printEmptyBlock is true, then
+  /// the block header is printed even if the block is empty.
   virtual void printRegion(Region &blocks, bool printEntryBlockArgs = true,
-                           bool printBlockTerminators = true) = 0;
+                           bool printBlockTerminators = true,
+                           bool printEmptyBlock = false) = 0;
 
   /// Renumber the arguments for the specified region to the same names as the
   /// SSA values in namesToUse.  This may only be used for IsolatedFromAbove
diff --git a/mlir/include/mlir/IR/Region.h b/mlir/include/mlir/IR/Region.h
--- a/mlir/include/mlir/IR/Region.h
+++ b/mlir/include/mlir/IR/Region.h
@@ -43,6 +43,10 @@
 
   using BlockListType = llvm::iplist<Block>;
   BlockListType &getBlocks() { return blocks; }
+  Block &emplaceBlock() {
+    push_back(new Block);
+    return back();
+  }
 
   // Iteration over the blocks in the region.
   using iterator = BlockListType::iterator;
diff --git a/mlir/include/mlir/IR/RegionKindInterface.h b/mlir/include/mlir/IR/RegionKindInterface.h
--- a/mlir/include/mlir/IR/RegionKindInterface.h
+++ b/mlir/include/mlir/IR/RegionKindInterface.h
@@ -28,6 +28,16 @@
   Graph,
 };
 
+namespace OpTrait {
+/// A trait that specifies that an operation only defines graph regions.
+template <typename ConcreteType>
+class HasOnlyGraphRegion : public TraitBase<ConcreteType, HasOnlyGraphRegion> {
+public:
+  static RegionKind getRegionKind(unsigned index) { return RegionKind::Graph; }
+  static bool hasSSADominance(unsigned index) { return false; }
+};
+} // namespace OpTrait
+
 } // namespace mlir
 
 #include "mlir/IR/RegionKindInterface.h.inc"
diff --git a/mlir/include/mlir/IR/RegionKindInterface.td b/mlir/include/mlir/IR/RegionKindInterface.td
--- a/mlir/include/mlir/IR/RegionKindInterface.td
+++ b/mlir/include/mlir/IR/RegionKindInterface.td
@@ -50,4 +50,17 @@
   ];
 }
 
+def HasOnlyGraphRegion : NativeOpTrait<"HasOnlyGraphRegion">;
+
+// Op's regions that don't need a terminator: requires some other traits
+// so it defines a list that must be concatenated.
+def NoTerminator {
+  list<OpTrait> traits = [
+    NativeOpTrait<"NoTerminator">,
+    SingleBlock,
+    RegionKindInterface,
+    HasOnlyGraphRegion
+  ];
+}
+
 #endif // MLIR_IR_REGIONKINDINTERFACE
diff --git a/mlir/include/mlir/Parser.h b/mlir/include/mlir/Parser.h
--- a/mlir/include/mlir/Parser.h
+++ b/mlir/include/mlir/Parser.h
@@ -37,12 +37,11 @@
     Block *parsedBlock, MLIRContext *context, Location sourceFileLoc) {
   static_assert(
       ContainerOpT::template hasTrait<OpTrait::OneRegion>() &&
-          std::is_base_of<typename OpTrait::SingleBlockImplicitTerminator<
-                              typename ContainerOpT::ImplicitTerminatorOpT>::
-                              template Impl<ContainerOpT>,
-                          ContainerOpT>::value,
+          (ContainerOpT::template hasTrait<OpTrait::NoTerminator>() ||
+           ContainerOpT::template hasTrait<
+               OpTrait::SingleBlockImplicitTerminator>()),
       "Expected `ContainerOpT` to have a single region with a single "
-      "block that has an implicit terminator");
+      "block that has an implicit terminator or does not require one");
 
   // Check to see if we parsed a single instance of this operation.
   if (llvm::hasSingleElement(*parsedBlock)) {
diff --git a/mlir/lib/Bindings/Python/mlir/dialects/_builtin_ops_ext.py b/mlir/lib/Bindings/Python/mlir/dialects/_builtin_ops_ext.py
--- a/mlir/lib/Bindings/Python/mlir/dialects/_builtin_ops_ext.py
+++ b/mlir/lib/Bindings/Python/mlir/dialects/_builtin_ops_ext.py
@@ -11,8 +11,6 @@
     super().__init__(self.build_generic(results=[], operands=[], loc=loc,
                                         ip=ip))
     body = self.regions[0].blocks.append()
-    with InsertionPoint(body):
-      Operation.create("module_terminator")
 
   @property
   def body(self):
diff --git a/mlir/lib/Conversion/AsyncToLLVM/AsyncToLLVM.cpp b/mlir/lib/Conversion/AsyncToLLVM/AsyncToLLVM.cpp
--- a/mlir/lib/Conversion/AsyncToLLVM/AsyncToLLVM.cpp
+++ b/mlir/lib/Conversion/AsyncToLLVM/AsyncToLLVM.cpp
@@ -156,8 +156,8 @@
 
 /// Adds Async Runtime C API declarations to the module.
 static void addAsyncRuntimeApiDeclarations(ModuleOp module) {
-  auto builder = ImplicitLocOpBuilder::atBlockTerminator(module.getLoc(),
-                                                         module.getBody());
+  auto builder =
+      ImplicitLocOpBuilder::atBlockEnd(module.getLoc(), module.getBody());
 
   auto addFuncDecl = [&](StringRef name, FunctionType type) {
     if (module.lookupSymbol(name))
@@ -207,8 +207,8 @@
   using namespace mlir::LLVM;
 
   MLIRContext *ctx = module.getContext();
-  ImplicitLocOpBuilder builder(module.getLoc(),
-                               module.getBody()->getTerminator());
+  auto builder =
+      ImplicitLocOpBuilder::atBlockEnd(module.getLoc(), module.getBody());
 
   auto voidTy = LLVMVoidType::get(ctx);
   auto i64 = IntegerType::get(ctx, 64);
@@ -232,15 +232,14 @@
     return;
 
   MLIRContext *ctx = module.getContext();
-
-  OpBuilder moduleBuilder(module.getBody()->getTerminator());
-  Location loc = module.getLoc();
+  auto loc = module.getLoc();
+  auto moduleBuilder = ImplicitLocOpBuilder::atBlockEnd(loc, module.getBody());
 
   auto voidTy = LLVM::LLVMVoidType::get(ctx);
   auto i8Ptr = LLVM::LLVMPointerType::get(IntegerType::get(ctx, 8));
 
   auto resumeOp = moduleBuilder.create<LLVM::LLVMFuncOp>(
-      loc, kResume, LLVM::LLVMFunctionType::get(voidTy, {i8Ptr}));
+      kResume, LLVM::LLVMFunctionType::get(voidTy, {i8Ptr}));
   resumeOp.setPrivate();
 
   auto *block = resumeOp.addEntryBlock();
diff --git a/mlir/lib/Conversion/GPUCommon/ConvertLaunchFuncToRuntimeCalls.cpp b/mlir/lib/Conversion/GPUCommon/ConvertLaunchFuncToRuntimeCalls.cpp
--- a/mlir/lib/Conversion/GPUCommon/ConvertLaunchFuncToRuntimeCalls.cpp
+++ b/mlir/lib/Conversion/GPUCommon/ConvertLaunchFuncToRuntimeCalls.cpp
@@ -329,7 +329,7 @@
   auto function = [&] {
     if (auto function = module.lookupSymbol<LLVM::LLVMFuncOp>(functionName))
       return function;
-    return OpBuilder(module.getBody()->getTerminator())
+    return OpBuilder::atBlockEnd(module.getBody())
         .create<LLVM::LLVMFuncOp>(loc, functionName, functionType);
   }();
   return builder.create<LLVM::CallOp>(
diff --git a/mlir/lib/Conversion/GPUToVulkan/ConvertGPULaunchFuncToVulkanLaunchFunc.cpp b/mlir/lib/Conversion/GPUToVulkan/ConvertGPULaunchFuncToVulkanLaunchFunc.cpp
--- a/mlir/lib/Conversion/GPUToVulkan/ConvertGPULaunchFuncToVulkanLaunchFunc.cpp
+++ b/mlir/lib/Conversion/GPUToVulkan/ConvertGPULaunchFuncToVulkanLaunchFunc.cpp
@@ -99,7 +99,7 @@
 
 LogicalResult ConvertGpuLaunchFuncToVulkanLaunchFunc::declareVulkanLaunchFunc(
     Location loc, gpu::LaunchFuncOp launchOp) {
-  OpBuilder builder(getOperation().getBody()->getTerminator());
+  auto builder = OpBuilder::atBlockEnd(getOperation().getBody());
 
   // Workgroup size is written into the kernel. So to properly modelling
   // vulkan launch, we have to skip local workgroup size configuration here.
diff --git a/mlir/lib/Conversion/GPUToVulkan/ConvertLaunchFuncToVulkanCalls.cpp b/mlir/lib/Conversion/GPUToVulkan/ConvertLaunchFuncToVulkanCalls.cpp
--- a/mlir/lib/Conversion/GPUToVulkan/ConvertLaunchFuncToVulkanCalls.cpp
+++ b/mlir/lib/Conversion/GPUToVulkan/ConvertLaunchFuncToVulkanCalls.cpp
@@ -291,7 +291,7 @@
 
 void VulkanLaunchFuncToVulkanCallsPass::declareVulkanFunctions(Location loc) {
   ModuleOp module = getOperation();
-  OpBuilder builder(module.getBody()->getTerminator());
+  auto builder = OpBuilder::atBlockEnd(module.getBody());
 
   if (!module.lookupSymbol(kSetEntryPoint)) {
     builder.create<LLVM::LLVMFuncOp>(
diff --git a/mlir/lib/Conversion/LinalgToLLVM/LinalgToLLVM.cpp b/mlir/lib/Conversion/LinalgToLLVM/LinalgToLLVM.cpp
--- a/mlir/lib/Conversion/LinalgToLLVM/LinalgToLLVM.cpp
+++ b/mlir/lib/Conversion/LinalgToLLVM/LinalgToLLVM.cpp
@@ -227,7 +227,7 @@
 
   LLVMConversionTarget target(getContext());
   target.addIllegalOp<RangeOp>();
-  target.addLegalOp<ModuleOp, ModuleTerminatorOp, LLVM::DialectCastOp>();
+  target.addLegalOp<ModuleOp, LLVM::DialectCastOp>();
   if (failed(applyPartialConversion(module, target, std::move(patterns))))
     signalPassFailure();
 }
diff --git a/mlir/lib/Conversion/LinalgToSPIRV/LinalgToSPIRVPass.cpp b/mlir/lib/Conversion/LinalgToSPIRV/LinalgToSPIRVPass.cpp
--- a/mlir/lib/Conversion/LinalgToSPIRV/LinalgToSPIRVPass.cpp
+++ b/mlir/lib/Conversion/LinalgToSPIRV/LinalgToSPIRVPass.cpp
@@ -35,7 +35,7 @@
   populateBuiltinFuncToSPIRVPatterns(context, typeConverter, patterns);
 
   // Allow builtin ops.
-  target->addLegalOp<ModuleOp, ModuleTerminatorOp>();
+  target->addLegalOp<ModuleOp>();
   target->addDynamicallyLegalOp<FuncOp>([&](FuncOp op) {
     return typeConverter.isSignatureLegal(op.getType()) &&
            typeConverter.isLegal(&op.getBody());
diff --git a/mlir/lib/Conversion/LinalgToStandard/LinalgToStandard.cpp b/mlir/lib/Conversion/LinalgToStandard/LinalgToStandard.cpp
--- a/mlir/lib/Conversion/LinalgToStandard/LinalgToStandard.cpp
+++ b/mlir/lib/Conversion/LinalgToStandard/LinalgToStandard.cpp
@@ -216,7 +216,7 @@
   ConversionTarget target(getContext());
   target.addLegalDialect<AffineDialect, memref::MemRefDialect, scf::SCFDialect,
                          StandardOpsDialect>();
-  target.addLegalOp<ModuleOp, FuncOp, ModuleTerminatorOp, ReturnOp>();
+  target.addLegalOp<ModuleOp, FuncOp, ReturnOp>();
   target.addLegalOp<linalg::ReshapeOp, linalg::RangeOp>();
   OwningRewritePatternList patterns;
   populateLinalgToStandardConversionPatterns(patterns, &getContext());
diff --git a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
--- a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
+++ b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVM.cpp
@@ -1361,7 +1361,7 @@
   matchAndRewrite(spirv::ModuleEndOp moduleEndOp, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const override {
 
-    rewriter.replaceOpWithNewOp<ModuleTerminatorOp>(moduleEndOp);
+    rewriter.eraseOp(moduleEndOp);
     return success();
   }
 };
diff --git a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVMPass.cpp b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVMPass.cpp
--- a/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVMPass.cpp
+++ b/mlir/lib/Conversion/SPIRVToLLVM/SPIRVToLLVMPass.cpp
@@ -48,10 +48,8 @@
   target.addIllegalDialect<spirv::SPIRVDialect>();
   target.addLegalDialect<LLVM::LLVMDialect>();
 
-  // Set `ModuleOp` and `ModuleTerminatorOp` as legal for `spv.module`
-  // conversion.
+  // Set `ModuleOp` as legal for `spv.module` conversion.
   target.addLegalOp<ModuleOp>();
-  target.addLegalOp<ModuleTerminatorOp>();
   if (failed(applyPartialConversion(module, target, std::move(patterns))))
     signalPassFailure();
 }
diff --git a/mlir/lib/Conversion/ShapeToStandard/ShapeToStandard.cpp b/mlir/lib/Conversion/ShapeToStandard/ShapeToStandard.cpp
--- a/mlir/lib/Conversion/ShapeToStandard/ShapeToStandard.cpp
+++ b/mlir/lib/Conversion/ShapeToStandard/ShapeToStandard.cpp
@@ -675,7 +675,7 @@
   ConversionTarget target(ctx);
   target.addLegalDialect<memref::MemRefDialect, StandardOpsDialect, SCFDialect,
                          tensor::TensorDialect>();
-  target.addLegalOp<CstrRequireOp, FuncOp, ModuleOp, ModuleTerminatorOp>();
+  target.addLegalOp<CstrRequireOp, FuncOp, ModuleOp>();
 
   // Setup conversion patterns.
   OwningRewritePatternList patterns;
diff --git a/mlir/lib/Conversion/VectorToSPIRV/VectorToSPIRVPass.cpp b/mlir/lib/Conversion/VectorToSPIRV/VectorToSPIRVPass.cpp
--- a/mlir/lib/Conversion/VectorToSPIRV/VectorToSPIRVPass.cpp
+++ b/mlir/lib/Conversion/VectorToSPIRV/VectorToSPIRVPass.cpp
@@ -40,7 +40,7 @@
   OwningRewritePatternList patterns;
   populateVectorToSPIRVPatterns(context, typeConverter, patterns);
 
-  target->addLegalOp<ModuleOp, ModuleTerminatorOp>();
+  target->addLegalOp<ModuleOp>();
   target->addLegalOp<FuncOp>();
 
   if (failed(applyFullConversion(module, *target, std::move(patterns))))
diff --git a/mlir/lib/Dialect/Async/Transforms/AsyncToAsyncRuntime.cpp b/mlir/lib/Dialect/Async/Transforms/AsyncToAsyncRuntime.cpp
--- a/mlir/lib/Dialect/Async/Transforms/AsyncToAsyncRuntime.cpp
+++ b/mlir/lib/Dialect/Async/Transforms/AsyncToAsyncRuntime.cpp
@@ -199,7 +199,7 @@
   // TODO: Derive outlined function name from the parent FuncOp (support
   // multiple nested async.execute operations).
   FuncOp func = FuncOp::create(loc, kAsyncFnPrefix, funcType, funcAttrs);
-  symbolTable.insert(func, Block::iterator(module.getBody()->getTerminator()));
+  symbolTable.insert(func);
 
   SymbolTable::setSymbolVisibility(func, SymbolTable::Visibility::Private);
 
diff --git a/mlir/lib/Dialect/StandardOps/Transforms/FuncBufferize.cpp b/mlir/lib/Dialect/StandardOps/Transforms/FuncBufferize.cpp
--- a/mlir/lib/Dialect/StandardOps/Transforms/FuncBufferize.cpp
+++ b/mlir/lib/Dialect/StandardOps/Transforms/FuncBufferize.cpp
@@ -43,8 +43,7 @@
     populateBranchOpInterfaceTypeConversionPattern(patterns, context,
                                                    typeConverter);
     populateReturnOpTypeConversionPattern(patterns, context, typeConverter);
-    target.addLegalOp<ModuleOp, ModuleTerminatorOp, memref::TensorLoadOp,
-                      memref::BufferCastOp>();
+    target.addLegalOp<ModuleOp, memref::TensorLoadOp, memref::BufferCastOp>();
 
     target.markUnknownOpDynamicallyLegal([&](Operation *op) {
       return isNotBranchOpInterfaceOrReturnLikeOp(op) ||
diff --git a/mlir/lib/IR/AsmPrinter.cpp b/mlir/lib/IR/AsmPrinter.cpp
--- a/mlir/lib/IR/AsmPrinter.cpp
+++ b/mlir/lib/IR/AsmPrinter.cpp
@@ -418,7 +418,8 @@
 
   /// Print the given region.
   void printRegion(Region &region, bool printEntryBlockArgs,
-                   bool printBlockTerminators) override {
+                   bool printBlockTerminators,
+                   bool printEmptyBlock = false) override {
     if (region.empty())
       return;
 
@@ -2324,7 +2325,7 @@
 
   /// Print the given region.
   void printRegion(Region &region, bool printEntryBlockArgs,
-                   bool printBlockTerminators) override;
+                   bool printBlockTerminators, bool printEmptyBlock) override;
 
   /// Renumber the arguments for the specified region to the same names as the
   /// SSA values in namesToUse. This may only be used for IsolatedFromAbove
@@ -2435,7 +2436,7 @@
     os << " (";
     interleaveComma(op->getRegions(), [&](Region &region) {
       printRegion(region, /*printEntryBlockArgs=*/true,
-                  /*printBlockTerminators=*/true);
+                  /*printBlockTerminators=*/true, /*printEmptyBlock=*/true);
     });
     os << ')';
   }
@@ -2536,12 +2537,18 @@
 }
 
 void OperationPrinter::printRegion(Region &region, bool printEntryBlockArgs,
-                                   bool printBlockTerminators) {
+                                   bool printBlockTerminators,
+                                   bool printEmptyBlock) {
   os << " {" << newLine;
   if (!region.empty()) {
     auto *entryBlock = &region.front();
-    print(entryBlock, printEntryBlockArgs && entryBlock->getNumArguments() != 0,
-          printBlockTerminators);
+    // Force printing the block header if printEmptyBlock is set and the block
+    // is empty or if printEntryBlockArgs is set and there are arguments to
+    // print.
+    bool shouldAlwaysPrintBlockHeader =
+        (printEmptyBlock && entryBlock->empty()) ||
+        (printEntryBlockArgs && entryBlock->getNumArguments() != 0);
+    print(entryBlock, shouldAlwaysPrintBlockHeader, printBlockTerminators);
     for (auto &b : llvm::drop_begin(region.getBlocks(), 1))
       print(&b);
   }
diff --git a/mlir/lib/IR/Block.cpp b/mlir/lib/IR/Block.cpp
--- a/mlir/lib/IR/Block.cpp
+++ b/mlir/lib/IR/Block.cpp
@@ -294,6 +294,21 @@
   return newBB;
 }
 
+/// Returns true if this block may be valid without terminator. That is if:
+/// - it does not have a parent region.
+/// - Or the parent region have a single block and:
+///    - This region does not have a parent op.
+///    - Or the parent op is unregistered.
+///    - Or the parent op has the NoTerminator trait.
+bool Block::mayNotHaveTerminator() {
+  if (!getParent())
+    return true;
+  if (!llvm::hasSingleElement(*getParent()))
+    return false;
+  Operation *op = getParentOp();
+  return !op || op->mightHaveTrait<OpTrait::NoTerminator>();
+}
+
 //===----------------------------------------------------------------------===//
 // Predecessors
 //===----------------------------------------------------------------------===//
@@ -314,9 +329,11 @@
 SuccessorRange::SuccessorRange() : SuccessorRange(nullptr, 0) {}
 
 SuccessorRange::SuccessorRange(Block *block) : SuccessorRange() {
-  if (Operation *term = block->getTerminator())
+  if (!llvm::hasSingleElement(*block->getParent())) {
+    Operation *term = block->getTerminator();
     if ((count = term->getNumSuccessors()))
       base = term->getBlockOperands().data();
+  }
 }
 
 SuccessorRange::SuccessorRange(Operation *term) : SuccessorRange() {
diff --git a/mlir/lib/IR/BuiltinDialect.cpp b/mlir/lib/IR/BuiltinDialect.cpp
--- a/mlir/lib/IR/BuiltinDialect.cpp
+++ b/mlir/lib/IR/BuiltinDialect.cpp
@@ -209,7 +209,7 @@
 
 void ModuleOp::build(OpBuilder &builder, OperationState &state,
                      Optional<StringRef> name) {
-  ensureTerminator(*state.addRegion(), builder, state.location);
+  state.addRegion()->emplaceBlock();
   if (name) {
     state.attributes.push_back(builder.getNamedAttr(
         mlir::SymbolTable::getSymbolAttrName(), builder.getStringAttr(*name)));
diff --git a/mlir/lib/IR/SymbolTable.cpp b/mlir/lib/IR/SymbolTable.cpp
--- a/mlir/lib/IR/SymbolTable.cpp
+++ b/mlir/lib/IR/SymbolTable.cpp
@@ -161,11 +161,17 @@
   // TODO: consider if SymbolTable's constructor should behave the same.
   if (!symbol->getParentOp()) {
     auto &body = symbolTableOp->getRegion(0).front();
-    if (insertPt == Block::iterator() || insertPt == body.end())
-      insertPt = Block::iterator(body.getTerminator());
-
-    assert(insertPt->getParentOp() == symbolTableOp &&
-           "expected insertPt to be in the associated module operation");
+    if (insertPt == Block::iterator()) {
+      insertPt = Block::iterator(body.end());
+    } else {
+      assert((insertPt == body.end() ||
+              insertPt->getParentOp() == symbolTableOp) &&
+             "expected insertPt to be in the associated module operation");
+    }
+    // Insert before the terminator, if any.
+    if (insertPt == Block::iterator(body.end()) && !body.empty() &&
+        std::prev(body.end())->hasTrait<OpTrait::IsTerminator>())
+      insertPt = std::prev(body.end());
 
     body.getOperations().insert(insertPt, symbol);
   }
@@ -291,11 +297,14 @@
 Operation *SymbolTable::lookupSymbolIn(Operation *symbolTableOp,
                                        StringRef symbol) {
   assert(symbolTableOp->hasTrait<OpTrait::SymbolTable>());
+  Region &region0 = symbolTableOp->getRegion(0);
+  if (region0.empty())
+    return nullptr;
 
   // Look for a symbol with the given name.
   Identifier symbolNameId = Identifier::get(SymbolTable::getSymbolAttrName(),
                                             symbolTableOp->getContext());
-  for (auto &op : symbolTableOp->getRegion(0).front().without_terminator())
+  for (auto &op : region0.front())
     if (getNameIfSymbol(&op, symbolNameId) == symbol)
       return &op;
   return nullptr;
diff --git a/mlir/lib/IR/Verifier.cpp b/mlir/lib/IR/Verifier.cpp
--- a/mlir/lib/IR/Verifier.cpp
+++ b/mlir/lib/IR/Verifier.cpp
@@ -119,11 +119,15 @@
       return emitError(block, "block argument not owned by block");
 
   // Verify that this block has a terminator.
-  if (block.empty())
-    return emitError(block, "block with no terminator");
+
+  if (block.empty()) {
+    if (block.mayNotHaveTerminator())
+      return success();
+    return emitError(block, "empty block: expect at least a terminator");
+  }
 
   // Verify the non-terminator operations separately so that we can verify
-  // they has no successors.
+  // they have no successors.
   for (auto &op : llvm::make_range(block.begin(), std::prev(block.end()))) {
     if (op.getNumSuccessors() != 0)
       return op.emitError(
@@ -137,8 +141,13 @@
   Operation &terminator = block.back();
   if (failed(verifyOperation(terminator)))
     return failure();
+
+  if (block.mayNotHaveTerminator())
+    return success();
+
   if (!terminator.mightHaveTrait<OpTrait::IsTerminator>())
-    return block.back().emitError("block with no terminator");
+    return block.back().emitError("block with no terminator, has ")
+           << terminator;
 
   // Verify that this block is not branching to a block of a different
   // region.
@@ -176,13 +185,14 @@
   unsigned numRegions = op.getNumRegions();
   for (unsigned i = 0; i < numRegions; i++) {
     Region &region = op.getRegion(i);
+    RegionKind kind =
+        kindInterface ? kindInterface.getRegionKind(i) : RegionKind::SSACFG;
     // Check that Graph Regions only have a single basic block. This is
     // similar to the code in SingleBlockImplicitTerminator, but doesn't
     // require the trait to be specified. This arbitrary limitation is
     // designed to limit the number of cases that have to be handled by
     // transforms and conversions until the concept stabilizes.
-    if (op.isRegistered() && kindInterface &&
-        kindInterface.getRegionKind(i) == RegionKind::Graph) {
+    if (op.isRegistered() && kind == RegionKind::Graph) {
       // Empty regions are fine.
       if (region.empty())
         continue;
diff --git a/mlir/lib/Parser/Parser.cpp b/mlir/lib/Parser/Parser.cpp
--- a/mlir/lib/Parser/Parser.cpp
+++ b/mlir/lib/Parser/Parser.cpp
@@ -2064,7 +2064,7 @@
       auto &parsedOps = (*topLevelOp)->getRegion(0).front().getOperations();
       auto &destOps = topLevelBlock->getOperations();
       destOps.splice(destOps.empty() ? destOps.end() : std::prev(destOps.end()),
-                     parsedOps, parsedOps.begin(), std::prev(parsedOps.end()));
+                     parsedOps, parsedOps.begin(), parsedOps.end());
       return success();
     }
 
diff --git a/mlir/lib/Target/LLVMIR/ConvertFromLLVMIR.cpp b/mlir/lib/Target/LLVMIR/ConvertFromLLVMIR.cpp
--- a/mlir/lib/Target/LLVMIR/ConvertFromLLVMIR.cpp
+++ b/mlir/lib/Target/LLVMIR/ConvertFromLLVMIR.cpp
@@ -269,10 +269,11 @@
 
   /// Globals are inserted before the first function, if any.
   Block::iterator getGlobalInsertPt() {
-    auto i = module.getBody()->begin();
-    while (!isa<LLVMFuncOp, ModuleTerminatorOp>(i))
-      ++i;
-    return i;
+    auto it = module.getBody()->begin();
+    auto endIt = module.getBody()->end();
+    while (it != endIt && !isa<LLVMFuncOp>(it))
+      ++it;
+    return it;
   }
 
   /// Functions are always inserted before the module terminator.
diff --git a/mlir/lib/Transforms/SymbolDCE.cpp b/mlir/lib/Transforms/SymbolDCE.cpp
--- a/mlir/lib/Transforms/SymbolDCE.cpp
+++ b/mlir/lib/Transforms/SymbolDCE.cpp
@@ -61,8 +61,7 @@
     if (!nestedSymbolTable->hasTrait<OpTrait::SymbolTable>())
       return;
     for (auto &block : nestedSymbolTable->getRegion(0)) {
-      for (Operation &op :
-           llvm::make_early_inc_range(block.without_terminator())) {
+      for (Operation &op : llvm::make_early_inc_range(block)) {
         if (isa<SymbolOpInterface>(&op) && !liveSymbols.count(&op))
           op.erase();
       }
@@ -84,7 +83,7 @@
   // are known to be live.
   for (auto &block : symbolTableOp->getRegion(0)) {
     // Add all non-symbols or symbols that can't be discarded.
-    for (Operation &op : block.without_terminator()) {
+    for (Operation &op : block) {
       SymbolOpInterface symbol = dyn_cast<SymbolOpInterface>(&op);
       if (!symbol) {
         worklist.push_back(&op);
diff --git a/mlir/lib/Transforms/Utils/RegionUtils.cpp b/mlir/lib/Transforms/Utils/RegionUtils.cpp
--- a/mlir/lib/Transforms/Utils/RegionUtils.cpp
+++ b/mlir/lib/Transforms/Utils/RegionUtils.cpp
@@ -311,6 +311,7 @@
   for (Region &region : regions) {
     if (region.empty())
       continue;
+    bool hasSingleBlock = llvm::hasSingleElement(region);
 
     // We do the deletion in an order that deletes all uses before deleting
     // defs.
@@ -322,7 +323,8 @@
     // before domtree parents. A CFG post-order (with reverse iteration with a
     // block) satisfies that without needing an explicit domtree calculation.
     for (Block *block : llvm::post_order(&region.front())) {
-      eraseTerminatorSuccessorOperands(block->getTerminator(), liveMap);
+      if (!hasSingleBlock)
+        eraseTerminatorSuccessorOperands(block->getTerminator(), liveMap);
       for (Operation &childOp :
            llvm::make_early_inc_range(llvm::reverse(block->getOperations()))) {
         if (!liveMap.wasProvenLive(&childOp)) {
diff --git a/mlir/test/Bindings/Python/context_managers.py b/mlir/test/Bindings/Python/context_managers.py
--- a/mlir/test/Bindings/Python/context_managers.py
+++ b/mlir/test/Bindings/Python/context_managers.py
@@ -62,7 +62,7 @@
 def testInsertionPointEnterExit():
   ctx1 = Context()
   m = Module.create(Location.unknown(ctx1))
-  ip = InsertionPoint.at_block_terminator(m.body)
+  ip = InsertionPoint(m.body)
 
   with ip:
     assert InsertionPoint.current is ip
diff --git a/mlir/test/Bindings/Python/dialects.py b/mlir/test/Bindings/Python/dialects.py
--- a/mlir/test/Bindings/Python/dialects.py
+++ b/mlir/test/Bindings/Python/dialects.py
@@ -77,7 +77,7 @@
     ctx.allow_unregistered_dialects = True
     m = Module.create()
 
-    with InsertionPoint.at_block_terminator(m.body):
+    with InsertionPoint(m.body):
       f32 = F32Type.get()
       # Create via dialects context collection.
       input1 = createInput()
diff --git a/mlir/test/Bindings/Python/dialects/linalg/ops.py b/mlir/test/Bindings/Python/dialects/linalg/ops.py
--- a/mlir/test/Bindings/Python/dialects/linalg/ops.py
+++ b/mlir/test/Bindings/Python/dialects/linalg/ops.py
@@ -17,7 +17,7 @@
     module = Module.create()
     f32 = F32Type.get()
     tensor_type = RankedTensorType.get((2, 3, 4), f32)
-    with InsertionPoint.at_block_terminator(module.body):
+    with InsertionPoint(module.body):
       func = builtin.FuncOp(name="matmul_test",
                             type=FunctionType.get(
                                 inputs=[tensor_type, tensor_type],
@@ -40,7 +40,7 @@
     module = Module.create()
     f32 = F32Type.get()
     memref_type = MemRefType.get((2, 3, 4), f32)
-    with InsertionPoint.at_block_terminator(module.body):
+    with InsertionPoint(module.body):
       func = builtin.FuncOp(name="matmul_test",
                             type=FunctionType.get(
                                 inputs=[memref_type, memref_type, memref_type],
diff --git a/mlir/test/Bindings/Python/insertion_point.py b/mlir/test/Bindings/Python/insertion_point.py
--- a/mlir/test/Bindings/Python/insertion_point.py
+++ b/mlir/test/Bindings/Python/insertion_point.py
@@ -129,8 +129,13 @@
 def test_insert_at_end_with_terminator_errors():
   with Context() as ctx, Location.unknown():
     ctx.allow_unregistered_dialects = True
-    m = Module.create()  # Module is created with a terminator.
-    with InsertionPoint(m.body):
+    module = Module.parse(r"""
+      func @foo() -> () {
+        return
+      }
+    """)
+    entry_block = module.body.operations[0].regions[0].blocks[0]
+    with InsertionPoint(entry_block):
       try:
         Operation.create("custom.op1", results=[], operands=[])
       except IndexError as e:
diff --git a/mlir/test/Bindings/Python/ir_operation.py b/mlir/test/Bindings/Python/ir_operation.py
--- a/mlir/test/Bindings/Python/ir_operation.py
+++ b/mlir/test/Bindings/Python/ir_operation.py
@@ -64,7 +64,6 @@
   # CHECK:         BLOCK 0:
   # CHECK:           OP 0: %0 = "custom.addi"
   # CHECK:           OP 1: return
-  # CHECK:    OP 1: module_terminator
   walk_operations("", op)
 
 run(testTraverseOpRegionBlockIterators)
@@ -101,7 +100,6 @@
   # CHECK:         BLOCK 0:
   # CHECK:           OP 0: %0 = "custom.addi"
   # CHECK:           OP 1: return
-  # CHECK:    OP 1: module_terminator
   walk_operations("", module.operation)
 
 run(testTraverseOpRegionBlockIndices)
@@ -546,9 +544,9 @@
 def testPrintInvalidOperation():
   ctx = Context()
   with Location.unknown(ctx):
-    module = Operation.create("module", regions=1)
-    # This block does not have a terminator, it may crash the custom printer.
-    # Verify that we fallback to the generic printer for safety.
+    module = Operation.create("module", regions=2)
+    # This module has two region and is invalid verify that we fallback
+    # to the generic printer for safety.
     block = module.regions[0].blocks.append()
     # CHECK: // Verification failed, printing generic form
     # CHECK: "module"() ( {
diff --git a/mlir/test/Bindings/Python/ods_helpers.py b/mlir/test/Bindings/Python/ods_helpers.py
--- a/mlir/test/Bindings/Python/ods_helpers.py
+++ b/mlir/test/Bindings/Python/ods_helpers.py
@@ -29,7 +29,7 @@
   with Context() as ctx, Location.unknown():
     ctx.allow_unregistered_dialects = True
     m = Module.create()
-    with InsertionPoint.at_block_terminator(m.body):
+    with InsertionPoint(m.body):
       op = TestFixedRegionsOp.build_generic(results=[], operands=[])
       # CHECK: NUM_REGIONS: 2
       print(f"NUM_REGIONS: {len(op.regions)}")
@@ -84,7 +84,7 @@
   with Context() as ctx, Location.unknown():
     ctx.allow_unregistered_dialects = True
     m = Module.create()
-    with InsertionPoint.at_block_terminator(m.body):
+    with InsertionPoint(m.body):
       v0 = add_dummy_value()
       v1 = add_dummy_value()
       t0 = IntegerType.get_signless(8)
@@ -111,7 +111,7 @@
   with Context() as ctx, Location.unknown():
     ctx.allow_unregistered_dialects = True
     m = Module.create()
-    with InsertionPoint.at_block_terminator(m.body):
+    with InsertionPoint(m.body):
       v0 = add_dummy_value()
       v1 = add_dummy_value()
       v2 = add_dummy_value()
@@ -187,7 +187,7 @@
   with Context() as ctx, Location.unknown():
     ctx.allow_unregistered_dialects = True
     m = Module.create()
-    with InsertionPoint.at_block_terminator(m.body):
+    with InsertionPoint(m.body):
       v0 = add_dummy_value()
       v1 = add_dummy_value()
       t0 = IntegerType.get_signless(8)
diff --git a/mlir/test/Bindings/Python/pass_manager.py b/mlir/test/Bindings/Python/pass_manager.py
--- a/mlir/test/Bindings/Python/pass_manager.py
+++ b/mlir/test/Bindings/Python/pass_manager.py
@@ -91,6 +91,5 @@
 # CHECK: Operations encountered:
 # CHECK: func              , 1
 # CHECK: module            , 1
-# CHECK: module_terminator , 1
 # CHECK: std.return        , 1
 run(testRunPipeline)
diff --git a/mlir/test/CAPI/ir.c b/mlir/test/CAPI/ir.c
--- a/mlir/test/CAPI/ir.c
+++ b/mlir/test/CAPI/ir.c
@@ -293,7 +293,7 @@
   fprintf(stderr, "Number of op results: %u\n", stats.numOpResults);
   // clang-format off
   // CHECK-LABEL: @stats
-  // CHECK: Number of operations: 13
+  // CHECK: Number of operations: 12
   // CHECK: Number of attributes: 4
   // CHECK: Number of blocks: 3
   // CHECK: Number of regions: 3
diff --git a/mlir/test/CAPI/pass.c b/mlir/test/CAPI/pass.c
--- a/mlir/test/CAPI/pass.c
+++ b/mlir/test/CAPI/pass.c
@@ -42,7 +42,6 @@
   // Run the print-op-stats pass on the top-level module:
   // CHECK-LABEL: Operations encountered:
   // CHECK: func              , 1
-  // CHECK: module_terminator , 1
   // CHECK: std.addi          , 1
   // CHECK: std.return        , 1
   {
@@ -84,7 +83,6 @@
 
   // Run the print-op-stats pass on functions under the top-level module:
   // CHECK-LABEL: Operations encountered:
-  // CHECK-NOT: module_terminator
   // CHECK: func              , 1
   // CHECK: std.addi          , 1
   // CHECK: std.return        , 1
@@ -101,7 +99,6 @@
   }
   // Run the print-op-stats pass on functions under the nested module:
   // CHECK-LABEL: Operations encountered:
-  // CHECK-NOT: module_terminator
   // CHECK: func              , 1
   // CHECK: std.addf          , 1
   // CHECK: std.return        , 1
diff --git a/mlir/test/IR/invalid-module-op.mlir b/mlir/test/IR/invalid-module-op.mlir
--- a/mlir/test/IR/invalid-module-op.mlir
+++ b/mlir/test/IR/invalid-module-op.mlir
@@ -19,31 +19,12 @@
   // expected-error@+1 {{region should have no arguments}}
   module {
   ^bb1(%arg: i32):
-    "module_terminator"() : () -> ()
-  }
-  return
-}
-
-// -----
-
-func @module_op() {
-  // expected-error@below {{expects regions to end with 'module_terminator'}}
-  // expected-note@below {{the absence of terminator implies 'module_terminator'}}
-  module {
-    return
   }
   return
 }
 
 // -----
 
-func @module_op() {
-  // expected-error@+1 {{expects parent op 'module'}}
-  "module_terminator"() : () -> ()
-}
-
-// -----
-
 // expected-error@+1 {{can only contain attributes with dialect-prefixed names}}
 module attributes {attr} {
 }
diff --git a/mlir/test/IR/invalid.mlir b/mlir/test/IR/invalid.mlir
--- a/mlir/test/IR/invalid.mlir
+++ b/mlir/test/IR/invalid.mlir
@@ -120,7 +120,7 @@
 
 // -----
 
-func @no_terminator() {   // expected-error {{block with no terminator}}
+func @no_terminator() {   // expected-error {{empty block: expect at least a terminator}}
 ^bb40:
   return
 ^bb41:
diff --git a/mlir/test/IR/module-op.mlir b/mlir/test/IR/module-op.mlir
--- a/mlir/test/IR/module-op.mlir
+++ b/mlir/test/IR/module-op.mlir
@@ -4,16 +4,14 @@
 module {
 }
 
-// CHECK: module {
-// CHECK-NEXT: }
-module {
-  "module_terminator"() : () -> ()
-}
+// -----
 
 // CHECK: module attributes {foo.attr = true} {
 module attributes {foo.attr = true} {
 }
 
+// -----
+
 // CHECK: module {
 module {
   // CHECK-NEXT: "foo.result_op"() : () -> i32
diff --git a/mlir/test/IR/print-ir-defuse.mlir b/mlir/test/IR/print-ir-defuse.mlir
--- a/mlir/test/IR/print-ir-defuse.mlir
+++ b/mlir/test/IR/print-ir-defuse.mlir
@@ -18,8 +18,6 @@
 // CHECK: Has 0 results:
 // CHECK: Visiting op 'dialect.op3' with 0 operands:
 // CHECK: Has 0 results:
-// CHECK: Visiting op 'module_terminator' with 0 operands:
-// CHECK: Has 0 results:
 // CHECK: Visiting op 'module' with 0 operands:
 // CHECK: Has 0 results:
 
diff --git a/mlir/test/IR/print-ir-nesting.mlir b/mlir/test/IR/print-ir-nesting.mlir
--- a/mlir/test/IR/print-ir-nesting.mlir
+++ b/mlir/test/IR/print-ir-nesting.mlir
@@ -3,7 +3,7 @@
 // CHECK: visiting op: 'module' with 0 operands and 0 results
 // CHECK:  1 nested regions:
 // CHECK:   Region with 1 blocks:
-// CHECK:     Block with 0 arguments, 0 successors, and 3 operations
+// CHECK:     Block with 0 arguments, 0 successors, and 2 operations
 module {
 
 
@@ -52,6 +52,4 @@
     "dialect.innerop7"() : () -> ()
   }) : () -> ()
 
-// CHECK:       visiting op: 'module_terminator' with 0 operands and 0 results
-
 } // module
diff --git a/mlir/test/IR/region.mlir b/mlir/test/IR/region.mlir
--- a/mlir/test/IR/region.mlir
+++ b/mlir/test/IR/region.mlir
@@ -73,3 +73,11 @@
     }) : () -> ()
     return
 }
+
+// -----
+
+// Region with single block and not terminator.
+// CHECK: unregistered_without_terminator
+"test.unregistered_without_terminator"() ( {
+  ^bb0:  // no predecessors
+}) : () -> ()
diff --git a/mlir/test/Transforms/test-legalizer-analysis.mlir b/mlir/test/Transforms/test-legalizer-analysis.mlir
--- a/mlir/test/Transforms/test-legalizer-analysis.mlir
+++ b/mlir/test/Transforms/test-legalizer-analysis.mlir
@@ -1,6 +1,5 @@
 // RUN: mlir-opt -allow-unregistered-dialect -test-legalize-patterns -verify-diagnostics -test-legalize-mode=analysis %s | FileCheck %s
 // expected-remark@-2 {{op 'module' is legalizable}}
-// expected-remark@-3 {{op 'module_terminator' is legalizable}}
 
 // expected-remark@+1 {{op 'func' is legalizable}}
 func @test(%arg0: f32) {
diff --git a/mlir/test/lib/Dialect/Test/TestPatterns.cpp b/mlir/test/lib/Dialect/Test/TestPatterns.cpp
--- a/mlir/test/lib/Dialect/Test/TestPatterns.cpp
+++ b/mlir/test/lib/Dialect/Test/TestPatterns.cpp
@@ -575,7 +575,7 @@
 
     // Define the conversion target used for the test.
     ConversionTarget target(getContext());
-    target.addLegalOp<ModuleOp, ModuleTerminatorOp>();
+    target.addLegalOp<ModuleOp>();
     target.addLegalOp<LegalOpA, LegalOpB, TestCastOp, TestValidOp,
                       TerminatorOp>();
     target
@@ -704,7 +704,7 @@
     patterns.insert<OneVResOneVOperandOp1Converter>(&getContext());
 
     mlir::ConversionTarget target(getContext());
-    target.addLegalOp<ModuleOp, ModuleTerminatorOp, FuncOp, TestReturnOp>();
+    target.addLegalOp<ModuleOp, FuncOp, TestReturnOp>();
     // We make OneVResOneVOperandOp1 legal only when it has more that one
     // operand. This will trigger the conversion that will replace one-operand
     // OneVResOneVOperandOp1 with two-operand OneVResOneVOperandOp1.
@@ -972,9 +972,8 @@
         .insert<TestMergeBlock, TestUndoBlocksMerge, TestMergeSingleBlockOps>(
             context);
     ConversionTarget target(*context);
-    target.addLegalOp<FuncOp, ModuleOp, ModuleTerminatorOp, TerminatorOp,
-                      TestBranchOp, TestTypeConsumerOp, TestTypeProducerOp,
-                      TestReturnOp>();
+    target.addLegalOp<FuncOp, ModuleOp, TerminatorOp, TestBranchOp,
+                      TestTypeConsumerOp, TestTypeProducerOp, TestReturnOp>();
     target.addIllegalOp<ILLegalOpF>();
 
     /// Expect the op to have a single block after legalization.
diff --git a/mlir/test/lib/Transforms/TestConvVectorization.cpp b/mlir/test/lib/Transforms/TestConvVectorization.cpp
--- a/mlir/test/lib/Transforms/TestConvVectorization.cpp
+++ b/mlir/test/lib/Transforms/TestConvVectorization.cpp
@@ -56,7 +56,7 @@
   ConversionTarget target(*context);
   target.addLegalDialect<AffineDialect, scf::SCFDialect, StandardOpsDialect,
                          VectorDialect>();
-  target.addLegalOp<ModuleOp, FuncOp, ModuleTerminatorOp, ReturnOp>();
+  target.addLegalOp<ModuleOp, FuncOp, ReturnOp>();
   target.addLegalOp<linalg::FillOp, linalg::YieldOp>();
 
   SmallVector<OwningRewritePatternList, 4> stage1Patterns;
diff --git a/mlir/tools/mlir-tblgen/OpFormatGen.cpp b/mlir/tools/mlir-tblgen/OpFormatGen.cpp
--- a/mlir/tools/mlir-tblgen/OpFormatGen.cpp
+++ b/mlir/tools/mlir-tblgen/OpFormatGen.cpp
@@ -437,6 +437,14 @@
         llvm::any_of(op.getTraits(), [](const OpTrait &trait) {
           return trait.getDef().isSubClassOf("SingleBlockImplicitTerminator");
         });
+
+    hasSingleBlockTrait =
+        hasImplicitTermTrait ||
+        llvm::any_of(op.getTraits(), [](const OpTrait &trait) {
+          if (auto *native = dyn_cast<NativeOpTrait>(&trait))
+            return native->getTrait() == "::mlir::OpTrait::SingleBlock";
+          return false;
+        });
   }
 
   /// Generate the operation parser from this format.
@@ -472,6 +480,9 @@
   /// trait.
   bool hasImplicitTermTrait;
 
+  /// A flag indicating if this operation has the SingleBlock trait.
+  bool hasSingleBlockTrait;
+
   /// A map of buildable types to indices.
   llvm::MapVector<StringRef, int, llvm::StringMap<int>> buildableTypes;
 
@@ -667,6 +678,14 @@
     ensureTerminator(*region, parser.getBuilder(), result.location);
 )";
 
+/// The code snippet used to ensure a list of regions have a block.
+///
+/// {0}: The name of the region list.
+const char *regionListEnsureSingleBlockParserCode = R"(
+  for (auto &region : {0}Regions)
+    if (region.empty()) *{0}Region.emplaceBlock();
+)";
+
 /// The code snippet used to generate a parser call for an optional region.
 ///
 /// {0}: The name of the region.
@@ -693,6 +712,13 @@
   ensureTerminator(*{0}Region, parser.getBuilder(), result.location);
 )";
 
+/// The code snippet used to ensure a region has a block.
+///
+/// {0}: The name of the region.
+const char *regionEnsureSingleBlockParserCode = R"(
+  if ({0}Region->empty()) {0}Region->emplaceBlock();
+)";
+
 /// The code snippet used to generate a parser call for a successor list.
 ///
 /// {0}: The name for the successor list.
@@ -1120,6 +1146,9 @@
         body << "  if (!" << region->name << "Region->empty()) {\n  ";
         if (hasImplicitTermTrait)
           body << llvm::formatv(regionEnsureTerminatorParserCode, region->name);
+        else if (hasSingleBlockTrait)
+          body << llvm::formatv(regionEnsureSingleBlockParserCode,
+                                region->name);
       }
     }
 
@@ -1193,11 +1222,14 @@
     bool isVariadic = region->getVar()->isVariadic();
     body << llvm::formatv(isVariadic ? regionListParserCode : regionParserCode,
                           region->getVar()->name);
-    if (hasImplicitTermTrait) {
+    if (hasImplicitTermTrait)
       body << llvm::formatv(isVariadic ? regionListEnsureTerminatorParserCode
                                        : regionEnsureTerminatorParserCode,
                             region->getVar()->name);
-    }
+    else if (hasSingleBlockTrait)
+      body << llvm::formatv(isVariadic ? regionListEnsureSingleBlockParserCode
+                                       : regionEnsureSingleBlockParserCode,
+                            region->getVar()->name);
 
   } else if (auto *successor = dyn_cast<SuccessorVariable>(element)) {
     bool isVariadic = successor->getVar()->isVariadic();
@@ -1222,6 +1254,8 @@
     body << llvm::formatv(regionListParserCode, "full");
     if (hasImplicitTermTrait)
       body << llvm::formatv(regionListEnsureTerminatorParserCode, "full");
+    else if (hasSingleBlockTrait)
+      body << llvm::formatv(regionListEnsureSingleBlockParserCode, "full");
 
   } else if (isa<SuccessorsDirective>(element)) {
     body << llvm::formatv(successorListParserCode, "full");