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
@@ -191,6 +191,10 @@
   interleaveComma(types, p);
   return p;
 }
+inline OpAsmPrinter &operator<<(OpAsmPrinter &p, ArrayRef<Type> types) {
+  interleaveComma(types, p);
+  return p;
+}
 
 //===----------------------------------------------------------------------===//
 // OpAsmParser
diff --git a/mlir/include/mlir/IR/Operation.h b/mlir/include/mlir/IR/Operation.h
--- a/mlir/include/mlir/IR/Operation.h
+++ b/mlir/include/mlir/IR/Operation.h
@@ -260,10 +260,10 @@
 
   /// Support result type iteration.
   using result_type_iterator = result_range::type_iterator;
-  using result_type_range = iterator_range<result_type_iterator>;
-  result_type_iterator result_type_begin() { return result_begin(); }
-  result_type_iterator result_type_end() { return result_end(); }
-  result_type_range getResultTypes() { return getResults().getTypes(); }
+  using result_type_range = ArrayRef<Type>;
+  result_type_iterator result_type_begin() { return getResultTypes().begin(); }
+  result_type_iterator result_type_end() { return getResultTypes().end(); }
+  result_type_range getResultTypes();
 
   //===--------------------------------------------------------------------===//
   // Attributes
diff --git a/mlir/include/mlir/IR/OperationSupport.h b/mlir/include/mlir/IR/OperationSupport.h
--- a/mlir/include/mlir/IR/OperationSupport.h
+++ b/mlir/include/mlir/IR/OperationSupport.h
@@ -595,8 +595,8 @@
   ResultRange(Operation *op);
 
   /// Returns the types of the values within this range.
-  using type_iterator = ValueTypeIterator<iterator>;
-  iterator_range<type_iterator> getTypes() const { return {begin(), end()}; }
+  using type_iterator = ArrayRef<Type>::iterator;
+  ArrayRef<Type> getTypes() const;
 
 private:
   /// See `indexed_accessor_range` for details.
diff --git a/mlir/lib/Analysis/InferTypeOpInterface.cpp b/mlir/lib/Analysis/InferTypeOpInterface.cpp
--- a/mlir/lib/Analysis/InferTypeOpInterface.cpp
+++ b/mlir/lib/Analysis/InferTypeOpInterface.cpp
@@ -53,8 +53,8 @@
                                         op->getOperands(), op->getAttrs(),
                                         op->getRegions(), inferedReturnTypes)))
     return failure();
-  SmallVector<Type, 4> resultTypes(op->getResultTypes());
-  if (!retTypeFn.isCompatibleReturnTypes(inferedReturnTypes, resultTypes))
+  if (!retTypeFn.isCompatibleReturnTypes(inferedReturnTypes,
+                                         op->getResultTypes()))
     return op->emitOpError(
         "inferred type incompatible with return type of operation");
   return success();
diff --git a/mlir/lib/Conversion/StandardToLLVM/ConvertStandardToLLVM.cpp b/mlir/lib/Conversion/StandardToLLVM/ConvertStandardToLLVM.cpp
--- a/mlir/lib/Conversion/StandardToLLVM/ConvertStandardToLLVM.cpp
+++ b/mlir/lib/Conversion/StandardToLLVM/ConvertStandardToLLVM.cpp
@@ -652,8 +652,7 @@
 
     Type packedType;
     if (numResults != 0) {
-      packedType = this->lowering.packFunctionResults(
-          llvm::to_vector<4>(op->getResultTypes()));
+      packedType = this->lowering.packFunctionResults(op->getResultTypes());
       if (!packedType)
         return this->matchFailure();
     }
diff --git a/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp b/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
--- a/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
+++ b/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
@@ -292,11 +292,11 @@
   p.printOptionalAttrDict(op.getAttrs(), {"callee"});
 
   // Reconstruct the function MLIR function type from operand and result types.
-  SmallVector<Type, 1> resultTypes(op.getResultTypes());
   SmallVector<Type, 8> argTypes(
       llvm::drop_begin(op.getOperandTypes(), isDirect ? 0 : 1));
 
-  p << " : " << FunctionType::get(argTypes, resultTypes, op.getContext());
+  p << " : "
+    << FunctionType::get(argTypes, op.getResultTypes(), op.getContext());
 }
 
 // <operation> ::= `llvm.call` (function-id | ssa-use) `(` ssa-use-list `)`
diff --git a/mlir/lib/Dialect/SPIRV/SPIRVOps.cpp b/mlir/lib/Dialect/SPIRV/SPIRVOps.cpp
--- a/mlir/lib/Dialect/SPIRV/SPIRVOps.cpp
+++ b/mlir/lib/Dialect/SPIRV/SPIRVOps.cpp
@@ -1666,9 +1666,8 @@
 
 static void print(spirv::FunctionCallOp functionCallOp, OpAsmPrinter &printer) {
   SmallVector<Type, 4> argTypes(functionCallOp.getOperandTypes());
-  SmallVector<Type, 1> resultTypes(functionCallOp.getResultTypes());
-  Type functionType =
-      FunctionType::get(argTypes, resultTypes, functionCallOp.getContext());
+  Type functionType = FunctionType::get(
+      argTypes, functionCallOp.getResultTypes(), functionCallOp.getContext());
 
   printer << spirv::FunctionCallOp::getOperationName() << ' '
           << functionCallOp.getAttr(kCallee) << '('
diff --git a/mlir/lib/Dialect/SPIRV/Serialization/Serializer.cpp b/mlir/lib/Dialect/SPIRV/Serialization/Serializer.cpp
--- a/mlir/lib/Dialect/SPIRV/Serialization/Serializer.cpp
+++ b/mlir/lib/Dialect/SPIRV/Serialization/Serializer.cpp
@@ -1764,12 +1764,9 @@
   auto funcName = op.callee();
   uint32_t resTypeID = 0;
 
-  SmallVector<Type, 1> resultTypes(op.getResultTypes());
-  if (failed(processType(op.getLoc(),
-                         (resultTypes.empty() ? getVoidType() : resultTypes[0]),
-                         resTypeID))) {
+  Type resultTy = op.getNumResults() ? *op.result_type_begin() : getVoidType();
+  if (failed(processType(op.getLoc(), resultTy, resTypeID)))
     return failure();
-  }
 
   auto funcID = getOrCreateFunctionID(funcName);
   auto funcCallID = getNextID();
@@ -1781,9 +1778,8 @@
     operands.push_back(valueID);
   }
 
-  if (!resultTypes.empty()) {
+  if (!resultTy.isa<NoneType>())
     valueIDMap[op.getResult(0)] = funcCallID;
-  }
 
   return encodeInstructionInto(functionBody, spirv::Opcode::OpFunctionCall,
                                operands);
diff --git a/mlir/lib/Dialect/StandardOps/Ops.cpp b/mlir/lib/Dialect/StandardOps/Ops.cpp
--- a/mlir/lib/Dialect/StandardOps/Ops.cpp
+++ b/mlir/lib/Dialect/StandardOps/Ops.cpp
@@ -503,9 +503,8 @@
 }
 
 FunctionType CallOp::getCalleeType() {
-  SmallVector<Type, 4> resultTypes(getResultTypes());
   SmallVector<Type, 8> argTypes(getOperandTypes());
-  return FunctionType::get(argTypes, resultTypes, getContext());
+  return FunctionType::get(argTypes, getResultTypes(), getContext());
 }
 
 //===----------------------------------------------------------------------===//
@@ -525,8 +524,8 @@
       return matchFailure();
 
     // Replace with a direct call.
-    SmallVector<Type, 8> callResults(indirectCall.getResultTypes());
-    rewriter.replaceOpWithNewOp<CallOp>(indirectCall, calledFn, callResults,
+    rewriter.replaceOpWithNewOp<CallOp>(indirectCall, calledFn,
+                                        indirectCall.getResultTypes(),
                                         indirectCall.getArgOperands());
     return matchSuccess();
   }
diff --git a/mlir/lib/IR/Operation.cpp b/mlir/lib/IR/Operation.cpp
--- a/mlir/lib/IR/Operation.cpp
+++ b/mlir/lib/IR/Operation.cpp
@@ -551,6 +551,14 @@
   return hasSingleResult ? 1 : resultType.cast<TupleType>().size();
 }
 
+auto Operation::getResultTypes() -> result_type_range {
+  if (!resultType)
+    return llvm::None;
+  if (hasSingleResult)
+    return resultType;
+  return resultType.cast<TupleType>().getTypes();
+}
+
 void Operation::setSuccessor(Block *block, unsigned index) {
   assert(index < getNumSuccessors());
   getBlockOperands()[index].set(block);
@@ -666,10 +674,9 @@
     }
   }
 
-  SmallVector<Type, 8> resultTypes(getResultTypes());
   unsigned numRegions = getNumRegions();
   auto *newOp =
-      Operation::create(getLoc(), getName(), resultTypes, operands, attrs,
+      Operation::create(getLoc(), getName(), getResultTypes(), operands, attrs,
                         successors, numRegions, hasResizableOperandsList());
 
   // Remember the mapping of any results.
@@ -919,7 +926,7 @@
 
   auto type = op->getResult(0).getType();
   auto elementType = getElementTypeOrSelf(type);
-  for (auto resultType : llvm::drop_begin(op->getResultTypes(), 1)) {
+  for (auto resultType : op->getResultTypes().drop_front(1)) {
     if (getElementTypeOrSelf(resultType) != elementType ||
         failed(verifyCompatibleShape(resultType, type)))
       return op->emitOpError()
diff --git a/mlir/lib/IR/OperationSupport.cpp b/mlir/lib/IR/OperationSupport.cpp
--- a/mlir/lib/IR/OperationSupport.cpp
+++ b/mlir/lib/IR/OperationSupport.cpp
@@ -152,6 +152,10 @@
 ResultRange::ResultRange(Operation *op)
     : ResultRange(op, /*startIndex=*/0, op->getNumResults()) {}
 
+ArrayRef<Type> ResultRange::getTypes() const {
+  return getBase()->getResultTypes();
+}
+
 /// See `indexed_accessor_range` for details.
 OpResult ResultRange::dereference(Operation *op, ptrdiff_t index) {
   return op->getResult(index);
diff --git a/mlir/lib/Transforms/CSE.cpp b/mlir/lib/Transforms/CSE.cpp
--- a/mlir/lib/Transforms/CSE.cpp
+++ b/mlir/lib/Transforms/CSE.cpp
@@ -37,10 +37,9 @@
     //   - Attributes
     //   - Result Types
     //   - Operands
-    return hash_combine(
-        op->getName(), op->getAttrList().getDictionary(),
-        hash_combine_range(op->result_type_begin(), op->result_type_end()),
-        hash_combine_range(op->operand_begin(), op->operand_end()));
+    return llvm::hash_combine(
+        op->getName(), op->getAttrList().getDictionary(), op->getResultTypes(),
+        llvm::hash_combine_range(op->operand_begin(), op->operand_end()));
   }
   static bool isEqual(const Operation *lhsC, const Operation *rhsC) {
     auto *lhs = const_cast<Operation *>(lhsC);
diff --git a/mlir/test/lib/TestDialect/TestPatterns.cpp b/mlir/test/lib/TestDialect/TestPatterns.cpp
--- a/mlir/test/lib/TestDialect/TestPatterns.cpp
+++ b/mlir/test/lib/TestDialect/TestPatterns.cpp
@@ -241,7 +241,7 @@
   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const final {
     // If the type is I32, change the type to F32.
-    if (!(*op->result_type_begin()).isInteger(32))
+    if (!Type(*op->result_type_begin()).isInteger(32))
       return matchFailure();
     rewriter.replaceOpWithNewOp<TestTypeProducerOp>(op, rewriter.getF32Type());
     return matchSuccess();
@@ -254,7 +254,7 @@
   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const final {
     // If the type is F32, change the type to F64.
-    if (!(*op->result_type_begin()).isF32())
+    if (!Type(*op->result_type_begin()).isF32())
       return matchFailure();
     rewriter.replaceOpWithNewOp<TestTypeProducerOp>(op, rewriter.getF64Type());
     return matchSuccess();
@@ -472,8 +472,7 @@
     remappedOperands.push_back(rewriter.getRemappedValue(origOp));
     remappedOperands.push_back(rewriter.getRemappedValue(origOp));
 
-    SmallVector<Type, 1> resultTypes(op.getResultTypes());
-    rewriter.replaceOpWithNewOp<OneVResOneVOperandOp1>(op, resultTypes,
+    rewriter.replaceOpWithNewOp<OneVResOneVOperandOp1>(op, op.getResultTypes(),
                                                        remappedOperands);
     return matchSuccess();
   }