[Mlir-commits] [mlir] [MLIR] Introduce RemarkEngine + pluggable remark streaming (YAML/Bitstream) (PR #152474)

Guray Ozen llvmlistbot at llvm.org
Fri Aug 15 06:04:16 PDT 2025


https://github.com/grypp updated https://github.com/llvm/llvm-project/pull/152474

>From e4292d11d2b249a894af4113f032e72884853647 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Thu, 7 Aug 2025 10:01:51 +0000
Subject: [PATCH 01/22] [MLIR] MLIR Integrate LLVM Optimization Remarks
 Infrastructure
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This patch hooks LLVM’s remarks infrastructure into MLIR.

* Disabled by default, zero-cost when off.
  Enable per context with `MLIRContext::setupOptimizationRemarks(...)`.
* YAML or bitstream output: via new `MLIRRemarkStreamer`
  (subclasses `llvm::remarks::RemarkStreamer`).
* Implements simple APIs for passes:

User-code can directly prints remarks like:
```
reportOptimizationPass(loc, categoryName, "MyPass")        << "vectorized";
reportOptimizationMiss(loc, categoryLoopUnroll, "MyPass",
                       "try increasing unroll factor")      << "...";
reportOptimizationFail(loc, categoryLoopUnroll, "MyPass")  << "...";
reportOptimizationAnalysis(loc, categoryLoopUnroll, "MyPass")
                       << "estimated trip count: " << tripCount;
```
---
 mlir/include/mlir/IR/MLIRContext.h |  15 +
 mlir/include/mlir/IR/Remarks.h     | 454 +++++++++++++++++++++++++++++
 mlir/lib/IR/CMakeLists.txt         |   6 +
 mlir/lib/IR/MLIRContext.cpp        |  35 +++
 mlir/lib/IR/Remarks.cpp            | 296 +++++++++++++++++++
 mlir/unittests/IR/CMakeLists.txt   |   1 +
 mlir/unittests/IR/RemarkTest.cpp   | 106 +++++++
 7 files changed, 913 insertions(+)
 create mode 100644 mlir/include/mlir/IR/Remarks.h
 create mode 100644 mlir/lib/IR/Remarks.cpp
 create mode 100644 mlir/unittests/IR/RemarkTest.cpp

diff --git a/mlir/include/mlir/IR/MLIRContext.h b/mlir/include/mlir/IR/MLIRContext.h
index ef8dab87f131a..ab8f4aed3fc79 100644
--- a/mlir/include/mlir/IR/MLIRContext.h
+++ b/mlir/include/mlir/IR/MLIRContext.h
@@ -32,6 +32,7 @@ class InFlightDiagnostic;
 class Location;
 class MLIRContextImpl;
 class RegisteredOperationName;
+class RemarkEngine;
 class StorageUniquer;
 class IRUnit;
 
@@ -212,6 +213,9 @@ class MLIRContext {
   /// Returns the diagnostic engine for this context.
   DiagnosticEngine &getDiagEngine();
 
+  /// Returns the remark engine for this context.
+  std::unique_ptr<RemarkEngine> &getRemarkEngine();
+
   /// Returns the storage uniquer used for creating affine constructs.
   StorageUniquer &getAffineUniquer();
 
@@ -245,6 +249,14 @@ class MLIRContext {
   /// (attributes, operations, types, etc.).
   llvm::hash_code getRegistryHash();
 
+  /// Set up optimization remarks for the context.
+  void setupOptimizationRemarks(
+      StringRef outputPath, StringRef outputFormat, bool printAsEmitRemarks,
+      const std::optional<std::string> &categoryPassName = std::nullopt,
+      const std::optional<std::string> &categoryMissName = std::nullopt,
+      const std::optional<std::string> &categoryAnalysisName = std::nullopt,
+      const std::optional<std::string> &categoryFailedName = std::nullopt);
+
   //===--------------------------------------------------------------------===//
   // Action API
   //===--------------------------------------------------------------------===//
@@ -281,6 +293,9 @@ class MLIRContext {
   }
 
 private:
+  /// Set the remark engine for this context.
+  void setRemarkEngine(std::unique_ptr<RemarkEngine> engine);
+
   /// Return true if the given dialect is currently loading.
   bool isDialectLoading(StringRef dialectNamespace);
 
diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
new file mode 100644
index 0000000000000..8f7e7a900e7f1
--- /dev/null
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -0,0 +1,454 @@
+//===- Remarks.h - MLIR Optimization Remark ----------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines utilities for emitting optimization remarks.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_IR_REMARKS_H
+#define MLIR_IR_REMARKS_H
+
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/IR/DiagnosticPrinter.h"
+#include "llvm/Remarks/Remark.h"
+#include "llvm/Remarks/RemarkStreamer.h"
+#include "llvm/Support/ToolOutputFile.h"
+
+#include "mlir/IR/Diagnostics.h"
+#include "mlir/IR/MLIRContext.h"
+
+namespace mlir {
+
+/// Defines different remark kinds that can be used to categorize remarks.
+enum class RemarkKind {
+  OptimizationRemarkUnknown = 0,
+  OptimizationRemarkPass,
+  OptimizationRemarkMissed,
+  OptimizationRemarkFailure,
+  OptimizationRemarkAnalysis,
+};
+
+//===----------------------------------------------------------------------===//
+// Remark Base Class
+//===----------------------------------------------------------------------===//
+class RemarkBase : public llvm::DiagnosticInfo {
+
+public:
+  RemarkBase(RemarkKind remarkKind, DiagnosticSeverity severity,
+             const char *passName, StringRef remarkName, Location loc,
+             std::optional<StringRef> functionName = std::nullopt)
+      : llvm::DiagnosticInfo(makeLLVMKind(remarkKind),
+                             makeLLVMSeverity(severity)),
+        remarkKind(remarkKind), functionName(functionName), loc(loc),
+        passName(passName), remarkName(remarkName) {}
+
+  struct SetIsVerbose {};
+
+  struct SetExtraArgs {};
+
+  struct RemarkKeyValue {
+    std::string key;
+    std::string val;
+
+    explicit RemarkKeyValue(StringRef str = "") : key("String"), val(str) {}
+    RemarkKeyValue(StringRef key, Value value);
+    RemarkKeyValue(StringRef key, Type type);
+    RemarkKeyValue(StringRef key, StringRef s);
+    RemarkKeyValue(StringRef key, const char *s)
+        : RemarkKeyValue(key, StringRef(s)) {};
+    RemarkKeyValue(StringRef key, int n);
+    RemarkKeyValue(StringRef key, float n);
+    RemarkKeyValue(StringRef key, long n);
+    RemarkKeyValue(StringRef key, long long n);
+    RemarkKeyValue(StringRef key, unsigned n);
+    RemarkKeyValue(StringRef key, unsigned long n);
+    RemarkKeyValue(StringRef key, unsigned long long n);
+    RemarkKeyValue(StringRef key, bool b)
+        : key(key), val(b ? "true" : "false") {}
+  };
+
+  void insert(StringRef s);
+  void insert(RemarkKeyValue a);
+  void insert(SetIsVerbose v);
+  void insert(SetExtraArgs ea);
+
+  void print(llvm::DiagnosticPrinter &dp) const override;
+  void print() const;
+
+  virtual bool isEnabled() const = 0;
+  Location getLocation() const { return loc; }
+  llvm::remarks::RemarkLocation getRemarkLocation() const;
+  /// Diagnostic -> Remark
+  llvm::remarks::Remark generateRemark() const;
+
+  StringRef getFunction() const {
+    if (functionName)
+      return *functionName;
+    return "<unknown function>";
+  }
+  StringRef getPassName() const { return passName; }
+  StringRef getRemarkName() const { return remarkName; }
+  std::string getMsg() const;
+
+  bool isVerbose() const { return isVerboseRemark; }
+
+  ArrayRef<RemarkKeyValue> getArgs() const { return args; }
+
+  llvm::remarks::Type getRemarkType() const;
+
+protected:
+  /// Keeps the MLIR diagnostic kind, which is used to determine the
+  /// diagnostic kind in the LLVM remark streamer.
+  RemarkKind remarkKind;
+  /// Name of the convering function like interface
+  std::optional<std::string> functionName;
+
+  Location loc;
+  /// Name of the pass that triggers this report.
+  const char *passName;
+
+  /// Textual identifier for the remark (single-word, CamelCase). Can be used
+  /// by external tools reading the output file for optimization remarks to
+  /// identify the remark.
+  StringRef remarkName;
+
+  /// RemarkKeyValues collected via the streaming interface.
+  SmallVector<RemarkKeyValue, 4> args;
+
+  /// The remark is expected to be noisy.
+  bool isVerboseRemark = false;
+
+private:
+  /// Convert the MLIR diagnostic severity to LLVM diagnostic severity.
+  static llvm::DiagnosticSeverity
+  makeLLVMSeverity(DiagnosticSeverity severity) {
+    switch (severity) {
+    case DiagnosticSeverity::Note:
+      return llvm::DiagnosticSeverity::DS_Note;
+    case DiagnosticSeverity::Warning:
+      return llvm::DiagnosticSeverity::DS_Warning;
+    case DiagnosticSeverity::Error:
+      return llvm::DiagnosticSeverity::DS_Error;
+    case DiagnosticSeverity::Remark:
+      return llvm::DiagnosticSeverity::DS_Remark;
+    }
+    llvm_unreachable("Unknown diagnostic severity");
+  }
+  /// Convert the MLIR remark kind to LLVM diagnostic kind.
+  static llvm::DiagnosticKind makeLLVMKind(RemarkKind remarkKind) {
+    switch (remarkKind) {
+    case RemarkKind::OptimizationRemarkUnknown:
+      return llvm::DiagnosticKind::DK_Generic;
+    case RemarkKind::OptimizationRemarkPass:
+      return llvm::DiagnosticKind::DK_OptimizationRemark;
+    case RemarkKind::OptimizationRemarkMissed:
+      return llvm::DiagnosticKind::DK_OptimizationRemarkMissed;
+    case RemarkKind::OptimizationRemarkFailure:
+      return llvm::DiagnosticKind::DK_OptimizationFailure;
+    case RemarkKind::OptimizationRemarkAnalysis:
+      return llvm::DiagnosticKind::DK_OptimizationRemarkAnalysis;
+    }
+    llvm_unreachable("Unknown diagnostic kind");
+  }
+};
+
+// clang-format off
+template <class RemarkT>
+decltype(auto) operator<<(
+    RemarkT &&r,
+    std::enable_if_t<std::is_base_of_v<RemarkBase,
+                                       std::remove_reference_t<RemarkT>>,
+                     StringRef>
+        s) {
+  r.insert(s);
+  return std::forward<RemarkT>(r);
+}
+
+template <class RemarkT>
+decltype(auto) operator<<(
+    RemarkT &&r,
+    std::enable_if_t<std::is_base_of_v<RemarkBase,
+                                       std::remove_reference_t<RemarkT>>,
+                     RemarkBase::RemarkKeyValue>
+        a) {
+  r.insert(std::move(a));
+  return std::forward<RemarkT>(r);
+}
+
+template <class RemarkT>
+decltype(auto) operator<<(
+    RemarkT &&r,
+    std::enable_if_t<std::is_base_of_v<RemarkBase,
+                                       std::remove_reference_t<RemarkT>>,
+                     RemarkBase::SetIsVerbose>
+        v) {
+  r.insert(v);
+  return std::forward<RemarkT>(r);
+}
+
+template <class RemarkT>
+decltype(auto) operator<<(
+    RemarkT &&r,
+    std::enable_if_t<std::is_base_of_v<RemarkBase,
+                                       std::remove_reference_t<RemarkT>>,
+                     RemarkBase::SetExtraArgs>
+        ea) {
+  r.insert(ea);
+  return std::forward<RemarkT>(r);
+}
+// clang-format on
+
+//===----------------------------------------------------------------------===//
+// Shorthand aliases for different kinds of remarks.
+//===----------------------------------------------------------------------===//
+
+template <RemarkKind K, DiagnosticSeverity S>
+class OptRemarkBase final : public RemarkBase {
+public:
+  explicit OptRemarkBase(Location loc, StringRef passName, StringRef remarkName)
+      : RemarkBase(K, S, passName.data(), remarkName, loc) {}
+
+  bool isEnabled() const override { return true; }
+};
+
+using OptRemarkAnalysis = OptRemarkBase<RemarkKind::OptimizationRemarkAnalysis,
+                                        DiagnosticSeverity::Remark>;
+
+using OptRemarkPass = OptRemarkBase<RemarkKind::OptimizationRemarkPass,
+                                    DiagnosticSeverity::Remark>;
+
+using OptRemarkMissed = OptRemarkBase<RemarkKind::OptimizationRemarkMissed,
+                                      DiagnosticSeverity::Remark>;
+
+using OptRemarkFailure = OptRemarkBase<RemarkKind::OptimizationRemarkFailure,
+                                       DiagnosticSeverity::Remark>;
+
+class RemarkEngine;
+
+//===----------------------------------------------------------------------===//
+// InFlightRemark
+//===----------------------------------------------------------------------===//
+
+/// InFlightRemark is a RAII class that holds a reference to a RemarkBase
+/// instance and allows to build the remark using the << operator. The remark
+/// is emitted when the InFlightRemark instance is destroyed, which happens
+/// when the scope ends or when the InFlightRemark instance is moved.
+/// Similar to InFlightDiagnostic, but for remarks.
+class InFlightRemark {
+public:
+  explicit InFlightRemark(RemarkBase *diag) : remark(diag) {}
+  InFlightRemark(RemarkEngine &eng, RemarkBase *diag)
+      : owner(&eng), remark(diag) {}
+
+  InFlightRemark() = default; // empty ctor
+
+  template <typename T>
+  InFlightRemark &operator<<(T &&arg) {
+    if (remark)
+      *remark << std::forward<T>(arg);
+    return *this;
+  }
+
+  explicit operator bool() const { return remark != nullptr; }
+
+  ~InFlightRemark();
+
+  InFlightRemark(const InFlightRemark &) = delete;
+  InFlightRemark &operator=(const InFlightRemark &) = delete;
+  InFlightRemark(InFlightRemark &&) = default;
+  InFlightRemark &operator=(InFlightRemark &&) = default;
+
+private:
+  RemarkEngine *owner{nullptr};
+  std::unique_ptr<RemarkBase> remark;
+};
+
+//===----------------------------------------------------------------------===//
+// MLIR Remark Streamer
+//===----------------------------------------------------------------------===//
+
+class MLIRRemarkStreamer {
+  llvm::remarks::RemarkStreamer &remarkStreamer;
+
+public:
+  explicit MLIRRemarkStreamer(llvm::remarks::RemarkStreamer &remarkStreamer)
+      : remarkStreamer(remarkStreamer) {}
+
+  void streamOptimizationRemark(const RemarkBase &remark);
+};
+
+//===----------------------------------------------------------------------===//
+// Remark Engine (MLIR Context will own this class)
+//===----------------------------------------------------------------------===//
+
+class RemarkEngine {
+private:
+  /// The category for missed optimization remarks.
+  std::optional<llvm::Regex> missFilter;
+  /// The category for passed optimization remarks.
+  std::optional<llvm::Regex> passFilter;
+  /// The category for analysis remarks.
+  std::optional<llvm::Regex> analysisFilter;
+  /// The category for failed optimization remarks.
+  std::optional<llvm::Regex> failedFilter;
+  /// The output file for the remarks.
+  std::unique_ptr<llvm::ToolOutputFile> remarksFile;
+  /// The MLIR remark streamer that will be used to emit the remarks.
+  std::unique_ptr<MLIRRemarkStreamer> remarkStreamer;
+  std::unique_ptr<llvm::remarks::RemarkStreamer> llvmRemarkStreamer;
+  /// When is enabled, engine also prints remarks as mlir::emitRemarks.
+  bool printAsEmitRemarks;
+  /// The main MLIR remark streamer that will be used to emit the remarks.
+  MLIRRemarkStreamer *getLLVMRemarkStreamer() { return remarkStreamer.get(); }
+  const MLIRRemarkStreamer *getLLVMRemarkStreamer() const {
+    return remarkStreamer.get();
+  }
+  void
+  setLLVMRemarkStreamer(std::unique_ptr<MLIRRemarkStreamer> remarkStreamer) {
+    this->remarkStreamer = std::move(remarkStreamer);
+  }
+
+  /// Get the main MLIR remark streamer that will be used to emit the remarks.
+  llvm::remarks::RemarkStreamer *getMainRemarkStreamer() {
+    return llvmRemarkStreamer.get();
+  }
+  const llvm::remarks::RemarkStreamer *getMainRemarkStreamer() const {
+    return llvmRemarkStreamer.get();
+  }
+  /// Set the main remark streamer to be used by the engine.
+  void setMainRemarkStreamer(
+      std::unique_ptr<llvm::remarks::RemarkStreamer> mainRemarkStreamer) {
+    llvmRemarkStreamer = std::move(mainRemarkStreamer);
+  }
+
+  /// Return true if missed optimization remarks are enabled, override
+  /// to provide different implementation.
+  bool isMissedOptRemarkEnabled(StringRef categoryName) const;
+
+  /// Return true if passed optimization remarks are enabled, override
+  /// to provide different implementation.
+  bool isPassedOptRemarkEnabled(StringRef categoryName) const;
+
+  /// Return true if analysis optimization remarks are enabled, override
+  /// to provide different implementation.
+  bool isAnalysisOptRemarkEnabled(StringRef categoryName) const;
+
+  /// Return true if analysis optimization remarks are enabled, override
+  /// to provide different implementation.
+  bool isFailedOptRemarkEnabled(StringRef categoryName) const;
+
+  /// Return true if any type of remarks are enabled for this pass.
+  bool isAnyRemarkEnabled(StringRef categoryName) const {
+    return (isMissedOptRemarkEnabled(categoryName) ||
+            isPassedOptRemarkEnabled(categoryName) ||
+            isFailedOptRemarkEnabled(categoryName) ||
+            isAnalysisOptRemarkEnabled(categoryName));
+  }
+
+  /// Emit a remark using the given maker function, which should return
+  /// a RemarkBase instance. The remark will be emitted using the main
+  /// remark streamer.
+  template <typename RemarkT, typename... Args>
+  InFlightRemark makeRemark(Args &&...args);
+
+  template <typename RemarkT>
+  InFlightRemark
+  emitIfEnabled(Location loc, StringRef passName, StringRef category,
+                bool (RemarkEngine::*isEnabled)(StringRef) const);
+
+public:
+  RemarkEngine() = delete;
+  /// Constructs Remark engine with optional category names
+  RemarkEngine(bool printAsEmitRemarks,
+               std::optional<std::string> categoryPassName = std::nullopt,
+               std::optional<std::string> categoryMissName = std::nullopt,
+               std::optional<std::string> categoryAnalysisName = std::nullopt,
+               std::optional<std::string> categoryFailedName = std::nullopt);
+
+  /// Destructor that will close the output file and reset the
+  /// main remark streamer.
+  ~RemarkEngine();
+
+  /// Setup the remark engine with the given output path and format.
+  llvm::Error initialize(StringRef outputPath, StringRef outputFormat);
+
+  /// Report a diagnostic remark.
+  void report(const RemarkBase &&diag);
+
+  /// Report a successful remark, this will create an InFlightRemark
+  /// that can be used to build the remark using the << operator.
+  InFlightRemark emitOptimizationRemark(Location loc, StringRef passName,
+                                        StringRef category);
+  /// Report a missed optimization remark
+  /// that can be used to build the remark using the << operator.
+  InFlightRemark emitOptimizationRemarkMiss(Location loc, StringRef passName,
+                                            StringRef category);
+  /// Report a failed optimization remark, this will create an InFlightRemark
+  /// that can be used to build the remark using the << operator.
+  InFlightRemark emitOptimizationRemarkFailure(Location loc, StringRef passName,
+                                               StringRef category);
+  /// Report an analysis remark, this will create an InFlightRemark
+  /// that can be used to build the remark using the << operator.
+  InFlightRemark emitOptimizationRemarkAnalysis(Location loc,
+                                                StringRef passName,
+                                                StringRef category);
+};
+
+//===----------------------------------------------------------------------===//
+// Emitters
+//===----------------------------------------------------------------------===//
+
+using Suggestion = RemarkBase::RemarkKeyValue;
+inline Suggestion suggest(StringRef txt) { return {"Suggestion", txt}; }
+
+template <typename Fn, typename... Args>
+[[nodiscard]] inline InFlightRemark withEngine(Fn fn, Location loc,
+                                               Args &&...args) {
+  MLIRContext *ctx = loc->getContext();
+
+  auto &enginePtr = ctx->getRemarkEngine();
+
+  if (RemarkEngine *eng = enginePtr.get())
+    return (eng->*fn)(loc, std::forward<Args>(args)...);
+
+  return {};
+}
+
+/// Report an optimization remark that was passed.
+inline InFlightRemark reportOptimizationPass(Location loc, StringRef cat,
+                                             StringRef passName) {
+  return withEngine(&RemarkEngine::emitOptimizationRemark, loc, passName, cat);
+}
+
+/// Report an optimization remark that was missed.
+inline InFlightRemark reportOptimizationMiss(Location loc, StringRef cat,
+                                             StringRef passName,
+                                             StringRef suggestion) {
+  auto r =
+      withEngine(&RemarkEngine::emitOptimizationRemarkMiss, loc, passName, cat);
+  if (r)
+    r << suggest(suggestion);
+  return r;
+}
+/// Report an optimization failure remark.
+inline InFlightRemark reportOptimizationFail(Location loc, StringRef cat,
+                                             StringRef passName) {
+  return withEngine(&RemarkEngine::emitOptimizationRemarkFailure, loc, passName,
+                    cat);
+}
+
+/// Report an optimization analysis remark.
+inline InFlightRemark reportOptimizationAnalysis(Location loc, StringRef cat,
+                                                 StringRef passName) {
+  return withEngine(&RemarkEngine::emitOptimizationRemarkAnalysis, loc,
+                    passName, cat);
+}
+
+} // namespace mlir
+
+#endif // MLIR_IR_REMARKS_H
\ No newline at end of file
diff --git a/mlir/lib/IR/CMakeLists.txt b/mlir/lib/IR/CMakeLists.txt
index 3ef69cea18f0a..438e486f2ad4c 100644
--- a/mlir/lib/IR/CMakeLists.txt
+++ b/mlir/lib/IR/CMakeLists.txt
@@ -33,6 +33,7 @@ add_mlir_library(MLIRIR
   PatternMatch.cpp
   Region.cpp
   RegionKindInterface.cpp
+  Remarks.cpp
   SymbolTable.cpp
   TensorEncoding.cpp
   Types.cpp
@@ -69,5 +70,10 @@ add_mlir_library(MLIRIR
 
   LINK_LIBS PUBLIC
   MLIRSupport
+  
+  LINK_COMPONENTS
+    Remarks
+    Core
+    BitstreamReader  
   )
 
diff --git a/mlir/lib/IR/MLIRContext.cpp b/mlir/lib/IR/MLIRContext.cpp
index 2d5381d43f863..5a37de1481eb9 100644
--- a/mlir/lib/IR/MLIRContext.cpp
+++ b/mlir/lib/IR/MLIRContext.cpp
@@ -25,12 +25,14 @@
 #include "mlir/IR/Location.h"
 #include "mlir/IR/OpImplementation.h"
 #include "mlir/IR/OperationSupport.h"
+#include "mlir/IR/Remarks.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/Error.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Mutex.h"
 #include "llvm/Support/RWMutex.h"
@@ -133,6 +135,11 @@ class MLIRContextImpl {
   //===--------------------------------------------------------------------===//
   DiagnosticEngine diagEngine;
 
+  //===--------------------------------------------------------------------===//
+  // Remark
+  //===--------------------------------------------------------------------===//
+  std::unique_ptr<RemarkEngine> remarkEngine;
+
   //===--------------------------------------------------------------------===//
   // Options
   //===--------------------------------------------------------------------===//
@@ -387,6 +394,34 @@ bool MLIRContext::hasActionHandler() { return (bool)getImpl().actionHandler; }
 /// Returns the diagnostic engine for this context.
 DiagnosticEngine &MLIRContext::getDiagEngine() { return getImpl().diagEngine; }
 
+//===----------------------------------------------------------------------===//
+// Remark Handlers
+//===----------------------------------------------------------------------===//
+
+/// Returns the remark engine for this context.
+void MLIRContext::setRemarkEngine(std::unique_ptr<RemarkEngine> engine) {
+  getImpl().remarkEngine = std::move(engine);
+}
+
+std::unique_ptr<RemarkEngine> &MLIRContext::getRemarkEngine() {
+  return getImpl().remarkEngine;
+}
+
+void MLIRContext::setupOptimizationRemarks(
+    StringRef outputPath, StringRef outputFormat, bool printAsEmitRemarks,
+    const std::optional<std::string> &categoryPassName,
+    const std::optional<std::string> &categoryMissName,
+    const std::optional<std::string> &categoryAnalysisName,
+    const std::optional<std::string> &categoryFailedName) {
+  auto engine = std::make_unique<RemarkEngine>(
+      printAsEmitRemarks, categoryPassName, categoryMissName,
+      categoryAnalysisName, categoryFailedName);
+  llvm::Error e = engine->initialize(outputPath, outputFormat);
+  if (e)
+    llvm::report_fatal_error("Failed to initialize remark engine");
+  setRemarkEngine(std::move(engine));
+}
+
 //===----------------------------------------------------------------------===//
 // Dialect and Operation Registration
 //===----------------------------------------------------------------------===//
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
new file mode 100644
index 0000000000000..4d2aa95236f68
--- /dev/null
+++ b/mlir/lib/IR/Remarks.cpp
@@ -0,0 +1,296 @@
+//===- Remarks.cpp - MLIR Remarks ---------------------------------===//
+//
+// 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/IR/Remarks.h"
+
+#include "mlir/IR/Attributes.h"
+#include "mlir/IR/BuiltinAttributes.h"
+#include "mlir/IR/Diagnostics.h"
+#include "mlir/IR/Value.h"
+
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/IR/LLVMRemarkStreamer.h"
+#include "llvm/Remarks/RemarkFormat.h"
+#include "llvm/Support/FileSystem.h"
+
+using namespace mlir;
+
+//------------------------------------------------------------------------------
+// RemarkBase
+//------------------------------------------------------------------------------
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, Value value)
+    : key(std::string(key)) {
+
+  llvm::raw_string_ostream rss(val);
+  rss << value;
+}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, Type type)
+    : key(std::string(key)) {
+  llvm::raw_string_ostream os(val);
+  os << type;
+}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, StringRef s)
+    : key(std::string(key)), val(s.str()) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, int n)
+    : key(std::string(key)), val(llvm::itostr(n)) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, float n)
+    : key(std::string(key)), val(std::to_string(n)) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, long n)
+    : key(std::string(key)), val(llvm::itostr(n)) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, long long n)
+    : key(std::string(key)), val(llvm::itostr(n)) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned n)
+    : key(std::string(key)), val(llvm::utostr(n)) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned long n)
+    : key(std::string(key)), val(llvm::utostr(n)) {}
+
+RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned long long n)
+    : key(std::string(key)), val(llvm::utostr(n)) {}
+
+void RemarkBase::print(llvm::DiagnosticPrinter &dp) const {
+  std::string str;
+  llvm::raw_string_ostream os(str);
+  getLocation()->print(os);
+  os.flush();
+  dp << str << ": " << getMsg();
+}
+
+void RemarkBase::print() const { emitError(getLocation(), getMsg()); }
+
+void RemarkBase::insert(StringRef s) { args.emplace_back(s); }
+
+void RemarkBase::insert(RemarkKeyValue a) { args.push_back(std::move(a)); }
+
+void RemarkBase::insert(SetIsVerbose v) { isVerboseRemark = true; }
+
+std::string RemarkBase::getMsg() const {
+  std::string str;
+  llvm::raw_string_ostream rss(str);
+  for (const RemarkBase::RemarkKeyValue &arg :
+       llvm::make_range(args.begin(), args.end()))
+    rss << arg.val;
+  return str;
+}
+
+llvm::remarks::Type RemarkBase::getRemarkType() const {
+  switch (remarkKind) {
+  case RemarkKind::OptimizationRemarkUnknown:
+    return llvm::remarks::Type::Unknown;
+  case RemarkKind::OptimizationRemarkPass:
+    return llvm::remarks::Type::Passed;
+  case RemarkKind::OptimizationRemarkMissed:
+    return llvm::remarks::Type::Missed;
+  case RemarkKind::OptimizationRemarkFailure:
+    return llvm::remarks::Type::Failure;
+  case RemarkKind::OptimizationRemarkAnalysis:
+    return llvm::remarks::Type::Analysis;
+  }
+  llvm_unreachable("Unknown remark kind");
+}
+
+llvm::remarks::RemarkLocation RemarkBase::getRemarkLocation() const {
+  if (auto flc = dyn_cast<FileLineColLoc>(getLocation())) {
+    auto *buf = new std::string("./" + flc.getFilename().str());
+    return {*buf, flc.getLine(), flc.getColumn()};
+  }
+  return {"<unknown file>", 0, 0};
+}
+
+llvm::remarks::Remark RemarkBase::generateRemark() const {
+  llvm::remarks::Remark r; // The result.
+  r.RemarkType = getRemarkType();
+  r.PassName = getPassName();
+  r.RemarkName = getRemarkName();
+  r.FunctionName = getFunction();
+  r.Loc = getRemarkLocation();
+  for (const RemarkBase::RemarkKeyValue &arg : getArgs()) {
+    r.Args.emplace_back();
+    r.Args.back().Key = arg.key;
+    r.Args.back().Val = arg.val;
+  }
+  return r;
+}
+
+//===----------------------------------------------------------------------===//
+// InFlightRemark
+//===----------------------------------------------------------------------===//
+
+InFlightRemark::~InFlightRemark() {
+  if (remark)
+    if (owner) {
+      owner->report(std::move(*remark));
+    }
+  owner = nullptr;
+}
+
+//===----------------------------------------------------------------------===//
+// Remark Engine
+//===----------------------------------------------------------------------===//
+
+template <typename RemarkT, typename... Args>
+InFlightRemark RemarkEngine::makeRemark(Args &&...args) {
+  return InFlightRemark(*this, new RemarkT(std::forward<Args>(args)...));
+}
+
+template <typename RemarkT>
+InFlightRemark
+RemarkEngine::emitIfEnabled(Location loc, StringRef passName,
+                            StringRef category,
+                            bool (RemarkEngine::*isEnabled)(StringRef) const) {
+  return (this->*isEnabled)(category)
+             ? makeRemark<RemarkT>(loc, category, passName)
+             : InFlightRemark{};
+}
+
+bool RemarkEngine::isMissedOptRemarkEnabled(StringRef categoryName) const {
+  return missFilter && missFilter->match(categoryName);
+}
+
+bool RemarkEngine::isPassedOptRemarkEnabled(StringRef categoryName) const {
+  return passFilter && passFilter->match(categoryName);
+}
+
+bool RemarkEngine::isAnalysisOptRemarkEnabled(StringRef categoryName) const {
+  return analysisFilter && analysisFilter->match(categoryName);
+}
+
+bool RemarkEngine::isFailedOptRemarkEnabled(StringRef categoryName) const {
+  return failedFilter && failedFilter->match(categoryName);
+}
+
+InFlightRemark RemarkEngine::emitOptimizationRemark(Location loc,
+                                                    StringRef passName,
+                                                    StringRef category) {
+  return emitIfEnabled<OptRemarkPass>(loc, passName, category,
+                                      &RemarkEngine::isPassedOptRemarkEnabled);
+}
+
+InFlightRemark RemarkEngine::emitOptimizationRemarkMiss(Location loc,
+                                                        StringRef passName,
+                                                        StringRef category) {
+  return emitIfEnabled<OptRemarkMissed>(
+      loc, passName, category, &RemarkEngine::isMissedOptRemarkEnabled);
+}
+
+InFlightRemark RemarkEngine::emitOptimizationRemarkFailure(Location loc,
+                                                           StringRef passName,
+                                                           StringRef category) {
+  return emitIfEnabled<OptRemarkFailure>(
+      loc, passName, category, &RemarkEngine::isFailedOptRemarkEnabled);
+}
+
+InFlightRemark
+RemarkEngine::emitOptimizationRemarkAnalysis(Location loc, StringRef passName,
+                                             StringRef category) {
+  return emitIfEnabled<OptRemarkAnalysis>(
+      loc, passName, category, &RemarkEngine::isAnalysisOptRemarkEnabled);
+}
+
+//===----------------------------------------------------------------------===//
+// RemarkStreamer
+//===----------------------------------------------------------------------===//
+void MLIRRemarkStreamer::streamOptimizationRemark(const RemarkBase &remark) {
+  if (!remarkStreamer.matchesFilter(remark.getPassName()))
+    return;
+
+  // First, convert the diagnostic to a remark.
+  llvm::remarks::Remark r = remark.generateRemark();
+  // Then, emit the remark through the serializer.
+  remarkStreamer.getSerializer().emit(r);
+}
+//===----------------------------------------------------------------------===//
+// Remarkengine
+//===----------------------------------------------------------------------===//
+
+void RemarkEngine::report(const RemarkBase &&diag) {
+  // Stream the remark
+  if (getLLVMRemarkStreamer() && remarksFile)
+    getLLVMRemarkStreamer()->streamOptimizationRemark(diag);
+
+  // Print using MLIR's diagnostic
+  if (printAsEmitRemarks) {
+    emitRemark(diag.getLocation(), diag.getMsg());
+  }
+}
+
+RemarkEngine::~RemarkEngine() {
+  if (remarksFile) {
+    remarksFile->keep();
+    remarksFile.reset();
+  }
+  setMainRemarkStreamer(nullptr);
+  setLLVMRemarkStreamer(nullptr);
+}
+
+llvm::Error RemarkEngine::initialize(StringRef outputPath,
+                                     StringRef outputFormat) {
+  if (remarksFile) {
+    return llvm::createStringError(
+        llvm::inconvertibleErrorCode(),
+        "RemarkEngine is already initialized with an output file");
+  }
+
+  auto fFormatOrErr = llvm::remarks::parseFormat(outputFormat);
+  if (!fFormatOrErr) {
+    return fFormatOrErr.takeError();
+  }
+  llvm::remarks::Format fFormat = *fFormatOrErr;
+  std::error_code errCode;
+  llvm::sys::fs::OpenFlags fFlags = (fFormat == llvm::remarks::Format::YAML)
+                                        ? llvm::sys::fs::OF_Text
+                                        : llvm::sys::fs::OF_None;
+
+  remarksFile =
+      std::make_unique<llvm::ToolOutputFile>(outputPath, errCode, fFlags);
+  if (errCode) {
+    remarksFile.reset(); // force an empty optional
+    return llvm::createStringError(errCode, "Failed to open remarks file");
+  }
+
+  auto remarkSerializer = llvm::remarks::createRemarkSerializer(
+      *fFormatOrErr, llvm::remarks::SerializerMode::Separate,
+      remarksFile->os());
+  if (llvm::Error err = remarkSerializer.takeError()) {
+    return err;
+  }
+
+  // Create the main remark streamer.
+  setMainRemarkStreamer(std::make_unique<llvm::remarks::RemarkStreamer>(
+      std::move(*remarkSerializer), outputFormat));
+
+  setLLVMRemarkStreamer(
+      std::make_unique<MLIRRemarkStreamer>(*getMainRemarkStreamer()));
+
+  return llvm::ErrorSuccess();
+}
+
+RemarkEngine::RemarkEngine(bool printAsEmitRemarks,
+                           std::optional<std::string> categoryPassName,
+                           std::optional<std::string> categoryMissName,
+                           std::optional<std::string> categoryAnalysisName,
+                           std::optional<std::string> categoryFailedName)
+    : printAsEmitRemarks(printAsEmitRemarks) {
+  if (categoryPassName)
+    passFilter = llvm::Regex(categoryPassName.value());
+  if (categoryMissName)
+    missFilter = llvm::Regex(categoryMissName.value());
+  if (categoryAnalysisName)
+    analysisFilter = llvm::Regex(categoryAnalysisName.value());
+  if (categoryFailedName)
+    failedFilter = llvm::Regex(categoryFailedName.value());
+}
diff --git a/mlir/unittests/IR/CMakeLists.txt b/mlir/unittests/IR/CMakeLists.txt
index a46e64718dab9..07b242f7440bb 100644
--- a/mlir/unittests/IR/CMakeLists.txt
+++ b/mlir/unittests/IR/CMakeLists.txt
@@ -14,6 +14,7 @@ add_mlir_unittest(MLIRIRTests
   MemrefLayoutTest.cpp
   OperationSupportTest.cpp
   PatternMatchTest.cpp
+  RemarkTest.cpp
   ShapedTypeTest.cpp
   SymbolTableTest.cpp
   TypeTest.cpp
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
new file mode 100644
index 0000000000000..8abddb44fd428
--- /dev/null
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -0,0 +1,106 @@
+//===- RemarkTest.cpp - Remark unit tests -------------------------------===//
+//
+// 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/IR/Diagnostics.h"
+#include "mlir/IR/Remarks.h"
+#include "mlir/Support/TypeID.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/YAMLParser.h"
+#include "gtest/gtest.h"
+#include <optional>
+
+using namespace llvm;
+using namespace mlir;
+using namespace mlir::detail;
+
+namespace {
+
+TEST(Remark, TestOutputOptimizationRemark) {
+  const auto *pass1Msg = "My message";
+  const auto *pass2Msg = "My another message";
+  const auto *pass3Msg = "Do not show this message";
+
+  auto *context = new MLIRContext();
+
+  std::string categoryLoopunroll("LoopUnroll");
+  std::string categoryInline("Inliner");
+  std::string myPassname1("myPass1");
+  std::string myPassname2("myPass2");
+  std::string funcName("myFunc");
+  std::string yamlFile = "/tmp/remarks.yaml";
+
+  Location loc = UnknownLoc::get(context);
+
+  // Setup the remark engine
+  context->setupOptimizationRemarks(yamlFile, "yaml", true, categoryLoopunroll,
+                                    std::nullopt, std::nullopt,
+                                    categoryLoopunroll);
+
+  // Remark 1: pass, category LoopUnroll
+  reportOptimizationPass(loc, categoryLoopunroll, myPassname1) << pass1Msg;
+  // Remark 2: failure, category LoopUnroll
+  reportOptimizationFail(loc, categoryLoopunroll, myPassname2) << pass2Msg;
+  // Remark 3: pass, category Inline (should not be printed)
+  reportOptimizationPass(loc, categoryInline, myPassname1) << pass3Msg;
+
+  delete context;
+
+  // Read the file
+  auto bufferOrErr = MemoryBuffer::getFile(yamlFile);
+  ASSERT_TRUE(static_cast<bool>(bufferOrErr)) << "Failed to open remarks file";
+  std::string content = bufferOrErr.get()->getBuffer().str();
+
+  // Remark 1: pass, should be printed
+  EXPECT_NE(content.find("--- !Passed"), std::string::npos);
+  EXPECT_NE(content.find("Pass:            " + categoryLoopunroll),
+            std::string::npos);
+  EXPECT_NE(content.find("Name:            " + myPassname1), std::string::npos);
+  EXPECT_NE(content.find("String:          " + std::string(pass1Msg)),
+            std::string::npos);
+
+  // Remark 2: failure, should be printed
+  EXPECT_NE(content.find("--- !Failure"), std::string::npos);
+  EXPECT_NE(content.find("Name:            " + myPassname2), std::string::npos);
+  EXPECT_NE(content.find("String:          " + std::string(pass2Msg)),
+            std::string::npos);
+
+  // Remark 3: pass, category Inline (should not be printed)
+  EXPECT_EQ(content.find("String:          " + std::string(pass3Msg)),
+            std::string::npos);
+}
+
+TEST(Remark, TestNoOutputOptimizationRemark) {
+  const auto *pass1Msg = "My message";
+
+  auto *context = new MLIRContext();
+
+  std::string categoryFailName("myImportantCategory");
+  std::string myPassname1("myPass1");
+  std::string funcName("myFunc");
+  std::string yamlFile = "/tmp/remarks.yaml";
+
+  std::error_code ec =
+      llvm::sys::fs::remove(yamlFile, /*IgnoreNonExisting=*/true);
+  if (ec) {
+    FAIL() << "Failed to remove file " << yamlFile << ": " << ec.message();
+  }
+
+  Location loc = UnknownLoc::get(context);
+  reportOptimizationFail(loc, categoryFailName, myPassname1) << pass1Msg;
+
+  delete context;
+
+  // No setup, so no output file should be created
+  // check!
+  bool fileExists = llvm::sys::fs::exists(yamlFile);
+  EXPECT_FALSE(fileExists)
+      << "Expected no YAML file to be created without setupOptimizationRemarks";
+}
+
+} // namespace

>From 066fe4730af59119d1d78853e6c7f31c3319e5ff Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Thu, 7 Aug 2025 11:19:47 +0000
Subject: [PATCH 02/22] address copilot

---
 mlir/include/mlir/IR/Remarks.h   |  1 -
 mlir/lib/IR/Remarks.cpp          | 16 +++++++---------
 mlir/unittests/IR/RemarkTest.cpp | 17 ++++++++++++-----
 3 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index 8f7e7a900e7f1..240857b388587 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -82,7 +82,6 @@ class RemarkBase : public llvm::DiagnosticInfo {
 
   virtual bool isEnabled() const = 0;
   Location getLocation() const { return loc; }
-  llvm::remarks::RemarkLocation getRemarkLocation() const;
   /// Diagnostic -> Remark
   llvm::remarks::Remark generateRemark() const;
 
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
index 4d2aa95236f68..c0bae3915f0e0 100644
--- a/mlir/lib/IR/Remarks.cpp
+++ b/mlir/lib/IR/Remarks.cpp
@@ -103,21 +103,19 @@ llvm::remarks::Type RemarkBase::getRemarkType() const {
   llvm_unreachable("Unknown remark kind");
 }
 
-llvm::remarks::RemarkLocation RemarkBase::getRemarkLocation() const {
-  if (auto flc = dyn_cast<FileLineColLoc>(getLocation())) {
-    auto *buf = new std::string("./" + flc.getFilename().str());
-    return {*buf, flc.getLine(), flc.getColumn()};
-  }
-  return {"<unknown file>", 0, 0};
-}
-
 llvm::remarks::Remark RemarkBase::generateRemark() const {
+  auto locLambda = [&]() -> llvm::remarks::RemarkLocation {
+    if (auto flc = dyn_cast<FileLineColLoc>(getLocation()))
+      return {flc.getFilename(), flc.getLine(), flc.getColumn()};
+    return {"<unknown file>", 0, 0};
+  };
+
   llvm::remarks::Remark r; // The result.
   r.RemarkType = getRemarkType();
   r.PassName = getPassName();
   r.RemarkName = getRemarkName();
   r.FunctionName = getFunction();
-  r.Loc = getRemarkLocation();
+  r.Loc = locLambda();
   for (const RemarkBase::RemarkKeyValue &arg : getArgs()) {
     r.Args.emplace_back();
     r.Args.back().Key = arg.key;
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index 8abddb44fd428..91bb6d82a6920 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -33,8 +33,12 @@ TEST(Remark, TestOutputOptimizationRemark) {
   std::string myPassname1("myPass1");
   std::string myPassname2("myPass2");
   std::string funcName("myFunc");
-  std::string yamlFile = "/tmp/remarks.yaml";
-
+  SmallString<64> tmpPathStorage;
+  sys::fs::createUniquePath("remarks-%%%%%%.yaml", tmpPathStorage,
+                            /*MakeAbsolute=*/true);
+  std::string yamlFile =
+      std::string(tmpPathStorage.data(), tmpPathStorage.size());
+  ASSERT_FALSE(yamlFile.empty());
   Location loc = UnknownLoc::get(context);
 
   // Setup the remark engine
@@ -77,14 +81,17 @@ TEST(Remark, TestOutputOptimizationRemark) {
 
 TEST(Remark, TestNoOutputOptimizationRemark) {
   const auto *pass1Msg = "My message";
-
   auto *context = new MLIRContext();
 
   std::string categoryFailName("myImportantCategory");
   std::string myPassname1("myPass1");
   std::string funcName("myFunc");
-  std::string yamlFile = "/tmp/remarks.yaml";
-
+  SmallString<64> tmpPathStorage;
+  sys::fs::createUniquePath("remarks-%%%%%%.yaml", tmpPathStorage,
+                            /*MakeAbsolute=*/true);
+  std::string yamlFile =
+      std::string(tmpPathStorage.data(), tmpPathStorage.size());
+  ASSERT_FALSE(yamlFile.empty());
   std::error_code ec =
       llvm::sys::fs::remove(yamlFile, /*IgnoreNonExisting=*/true);
   if (ec) {

>From fa75d31ae90429b73a0701f820f8a165b85a7ba9 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Fri, 8 Aug 2025 12:37:27 +0000
Subject: [PATCH 03/22] add doc

---
 mlir/docs/Remarks.md | 91 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 mlir/docs/Remarks.md

diff --git a/mlir/docs/Remarks.md b/mlir/docs/Remarks.md
new file mode 100644
index 0000000000000..4885f66d00d05
--- /dev/null
+++ b/mlir/docs/Remarks.md
@@ -0,0 +1,91 @@
+# Remark Infrastructure
+
+[TOC]
+
+Optimization remarks are structured, machine- and human-readable notes emitted by passes to explain what was optimized, what was missed, and why. MLIR integrates LLVM’s **remarks** infrastructure to make these insights easy to produce and consume.
+
+**Key points**
+
+- **Opt-in**: Disabled by default. No cost unless enabled.
+- **Per-context**: Configured on `MLIRContext`.
+- **Formats**: YAML or LLVM remark bitstream.
+- **Kinds**: Pass, Missed, Failure, Analysis.
+- **API**: Lightweight stream interface (similar to diagnostics) with `<<`.
+
+## Enabling remarks
+
+Enable once per `MLIRContext` (e.g., in your tool, pass pipeline setup, or test):
+
+```c++
+#include "mlir/IR/MLIRContext.h"
+
+// Writes remarks to /tmp/remarks.yaml in YAML format and mirrors them to
+// the DiagnosticEngine as 'remark' diagnostics with the given category labels.
+context.setupOptimizationRemarks(
+    /*outputPath=*/"/tmp/remarks.yaml",
+    /*outputFormat=*/yaml,              // or "bitstream"
+    /*printAsEmitRemarks=*/true,
+    /*categoryPassName=*/"opt.pass",      // optional category labels for mirroring
+    /*categoryMissName=*/"opt.missed",
+    /*categoryAnalysisName=*/"opt.analysis",
+    /*categoryFailedName=*/"opt.failed");
+```
+
+### Emitting remarks from a pass
+
+The functions `reportOptimization*` return an in-flight remark object (like MLIR diagnostics). One can append strings and key–value pairs with <<. 
+
+```c++
+#include "mlir/IR/Remarks.h"
+
+using namespace mlir;
+
+LogicalResult MyPass::runOnOperation() {
+  Operation *op = getOperation();
+  Location loc = op->getLoc();
+
+  // PASS: something succeeded
+  reportOptimizationPass(loc, /*category=*/"vectorizer", /*passName=*/"MyPass")
+      << "vectorized loop with tripCount="
+      << RemarkBase::RemarkKeyValue("tripCount", 128);
+
+  // ANALYSIS: neutral insight
+  reportOptimizationAnalysis(loc, "unroll", "MyPass")
+      << "estimated cost: " << RemarkBase::RemarkKeyValue("cost", 42);
+
+  // MISSED: explain why + suggest a fix
+  reportOptimizationMiss(loc, "unroll", "MyPass",
+                         /*suggestion=*/"increase unroll factor to >=4")
+      << "not profitable at this size";
+
+  // FAILURE: action attempted but failed
+  if (failed(doThing(op))) {
+    reportOptimizationFail(loc, "pipeline", "MyPass")
+        << "failed due to unsupported pattern";
+    return failure();
+  }
+  return success();
+}
+```
+
+## Output formats
+
+#### YAML
+
+A typical remark serialized to YAML looks like following. It is Readable, easy to diff and grep.
+
+```yaml
+--- !Passed
+pass:            MyPass
+name:            vectorizer
+function:        myFunc
+loc:             myfile.mlir:12:3
+args:
+  - key:         tripCount
+    value:       128
+message:         "vectorized loop with tripCount=128"
+```
+
+#### Bitstream
+
+Compact binary format supported by LLVM’s remark tooling. Prefer this for large production runs or where existing infrastructure already understands LLVM remarks.

>From d7a3c03119e810e29511400865678b478b1fc593 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Fri, 8 Aug 2025 12:37:34 +0000
Subject: [PATCH 04/22] address comments

---
 mlir/include/mlir/IR/MLIRContext.h |  12 +--
 mlir/include/mlir/IR/Remarks.h     |  93 +++++++++---------------
 mlir/lib/IR/MLIRContext.cpp        |  21 +++---
 mlir/lib/IR/Remarks.cpp            | 113 ++++++++++++++---------------
 mlir/unittests/IR/RemarkTest.cpp   |  81 +++++++++++++++------
 5 files changed, 168 insertions(+), 152 deletions(-)

diff --git a/mlir/include/mlir/IR/MLIRContext.h b/mlir/include/mlir/IR/MLIRContext.h
index ab8f4aed3fc79..590d7492d9e79 100644
--- a/mlir/include/mlir/IR/MLIRContext.h
+++ b/mlir/include/mlir/IR/MLIRContext.h
@@ -12,6 +12,7 @@
 #include "mlir/Support/LLVM.h"
 #include "mlir/Support/TypeID.h"
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/Remarks/RemarkFormat.h"
 #include <functional>
 #include <memory>
 #include <vector>
@@ -214,7 +215,7 @@ class MLIRContext {
   DiagnosticEngine &getDiagEngine();
 
   /// Returns the remark engine for this context.
-  std::unique_ptr<RemarkEngine> &getRemarkEngine();
+  RemarkEngine *getRemarkEngine();
 
   /// Returns the storage uniquer used for creating affine constructs.
   StorageUniquer &getAffineUniquer();
@@ -249,11 +250,12 @@ class MLIRContext {
   /// (attributes, operations, types, etc.).
   llvm::hash_code getRegistryHash();
 
-  /// Set up optimization remarks for the context.
+  /// Setup optimization remarks for the context.
   void setupOptimizationRemarks(
-      StringRef outputPath, StringRef outputFormat, bool printAsEmitRemarks,
-      const std::optional<std::string> &categoryPassName = std::nullopt,
-      const std::optional<std::string> &categoryMissName = std::nullopt,
+      StringRef outputPath, llvm::remarks::Format outputFormat,
+      bool printAsEmitRemarks,
+      const std::optional<std::string> &categoryPassedName = std::nullopt,
+      const std::optional<std::string> &categoryMissedName = std::nullopt,
       const std::optional<std::string> &categoryAnalysisName = std::nullopt,
       const std::optional<std::string> &categoryFailedName = std::nullopt);
 
diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index 240857b388587..e84b095976c71 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -27,7 +27,7 @@ namespace mlir {
 /// Defines different remark kinds that can be used to categorize remarks.
 enum class RemarkKind {
   OptimizationRemarkUnknown = 0,
-  OptimizationRemarkPass,
+  OptimizationRemarkPassed,
   OptimizationRemarkMissed,
   OptimizationRemarkFailure,
   OptimizationRemarkAnalysis,
@@ -143,7 +143,7 @@ class RemarkBase : public llvm::DiagnosticInfo {
     switch (remarkKind) {
     case RemarkKind::OptimizationRemarkUnknown:
       return llvm::DiagnosticKind::DK_Generic;
-    case RemarkKind::OptimizationRemarkPass:
+    case RemarkKind::OptimizationRemarkPassed:
       return llvm::DiagnosticKind::DK_OptimizationRemark;
     case RemarkKind::OptimizationRemarkMissed:
       return llvm::DiagnosticKind::DK_OptimizationRemarkMissed;
@@ -156,51 +156,19 @@ class RemarkBase : public llvm::DiagnosticInfo {
   }
 };
 
-// clang-format off
-template <class RemarkT>
-decltype(auto) operator<<(
-    RemarkT &&r,
-    std::enable_if_t<std::is_base_of_v<RemarkBase,
-                                       std::remove_reference_t<RemarkT>>,
-                     StringRef>
-        s) {
+inline RemarkBase &operator<<(RemarkBase &r, StringRef s) {
   r.insert(s);
-  return std::forward<RemarkT>(r);
-}
-
-template <class RemarkT>
-decltype(auto) operator<<(
-    RemarkT &&r,
-    std::enable_if_t<std::is_base_of_v<RemarkBase,
-                                       std::remove_reference_t<RemarkT>>,
-                     RemarkBase::RemarkKeyValue>
-        a) {
-  r.insert(std::move(a));
-  return std::forward<RemarkT>(r);
+  return r;
 }
-
-template <class RemarkT>
-decltype(auto) operator<<(
-    RemarkT &&r,
-    std::enable_if_t<std::is_base_of_v<RemarkBase,
-                                       std::remove_reference_t<RemarkT>>,
-                     RemarkBase::SetIsVerbose>
-        v) {
-  r.insert(v);
-  return std::forward<RemarkT>(r);
+inline RemarkBase &&operator<<(RemarkBase &&r, StringRef s) {
+  r.insert(s);
+  return std::move(r);
 }
-
-template <class RemarkT>
-decltype(auto) operator<<(
-    RemarkT &&r,
-    std::enable_if_t<std::is_base_of_v<RemarkBase,
-                                       std::remove_reference_t<RemarkT>>,
-                     RemarkBase::SetExtraArgs>
-        ea) {
-  r.insert(ea);
-  return std::forward<RemarkT>(r);
+inline RemarkBase &operator<<(RemarkBase &r,
+                              const RemarkBase::RemarkKeyValue &kv) {
+  r.insert(kv);
+  return r;
 }
-// clang-format on
 
 //===----------------------------------------------------------------------===//
 // Shorthand aliases for different kinds of remarks.
@@ -209,8 +177,9 @@ decltype(auto) operator<<(
 template <RemarkKind K, DiagnosticSeverity S>
 class OptRemarkBase final : public RemarkBase {
 public:
-  explicit OptRemarkBase(Location loc, StringRef passName, StringRef remarkName)
-      : RemarkBase(K, S, passName.data(), remarkName, loc) {}
+  explicit OptRemarkBase(Location loc, StringRef passName,
+                         StringRef categoryName)
+      : RemarkBase(K, S, passName.data(), categoryName, loc) {}
 
   bool isEnabled() const override { return true; }
 };
@@ -218,7 +187,7 @@ class OptRemarkBase final : public RemarkBase {
 using OptRemarkAnalysis = OptRemarkBase<RemarkKind::OptimizationRemarkAnalysis,
                                         DiagnosticSeverity::Remark>;
 
-using OptRemarkPass = OptRemarkBase<RemarkKind::OptimizationRemarkPass,
+using OptRemarkPass = OptRemarkBase<RemarkKind::OptimizationRemarkPassed,
                                     DiagnosticSeverity::Remark>;
 
 using OptRemarkMissed = OptRemarkBase<RemarkKind::OptimizationRemarkMissed,
@@ -241,8 +210,8 @@ class RemarkEngine;
 class InFlightRemark {
 public:
   explicit InFlightRemark(RemarkBase *diag) : remark(diag) {}
-  InFlightRemark(RemarkEngine &eng, RemarkBase *diag)
-      : owner(&eng), remark(diag) {}
+  InFlightRemark(RemarkEngine &eng, std::unique_ptr<RemarkBase> diag)
+      : owner(&eng), remark(std::move(diag)) {}
 
   InFlightRemark() = default; // empty ctor
 
@@ -287,7 +256,8 @@ class MLIRRemarkStreamer {
 
 class RemarkEngine {
 private:
-  /// The category for missed optimization remarks.
+  /// Regex that filters missed optimization remarks: only matching one are
+  /// reported.
   std::optional<llvm::Regex> missFilter;
   /// The category for passed optimization remarks.
   std::optional<llvm::Regex> passFilter;
@@ -299,16 +269,17 @@ class RemarkEngine {
   std::unique_ptr<llvm::ToolOutputFile> remarksFile;
   /// The MLIR remark streamer that will be used to emit the remarks.
   std::unique_ptr<MLIRRemarkStreamer> remarkStreamer;
+  /// The LLVM remark streamer that will be used to emit the remarks.
   std::unique_ptr<llvm::remarks::RemarkStreamer> llvmRemarkStreamer;
   /// When is enabled, engine also prints remarks as mlir::emitRemarks.
-  bool printAsEmitRemarks;
+  bool printAsEmitRemarks = false;
+
   /// The main MLIR remark streamer that will be used to emit the remarks.
   MLIRRemarkStreamer *getLLVMRemarkStreamer() { return remarkStreamer.get(); }
   const MLIRRemarkStreamer *getLLVMRemarkStreamer() const {
     return remarkStreamer.get();
   }
-  void
-  setLLVMRemarkStreamer(std::unique_ptr<MLIRRemarkStreamer> remarkStreamer) {
+  void setRemarkStreamer(std::unique_ptr<MLIRRemarkStreamer> remarkStreamer) {
     this->remarkStreamer = std::move(remarkStreamer);
   }
 
@@ -361,8 +332,12 @@ class RemarkEngine {
                 bool (RemarkEngine::*isEnabled)(StringRef) const);
 
 public:
+  /// Default constructor is deleted, use the other constructor.
   RemarkEngine() = delete;
-  /// Constructs Remark engine with optional category names
+
+  /// Constructs Remark engine with optional category names. If a category
+  /// name is not provided, it is not enabled. The category names are used to
+  /// filter the remarks that are emitted.
   RemarkEngine(bool printAsEmitRemarks,
                std::optional<std::string> categoryPassName = std::nullopt,
                std::optional<std::string> categoryMissName = std::nullopt,
@@ -374,7 +349,8 @@ class RemarkEngine {
   ~RemarkEngine();
 
   /// Setup the remark engine with the given output path and format.
-  llvm::Error initialize(StringRef outputPath, StringRef outputFormat);
+  LogicalResult initialize(StringRef outputPath, llvm::remarks::Format fmt,
+                           std::string *errMsg);
 
   /// Report a diagnostic remark.
   void report(const RemarkBase &&diag);
@@ -406,14 +382,13 @@ using Suggestion = RemarkBase::RemarkKeyValue;
 inline Suggestion suggest(StringRef txt) { return {"Suggestion", txt}; }
 
 template <typename Fn, typename... Args>
-[[nodiscard]] inline InFlightRemark withEngine(Fn fn, Location loc,
-                                               Args &&...args) {
+inline InFlightRemark withEngine(Fn fn, Location loc, Args &&...args) {
   MLIRContext *ctx = loc->getContext();
 
-  auto &enginePtr = ctx->getRemarkEngine();
+  RemarkEngine *enginePtr = ctx->getRemarkEngine();
 
-  if (RemarkEngine *eng = enginePtr.get())
-    return (eng->*fn)(loc, std::forward<Args>(args)...);
+  if (enginePtr)
+    return (enginePtr->*fn)(loc, std::forward<Args>(args)...);
 
   return {};
 }
diff --git a/mlir/lib/IR/MLIRContext.cpp b/mlir/lib/IR/MLIRContext.cpp
index 5a37de1481eb9..3eb271d58a871 100644
--- a/mlir/lib/IR/MLIRContext.cpp
+++ b/mlir/lib/IR/MLIRContext.cpp
@@ -403,22 +403,25 @@ void MLIRContext::setRemarkEngine(std::unique_ptr<RemarkEngine> engine) {
   getImpl().remarkEngine = std::move(engine);
 }
 
-std::unique_ptr<RemarkEngine> &MLIRContext::getRemarkEngine() {
-  return getImpl().remarkEngine;
+RemarkEngine *MLIRContext::getRemarkEngine() {
+  return getImpl().remarkEngine.get();
 }
 
 void MLIRContext::setupOptimizationRemarks(
-    StringRef outputPath, StringRef outputFormat, bool printAsEmitRemarks,
-    const std::optional<std::string> &categoryPassName,
-    const std::optional<std::string> &categoryMissName,
+    StringRef outputPath, llvm::remarks::Format outputFormat,
+    bool printAsEmitRemarks,
+    const std::optional<std::string> &categoryPassedName,
+    const std::optional<std::string> &categoryMissedName,
     const std::optional<std::string> &categoryAnalysisName,
     const std::optional<std::string> &categoryFailedName) {
   auto engine = std::make_unique<RemarkEngine>(
-      printAsEmitRemarks, categoryPassName, categoryMissName,
+      printAsEmitRemarks, categoryPassedName, categoryMissedName,
       categoryAnalysisName, categoryFailedName);
-  llvm::Error e = engine->initialize(outputPath, outputFormat);
-  if (e)
-    llvm::report_fatal_error("Failed to initialize remark engine");
+  std::string errMsg;
+  if (failed(engine->initialize(outputPath, outputFormat, &errMsg))) {
+    llvm::report_fatal_error(
+        llvm::Twine("Failed to initialize remark engine. Error: ") + errMsg);
+  }
   setRemarkEngine(std::move(engine));
 }
 
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
index c0bae3915f0e0..f2d085d0b3357 100644
--- a/mlir/lib/IR/Remarks.cpp
+++ b/mlir/lib/IR/Remarks.cpp
@@ -84,14 +84,14 @@ std::string RemarkBase::getMsg() const {
   for (const RemarkBase::RemarkKeyValue &arg :
        llvm::make_range(args.begin(), args.end()))
     rss << arg.val;
-  return str;
+  return rss.str();
 }
 
 llvm::remarks::Type RemarkBase::getRemarkType() const {
   switch (remarkKind) {
   case RemarkKind::OptimizationRemarkUnknown:
     return llvm::remarks::Type::Unknown;
-  case RemarkKind::OptimizationRemarkPass:
+  case RemarkKind::OptimizationRemarkPassed:
     return llvm::remarks::Type::Passed;
   case RemarkKind::OptimizationRemarkMissed:
     return llvm::remarks::Type::Missed;
@@ -129,10 +129,8 @@ llvm::remarks::Remark RemarkBase::generateRemark() const {
 //===----------------------------------------------------------------------===//
 
 InFlightRemark::~InFlightRemark() {
-  if (remark)
-    if (owner) {
-      owner->report(std::move(*remark));
-    }
+  if (remark && owner)
+    owner->report(std::move(*remark));
   owner = nullptr;
 }
 
@@ -142,16 +140,19 @@ InFlightRemark::~InFlightRemark() {
 
 template <typename RemarkT, typename... Args>
 InFlightRemark RemarkEngine::makeRemark(Args &&...args) {
-  return InFlightRemark(*this, new RemarkT(std::forward<Args>(args)...));
+  static_assert(std::is_base_of_v<RemarkBase, RemarkT>,
+                "RemarkT must derive from RemarkBase");
+  return InFlightRemark(*this,
+                        std::make_unique<RemarkT>(std::forward<Args>(args)...));
 }
 
 template <typename RemarkT>
 InFlightRemark
 RemarkEngine::emitIfEnabled(Location loc, StringRef passName,
-                            StringRef category,
+                            StringRef categoryName,
                             bool (RemarkEngine::*isEnabled)(StringRef) const) {
-  return (this->*isEnabled)(category)
-             ? makeRemark<RemarkT>(loc, category, passName)
+  return (this->*isEnabled)(categoryName)
+             ? makeRemark<RemarkT>(loc, categoryName, passName)
              : InFlightRemark{};
 }
 
@@ -173,30 +174,30 @@ bool RemarkEngine::isFailedOptRemarkEnabled(StringRef categoryName) const {
 
 InFlightRemark RemarkEngine::emitOptimizationRemark(Location loc,
                                                     StringRef passName,
-                                                    StringRef category) {
-  return emitIfEnabled<OptRemarkPass>(loc, passName, category,
+                                                    StringRef categoryName) {
+  return emitIfEnabled<OptRemarkPass>(loc, passName, categoryName,
                                       &RemarkEngine::isPassedOptRemarkEnabled);
 }
 
-InFlightRemark RemarkEngine::emitOptimizationRemarkMiss(Location loc,
-                                                        StringRef passName,
-                                                        StringRef category) {
+InFlightRemark
+RemarkEngine::emitOptimizationRemarkMiss(Location loc, StringRef passName,
+                                         StringRef categoryName) {
   return emitIfEnabled<OptRemarkMissed>(
-      loc, passName, category, &RemarkEngine::isMissedOptRemarkEnabled);
+      loc, passName, categoryName, &RemarkEngine::isMissedOptRemarkEnabled);
 }
 
-InFlightRemark RemarkEngine::emitOptimizationRemarkFailure(Location loc,
-                                                           StringRef passName,
-                                                           StringRef category) {
+InFlightRemark
+RemarkEngine::emitOptimizationRemarkFailure(Location loc, StringRef passName,
+                                            StringRef categoryName) {
   return emitIfEnabled<OptRemarkFailure>(
-      loc, passName, category, &RemarkEngine::isFailedOptRemarkEnabled);
+      loc, passName, categoryName, &RemarkEngine::isFailedOptRemarkEnabled);
 }
 
 InFlightRemark
 RemarkEngine::emitOptimizationRemarkAnalysis(Location loc, StringRef passName,
-                                             StringRef category) {
+                                             StringRef categoryName) {
   return emitIfEnabled<OptRemarkAnalysis>(
-      loc, passName, category, &RemarkEngine::isAnalysisOptRemarkEnabled);
+      loc, passName, categoryName, &RemarkEngine::isAnalysisOptRemarkEnabled);
 }
 
 //===----------------------------------------------------------------------===//
@@ -221,9 +222,8 @@ void RemarkEngine::report(const RemarkBase &&diag) {
     getLLVMRemarkStreamer()->streamOptimizationRemark(diag);
 
   // Print using MLIR's diagnostic
-  if (printAsEmitRemarks) {
+  if (printAsEmitRemarks)
     emitRemark(diag.getLocation(), diag.getMsg());
-  }
 }
 
 RemarkEngine::~RemarkEngine() {
@@ -232,49 +232,46 @@ RemarkEngine::~RemarkEngine() {
     remarksFile.reset();
   }
   setMainRemarkStreamer(nullptr);
-  setLLVMRemarkStreamer(nullptr);
+  setRemarkStreamer(nullptr);
 }
 
-llvm::Error RemarkEngine::initialize(StringRef outputPath,
-                                     StringRef outputFormat) {
-  if (remarksFile) {
-    return llvm::createStringError(
-        llvm::inconvertibleErrorCode(),
-        "RemarkEngine is already initialized with an output file");
-  }
+LogicalResult RemarkEngine::initialize(StringRef outputPath,
+                                       llvm::remarks::Format fmt,
+                                       std::string *errMsg) {
+  auto fail = [&](llvm::StringRef msg) {
+    if (errMsg)
+      *errMsg = msg.str();
+    return failure();
+  };
 
-  auto fFormatOrErr = llvm::remarks::parseFormat(outputFormat);
-  if (!fFormatOrErr) {
-    return fFormatOrErr.takeError();
-  }
-  llvm::remarks::Format fFormat = *fFormatOrErr;
-  std::error_code errCode;
-  llvm::sys::fs::OpenFlags fFlags = (fFormat == llvm::remarks::Format::YAML)
-                                        ? llvm::sys::fs::OF_Text
-                                        : llvm::sys::fs::OF_None;
-
-  remarksFile =
-      std::make_unique<llvm::ToolOutputFile>(outputPath, errCode, fFlags);
-  if (errCode) {
-    remarksFile.reset(); // force an empty optional
-    return llvm::createStringError(errCode, "Failed to open remarks file");
+  if (remarksFile)
+    return fail("RemarkEngine is already initialized with an output file.");
+
+  llvm::sys::fs::OpenFlags flags = (fmt == llvm::remarks::Format::YAML)
+                                       ? llvm::sys::fs::OF_Text
+                                       : llvm::sys::fs::OF_None;
+  std::error_code ec;
+  remarksFile = std::make_unique<llvm::ToolOutputFile>(outputPath, ec, flags);
+
+  if (ec) {
+    remarksFile.reset();
+    return fail(
+        ("Failed to open remarks file '" + outputPath + "': " + ec.message())
+            .str());
   }
 
-  auto remarkSerializer = llvm::remarks::createRemarkSerializer(
-      *fFormatOrErr, llvm::remarks::SerializerMode::Separate,
-      remarksFile->os());
-  if (llvm::Error err = remarkSerializer.takeError()) {
-    return err;
+  auto serializer = llvm::remarks::createRemarkSerializer(
+      fmt, llvm::remarks::SerializerMode::Separate, remarksFile->os());
+  if (!serializer) {
+    remarksFile.reset();
+    return fail(llvm::toString(serializer.takeError()));
   }
 
-  // Create the main remark streamer.
   setMainRemarkStreamer(std::make_unique<llvm::remarks::RemarkStreamer>(
-      std::move(*remarkSerializer), outputFormat));
-
-  setLLVMRemarkStreamer(
+      std::move(*serializer), outputPath));
+  setRemarkStreamer(
       std::make_unique<MLIRRemarkStreamer>(*getMainRemarkStreamer()));
-
-  return llvm::ErrorSuccess();
+  return success();
 }
 
 RemarkEngine::RemarkEngine(bool printAsEmitRemarks,
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index 91bb6d82a6920..2472b140e07ac 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -10,6 +10,7 @@
 #include "mlir/IR/Remarks.h"
 #include "mlir/Support/TypeID.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Remarks/RemarkFormat.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/YAMLParser.h"
 #include "gtest/gtest.h"
@@ -26,8 +27,6 @@ TEST(Remark, TestOutputOptimizationRemark) {
   const auto *pass2Msg = "My another message";
   const auto *pass3Msg = "Do not show this message";
 
-  auto *context = new MLIRContext();
-
   std::string categoryLoopunroll("LoopUnroll");
   std::string categoryInline("Inliner");
   std::string myPassname1("myPass1");
@@ -39,21 +38,26 @@ TEST(Remark, TestOutputOptimizationRemark) {
   std::string yamlFile =
       std::string(tmpPathStorage.data(), tmpPathStorage.size());
   ASSERT_FALSE(yamlFile.empty());
-  Location loc = UnknownLoc::get(context);
 
-  // Setup the remark engine
-  context->setupOptimizationRemarks(yamlFile, "yaml", true, categoryLoopunroll,
-                                    std::nullopt, std::nullopt,
-                                    categoryLoopunroll);
+  {
+    MLIRContext context;
+    Location loc = UnknownLoc::get(&context);
 
-  // Remark 1: pass, category LoopUnroll
-  reportOptimizationPass(loc, categoryLoopunroll, myPassname1) << pass1Msg;
-  // Remark 2: failure, category LoopUnroll
-  reportOptimizationFail(loc, categoryLoopunroll, myPassname2) << pass2Msg;
-  // Remark 3: pass, category Inline (should not be printed)
-  reportOptimizationPass(loc, categoryInline, myPassname1) << pass3Msg;
+    context.printOpOnDiagnostic(true);
+    context.printStackTraceOnDiagnostic(true);
+
+    // Setup the remark engine
+    context.setupOptimizationRemarks(yamlFile, llvm::remarks::Format::YAML,
+                                     true, categoryLoopunroll, std::nullopt,
+                                     std::nullopt, categoryLoopunroll);
 
-  delete context;
+    // Remark 1: pass, category LoopUnroll
+    reportOptimizationPass(loc, categoryLoopunroll, myPassname1) << pass1Msg;
+    // Remark 2: failure, category LoopUnroll
+    reportOptimizationFail(loc, categoryLoopunroll, myPassname2) << pass2Msg;
+    // Remark 3: pass, category Inline (should not be printed)
+    reportOptimizationPass(loc, categoryInline, myPassname1) << pass3Msg;
+  }
 
   // Read the file
   auto bufferOrErr = MemoryBuffer::getFile(yamlFile);
@@ -81,7 +85,6 @@ TEST(Remark, TestOutputOptimizationRemark) {
 
 TEST(Remark, TestNoOutputOptimizationRemark) {
   const auto *pass1Msg = "My message";
-  auto *context = new MLIRContext();
 
   std::string categoryFailName("myImportantCategory");
   std::string myPassname1("myPass1");
@@ -97,12 +100,11 @@ TEST(Remark, TestNoOutputOptimizationRemark) {
   if (ec) {
     FAIL() << "Failed to remove file " << yamlFile << ": " << ec.message();
   }
-
-  Location loc = UnknownLoc::get(context);
-  reportOptimizationFail(loc, categoryFailName, myPassname1) << pass1Msg;
-
-  delete context;
-
+  {
+    MLIRContext context;
+    Location loc = UnknownLoc::get(&context);
+    reportOptimizationFail(loc, categoryFailName, myPassname1) << pass1Msg;
+  }
   // No setup, so no output file should be created
   // check!
   bool fileExists = llvm::sys::fs::exists(yamlFile);
@@ -110,4 +112,41 @@ TEST(Remark, TestNoOutputOptimizationRemark) {
       << "Expected no YAML file to be created without setupOptimizationRemarks";
 }
 
+TEST(Remark, TestOutputOptimizationRemarkDiagnostic) {
+  const auto *pass1Msg = "My message";
+
+  std::string categoryLoopunroll("LoopUnroll");
+  std::string myPassname1("myPass1");
+  std::string funcName("myFunc");
+  SmallString<64> tmpPathStorage;
+  sys::fs::createUniquePath("remarks-%%%%%%.yaml", tmpPathStorage,
+                            /*MakeAbsolute=*/true);
+  std::string yamlFile =
+      std::string(tmpPathStorage.data(), tmpPathStorage.size());
+  ASSERT_FALSE(yamlFile.empty());
+  std::string seenMsg;
+  {
+    MLIRContext context;
+    Location loc = UnknownLoc::get(&context);
+
+    context.printOpOnDiagnostic(true);
+    context.printStackTraceOnDiagnostic(true);
+
+    // Register a handler that captures the diagnostic.
+    ScopedDiagnosticHandler handler(&context, [&](Diagnostic &diag) {
+      seenMsg = diag.str();
+      return success();
+    });
+
+    // Setup the remark engine
+    context.setupOptimizationRemarks(yamlFile, llvm::remarks::Format::YAML,
+                                     true, categoryLoopunroll, std::nullopt,
+                                     std::nullopt, categoryLoopunroll);
+
+    // Remark 1: pass, category LoopUnroll
+    reportOptimizationPass(loc, categoryLoopunroll, myPassname1) << pass1Msg;
+  }
+  EXPECT_EQ(seenMsg, pass1Msg);
+}
+
 } // namespace

>From f22137f090387610d1f849ca1e58bd5926b52926 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Mon, 11 Aug 2025 11:49:37 +0000
Subject: [PATCH 05/22] Split Streamer from RemarlEngine

---
 mlir/include/mlir/IR/MLIRContext.h        |  23 +++-
 mlir/include/mlir/IR/Remarks.h            |  88 ++++--------
 mlir/include/mlir/Remark/RemarkStreamer.h |  33 +++++
 mlir/lib/CMakeLists.txt                   |   1 +
 mlir/lib/IR/CMakeLists.txt                |   5 -
 mlir/lib/IR/MLIRContext.cpp               |  18 +--
 mlir/lib/IR/Remarks.cpp                   | 161 ++++++++++------------
 mlir/lib/Remark/CMakeLists.txt            |  14 ++
 mlir/lib/Remark/RemarkStreamer.cpp        |  66 +++++++++
 mlir/unittests/IR/CMakeLists.txt          |   1 +
 mlir/unittests/IR/RemarkTest.cpp          | 103 ++++++++++++--
 11 files changed, 324 insertions(+), 189 deletions(-)
 create mode 100644 mlir/include/mlir/Remark/RemarkStreamer.h
 create mode 100644 mlir/lib/Remark/CMakeLists.txt
 create mode 100644 mlir/lib/Remark/RemarkStreamer.cpp

diff --git a/mlir/include/mlir/IR/MLIRContext.h b/mlir/include/mlir/IR/MLIRContext.h
index 590d7492d9e79..cfb408b1f13eb 100644
--- a/mlir/include/mlir/IR/MLIRContext.h
+++ b/mlir/include/mlir/IR/MLIRContext.h
@@ -33,6 +33,7 @@ class InFlightDiagnostic;
 class Location;
 class MLIRContextImpl;
 class RegisteredOperationName;
+class MLIRRemarkStreamerBase;
 class RemarkEngine;
 class StorageUniquer;
 class IRUnit;
@@ -62,6 +63,10 @@ class IRUnit;
 class MLIRContext {
 public:
   enum class Threading { DISABLED, ENABLED };
+  struct RemarkCategories {
+    std::optional<std::string> passed, missed, analysis, failed;
+  };
+
   /// Create a new Context.
   explicit MLIRContext(Threading multithreading = Threading::ENABLED);
   explicit MLIRContext(const DialectRegistry &registry,
@@ -251,13 +256,17 @@ class MLIRContext {
   llvm::hash_code getRegistryHash();
 
   /// Setup optimization remarks for the context.
-  void setupOptimizationRemarks(
-      StringRef outputPath, llvm::remarks::Format outputFormat,
-      bool printAsEmitRemarks,
-      const std::optional<std::string> &categoryPassedName = std::nullopt,
-      const std::optional<std::string> &categoryMissedName = std::nullopt,
-      const std::optional<std::string> &categoryAnalysisName = std::nullopt,
-      const std::optional<std::string> &categoryFailedName = std::nullopt);
+  /// This will enable the remark engine and set the streamer to be used for
+  /// optimization remarks.
+  /// The remark categories are used to filter the remarks that will be emitted
+  /// by the remark engine. If a category is not specified, it will not be
+  /// emitted.
+  /// If `printAsEmitRemarks` is true, the remarks will be printed as
+  /// mlir::emitRemarks.
+  LogicalResult
+  enableOptimizationRemarks(std::unique_ptr<MLIRRemarkStreamerBase> streamer,
+                            const RemarkCategories &cats,
+                            bool printAsEmitRemarks = false);
 
   //===--------------------------------------------------------------------===//
   // Action API
diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index e84b095976c71..ccc2b79e1d05a 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -14,9 +14,8 @@
 #define MLIR_IR_REMARKS_H
 
 #include "llvm/IR/DiagnosticInfo.h"
-#include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/Remarks/Remark.h"
-#include "llvm/Remarks/RemarkStreamer.h"
+#include "llvm/Support/Regex.h"
 #include "llvm/Support/ToolOutputFile.h"
 
 #include "mlir/IR/Diagnostics.h"
@@ -36,21 +35,15 @@ enum class RemarkKind {
 //===----------------------------------------------------------------------===//
 // Remark Base Class
 //===----------------------------------------------------------------------===//
-class RemarkBase : public llvm::DiagnosticInfo {
+class RemarkBase {
 
 public:
   RemarkBase(RemarkKind remarkKind, DiagnosticSeverity severity,
              const char *passName, StringRef remarkName, Location loc,
              std::optional<StringRef> functionName = std::nullopt)
-      : llvm::DiagnosticInfo(makeLLVMKind(remarkKind),
-                             makeLLVMSeverity(severity)),
-        remarkKind(remarkKind), functionName(functionName), loc(loc),
+      : remarkKind(remarkKind), functionName(functionName), loc(loc),
         passName(passName), remarkName(remarkName) {}
 
-  struct SetIsVerbose {};
-
-  struct SetExtraArgs {};
-
   struct RemarkKeyValue {
     std::string key;
     std::string val;
@@ -74,13 +67,9 @@ class RemarkBase : public llvm::DiagnosticInfo {
 
   void insert(StringRef s);
   void insert(RemarkKeyValue a);
-  void insert(SetIsVerbose v);
-  void insert(SetExtraArgs ea);
 
-  void print(llvm::DiagnosticPrinter &dp) const override;
-  void print() const;
+  void print(llvm::raw_ostream &os, bool printLocation = false) const;
 
-  virtual bool isEnabled() const = 0;
   Location getLocation() const { return loc; }
   /// Diagnostic -> Remark
   llvm::remarks::Remark generateRemark() const;
@@ -94,12 +83,12 @@ class RemarkBase : public llvm::DiagnosticInfo {
   StringRef getRemarkName() const { return remarkName; }
   std::string getMsg() const;
 
-  bool isVerbose() const { return isVerboseRemark; }
-
   ArrayRef<RemarkKeyValue> getArgs() const { return args; }
 
   llvm::remarks::Type getRemarkType() const;
 
+  std::string getRemarkTypeString() const;
+
 protected:
   /// Keeps the MLIR diagnostic kind, which is used to determine the
   /// diagnostic kind in the LLVM remark streamer.
@@ -119,9 +108,6 @@ class RemarkBase : public llvm::DiagnosticInfo {
   /// RemarkKeyValues collected via the streaming interface.
   SmallVector<RemarkKeyValue, 4> args;
 
-  /// The remark is expected to be noisy.
-  bool isVerboseRemark = false;
-
 private:
   /// Convert the MLIR diagnostic severity to LLVM diagnostic severity.
   static llvm::DiagnosticSeverity
@@ -180,8 +166,6 @@ class OptRemarkBase final : public RemarkBase {
   explicit OptRemarkBase(Location loc, StringRef passName,
                          StringRef categoryName)
       : RemarkBase(K, S, passName.data(), categoryName, loc) {}
-
-  bool isEnabled() const override { return true; }
 };
 
 using OptRemarkAnalysis = OptRemarkBase<RemarkKind::OptimizationRemarkAnalysis,
@@ -240,14 +224,21 @@ class InFlightRemark {
 // MLIR Remark Streamer
 //===----------------------------------------------------------------------===//
 
-class MLIRRemarkStreamer {
-  llvm::remarks::RemarkStreamer &remarkStreamer;
-
+/// Base class for MLIR remark streamers that is used to stream
+/// optimization remarks to the underlying remark streamer. The derived classes
+/// should implement the `streamOptimizationRemark` method to provide the
+/// actual streaming implementation.
+class MLIRRemarkStreamerBase {
 public:
-  explicit MLIRRemarkStreamer(llvm::remarks::RemarkStreamer &remarkStreamer)
-      : remarkStreamer(remarkStreamer) {}
-
-  void streamOptimizationRemark(const RemarkBase &remark);
+  virtual ~MLIRRemarkStreamerBase() = default;
+  /// Stream an optimization remark to the underlying remark streamer. It is
+  /// called by the RemarkEngine to stream the optimization remarks.
+  ///
+  /// It must be overridden by the derived classes to provide
+  /// the actual streaming implementation.
+  virtual void streamOptimizationRemark(const RemarkBase &remark) = 0;
+
+  virtual void finalize() {} // optional
 };
 
 //===----------------------------------------------------------------------===//
@@ -265,37 +256,11 @@ class RemarkEngine {
   std::optional<llvm::Regex> analysisFilter;
   /// The category for failed optimization remarks.
   std::optional<llvm::Regex> failedFilter;
-  /// The output file for the remarks.
-  std::unique_ptr<llvm::ToolOutputFile> remarksFile;
   /// The MLIR remark streamer that will be used to emit the remarks.
-  std::unique_ptr<MLIRRemarkStreamer> remarkStreamer;
-  /// The LLVM remark streamer that will be used to emit the remarks.
-  std::unique_ptr<llvm::remarks::RemarkStreamer> llvmRemarkStreamer;
+  std::unique_ptr<MLIRRemarkStreamerBase> remarkStreamer;
   /// When is enabled, engine also prints remarks as mlir::emitRemarks.
   bool printAsEmitRemarks = false;
 
-  /// The main MLIR remark streamer that will be used to emit the remarks.
-  MLIRRemarkStreamer *getLLVMRemarkStreamer() { return remarkStreamer.get(); }
-  const MLIRRemarkStreamer *getLLVMRemarkStreamer() const {
-    return remarkStreamer.get();
-  }
-  void setRemarkStreamer(std::unique_ptr<MLIRRemarkStreamer> remarkStreamer) {
-    this->remarkStreamer = std::move(remarkStreamer);
-  }
-
-  /// Get the main MLIR remark streamer that will be used to emit the remarks.
-  llvm::remarks::RemarkStreamer *getMainRemarkStreamer() {
-    return llvmRemarkStreamer.get();
-  }
-  const llvm::remarks::RemarkStreamer *getMainRemarkStreamer() const {
-    return llvmRemarkStreamer.get();
-  }
-  /// Set the main remark streamer to be used by the engine.
-  void setMainRemarkStreamer(
-      std::unique_ptr<llvm::remarks::RemarkStreamer> mainRemarkStreamer) {
-    llvmRemarkStreamer = std::move(mainRemarkStreamer);
-  }
-
   /// Return true if missed optimization remarks are enabled, override
   /// to provide different implementation.
   bool isMissedOptRemarkEnabled(StringRef categoryName) const;
@@ -339,21 +304,18 @@ class RemarkEngine {
   /// name is not provided, it is not enabled. The category names are used to
   /// filter the remarks that are emitted.
   RemarkEngine(bool printAsEmitRemarks,
-               std::optional<std::string> categoryPassName = std::nullopt,
-               std::optional<std::string> categoryMissName = std::nullopt,
-               std::optional<std::string> categoryAnalysisName = std::nullopt,
-               std::optional<std::string> categoryFailedName = std::nullopt);
+               const MLIRContext::RemarkCategories &cats);
 
   /// Destructor that will close the output file and reset the
   /// main remark streamer.
   ~RemarkEngine();
 
   /// Setup the remark engine with the given output path and format.
-  LogicalResult initialize(StringRef outputPath, llvm::remarks::Format fmt,
+  LogicalResult initialize(std::unique_ptr<MLIRRemarkStreamerBase> streamer,
                            std::string *errMsg);
 
-  /// Report a diagnostic remark.
-  void report(const RemarkBase &&diag);
+  /// Report a remark.
+  void report(const RemarkBase &&remark);
 
   /// Report a successful remark, this will create an InFlightRemark
   /// that can be used to build the remark using the << operator.
diff --git a/mlir/include/mlir/Remark/RemarkStreamer.h b/mlir/include/mlir/Remark/RemarkStreamer.h
new file mode 100644
index 0000000000000..649e8028fe737
--- /dev/null
+++ b/mlir/include/mlir/Remark/RemarkStreamer.h
@@ -0,0 +1,33 @@
+#include "mlir/IR/Remarks.h"
+#include "llvm/Remarks/RemarkStreamer.h"
+
+using namespace llvm;
+namespace mlir::remark {
+
+/// Concrete streamer that writes LLVM optimization remarks to a file
+/// (YAML or Bitstream). Lives outside core.
+class LLVMRemarkStreamer final : public MLIRRemarkStreamerBase {
+public:
+  static FailureOr<std::unique_ptr<MLIRRemarkStreamerBase>>
+  createToFile(llvm::StringRef path, llvm::remarks::Format fmt);
+
+  void streamOptimizationRemark(const RemarkBase &remark) override;
+  void finalize() override {}
+  ~LLVMRemarkStreamer() override;
+
+private:
+  LLVMRemarkStreamer() = default;
+
+  std::unique_ptr<class llvm::remarks::RemarkStreamer> remarkStreamer;
+  std::unique_ptr<class llvm::ToolOutputFile> file;
+};
+
+/// Enable optimization remarks to a file with the given path and format.
+/// The remark categories are used to filter the remarks that are emitted.
+/// If the printAsEmitRemarks flag is set, remarks will also be printed using
+/// mlir::emitRemarks.
+LogicalResult enableOptimizationRemarksToFile(
+    MLIRContext &ctx, StringRef path, llvm::remarks::Format fmt,
+    const MLIRContext::RemarkCategories &cat, bool printAsEmitRemarks = false);
+
+} // namespace mlir::remark
\ No newline at end of file
diff --git a/mlir/lib/CMakeLists.txt b/mlir/lib/CMakeLists.txt
index 191b5ab6a6f56..91ed05f6548d7 100644
--- a/mlir/lib/CMakeLists.txt
+++ b/mlir/lib/CMakeLists.txt
@@ -13,6 +13,7 @@ add_subdirectory(Parser)
 add_subdirectory(Pass)
 add_subdirectory(Query)
 add_subdirectory(Reducer)
+add_subdirectory(Remark)
 add_subdirectory(Rewrite)
 add_subdirectory(Support)
 add_subdirectory(TableGen)
diff --git a/mlir/lib/IR/CMakeLists.txt b/mlir/lib/IR/CMakeLists.txt
index 438e486f2ad4c..d95bdc957e3c2 100644
--- a/mlir/lib/IR/CMakeLists.txt
+++ b/mlir/lib/IR/CMakeLists.txt
@@ -70,10 +70,5 @@ add_mlir_library(MLIRIR
 
   LINK_LIBS PUBLIC
   MLIRSupport
-  
-  LINK_COMPONENTS
-    Remarks
-    Core
-    BitstreamReader  
   )
 
diff --git a/mlir/lib/IR/MLIRContext.cpp b/mlir/lib/IR/MLIRContext.cpp
index 3eb271d58a871..e71db084c4b81 100644
--- a/mlir/lib/IR/MLIRContext.cpp
+++ b/mlir/lib/IR/MLIRContext.cpp
@@ -407,22 +407,18 @@ RemarkEngine *MLIRContext::getRemarkEngine() {
   return getImpl().remarkEngine.get();
 }
 
-void MLIRContext::setupOptimizationRemarks(
-    StringRef outputPath, llvm::remarks::Format outputFormat,
-    bool printAsEmitRemarks,
-    const std::optional<std::string> &categoryPassedName,
-    const std::optional<std::string> &categoryMissedName,
-    const std::optional<std::string> &categoryAnalysisName,
-    const std::optional<std::string> &categoryFailedName) {
-  auto engine = std::make_unique<RemarkEngine>(
-      printAsEmitRemarks, categoryPassedName, categoryMissedName,
-      categoryAnalysisName, categoryFailedName);
+LogicalResult MLIRContext::enableOptimizationRemarks(
+    std::unique_ptr<MLIRRemarkStreamerBase> streamer,
+    const RemarkCategories &cats, bool printAsEmitRemarks) {
+  auto engine = std::make_unique<RemarkEngine>(printAsEmitRemarks, cats);
+
   std::string errMsg;
-  if (failed(engine->initialize(outputPath, outputFormat, &errMsg))) {
+  if (failed(engine->initialize(std::move(streamer), &errMsg))) {
     llvm::report_fatal_error(
         llvm::Twine("Failed to initialize remark engine. Error: ") + errMsg);
   }
   setRemarkEngine(std::move(engine));
+  return success();
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
index f2d085d0b3357..6090682f72138 100644
--- a/mlir/lib/IR/Remarks.cpp
+++ b/mlir/lib/IR/Remarks.cpp
@@ -8,15 +8,12 @@
 
 #include "mlir/IR/Remarks.h"
 
-#include "mlir/IR/Attributes.h"
 #include "mlir/IR/BuiltinAttributes.h"
 #include "mlir/IR/Diagnostics.h"
 #include "mlir/IR/Value.h"
 
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/IR/LLVMRemarkStreamer.h"
-#include "llvm/Remarks/RemarkFormat.h"
 #include "llvm/Support/FileSystem.h"
 
 using namespace mlir;
@@ -62,29 +59,65 @@ RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned long n)
 RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned long long n)
     : key(std::string(key)), val(llvm::utostr(n)) {}
 
-void RemarkBase::print(llvm::DiagnosticPrinter &dp) const {
-  std::string str;
-  llvm::raw_string_ostream os(str);
-  getLocation()->print(os);
-  os.flush();
-  dp << str << ": " << getMsg();
+void RemarkBase::insert(StringRef s) { args.emplace_back(s); }
+
+void RemarkBase::insert(RemarkKeyValue a) { args.push_back(std::move(a)); }
+
+// Simple helper to print key=val list.
+static void printArgs(llvm::raw_ostream &os,
+                      llvm::ArrayRef<RemarkBase::RemarkKeyValue> args) {
+  if (args.empty())
+    return;
+  os << " {\n";
+  for (size_t i = 0; i < args.size(); ++i) {
+    const auto &a = args[i];
+    os << a.key << "=" << a.val;
+    if (i + 1 < args.size())
+      os << ", ";
+    os << "\n";
+  }
+  os << "\n}";
 }
 
-void RemarkBase::print() const { emitError(getLocation(), getMsg()); }
+void RemarkBase::print(llvm::raw_ostream &os, bool printLocation) const {
+  os << getRemarkTypeString() << "\n";
+  os << getPassName() << ":" << getRemarkName() << "\n";
 
-void RemarkBase::insert(StringRef s) { args.emplace_back(s); }
+  // Function (if any)
+  if (!getFunction().empty())
+    os << " func=" << getFunction() << "\n";
 
-void RemarkBase::insert(RemarkKeyValue a) { args.push_back(std::move(a)); }
+  if (printLocation)
+    if (auto flc = mlir::dyn_cast<mlir::FileLineColLoc>(getLocation()))
+      os << " @" << flc.getFilename() << ":" << flc.getLine() << ":"
+         << flc.getColumn();
 
-void RemarkBase::insert(SetIsVerbose v) { isVerboseRemark = true; }
+  // Key/Value args
+  printArgs(os, getArgs());
+}
 
 std::string RemarkBase::getMsg() const {
-  std::string str;
-  llvm::raw_string_ostream rss(str);
-  for (const RemarkBase::RemarkKeyValue &arg :
-       llvm::make_range(args.begin(), args.end()))
-    rss << arg.val;
-  return rss.str();
+  std::string s;
+  llvm::raw_string_ostream os(s);
+  print(os);
+  os.flush();
+  return s;
+}
+
+std::string RemarkBase::getRemarkTypeString() const {
+  switch (remarkKind) {
+  case RemarkKind::OptimizationRemarkUnknown:
+    return "Unknown";
+  case RemarkKind::OptimizationRemarkPassed:
+    return "Passed";
+  case RemarkKind::OptimizationRemarkMissed:
+    return "Missed";
+  case RemarkKind::OptimizationRemarkFailure:
+    return "Failure";
+  case RemarkKind::OptimizationRemarkAnalysis:
+    return "Analysis";
+  }
+  llvm_unreachable("Unknown remark kind");
 }
 
 llvm::remarks::Type RemarkBase::getRemarkType() const {
@@ -200,92 +233,42 @@ RemarkEngine::emitOptimizationRemarkAnalysis(Location loc, StringRef passName,
       loc, passName, categoryName, &RemarkEngine::isAnalysisOptRemarkEnabled);
 }
 
-//===----------------------------------------------------------------------===//
-// RemarkStreamer
-//===----------------------------------------------------------------------===//
-void MLIRRemarkStreamer::streamOptimizationRemark(const RemarkBase &remark) {
-  if (!remarkStreamer.matchesFilter(remark.getPassName()))
-    return;
-
-  // First, convert the diagnostic to a remark.
-  llvm::remarks::Remark r = remark.generateRemark();
-  // Then, emit the remark through the serializer.
-  remarkStreamer.getSerializer().emit(r);
-}
 //===----------------------------------------------------------------------===//
 // Remarkengine
 //===----------------------------------------------------------------------===//
 
-void RemarkEngine::report(const RemarkBase &&diag) {
+void RemarkEngine::report(const RemarkBase &&remark) {
   // Stream the remark
-  if (getLLVMRemarkStreamer() && remarksFile)
-    getLLVMRemarkStreamer()->streamOptimizationRemark(diag);
+  if (remarkStreamer)
+    remarkStreamer->streamOptimizationRemark(remark);
 
   // Print using MLIR's diagnostic
   if (printAsEmitRemarks)
-    emitRemark(diag.getLocation(), diag.getMsg());
+    emitRemark(remark.getLocation(), remark.getMsg());
 }
 
 RemarkEngine::~RemarkEngine() {
-  if (remarksFile) {
-    remarksFile->keep();
-    remarksFile.reset();
-  }
-  setMainRemarkStreamer(nullptr);
-  setRemarkStreamer(nullptr);
+  if (remarkStreamer)
+    remarkStreamer->finalize();
 }
 
-LogicalResult RemarkEngine::initialize(StringRef outputPath,
-                                       llvm::remarks::Format fmt,
-                                       std::string *errMsg) {
-  auto fail = [&](llvm::StringRef msg) {
-    if (errMsg)
-      *errMsg = msg.str();
-    return failure();
-  };
-
-  if (remarksFile)
-    return fail("RemarkEngine is already initialized with an output file.");
-
-  llvm::sys::fs::OpenFlags flags = (fmt == llvm::remarks::Format::YAML)
-                                       ? llvm::sys::fs::OF_Text
-                                       : llvm::sys::fs::OF_None;
-  std::error_code ec;
-  remarksFile = std::make_unique<llvm::ToolOutputFile>(outputPath, ec, flags);
-
-  if (ec) {
-    remarksFile.reset();
-    return fail(
-        ("Failed to open remarks file '" + outputPath + "': " + ec.message())
-            .str());
-  }
-
-  auto serializer = llvm::remarks::createRemarkSerializer(
-      fmt, llvm::remarks::SerializerMode::Separate, remarksFile->os());
-  if (!serializer) {
-    remarksFile.reset();
-    return fail(llvm::toString(serializer.takeError()));
-  }
-
-  setMainRemarkStreamer(std::make_unique<llvm::remarks::RemarkStreamer>(
-      std::move(*serializer), outputPath));
-  setRemarkStreamer(
-      std::make_unique<MLIRRemarkStreamer>(*getMainRemarkStreamer()));
+LogicalResult
+RemarkEngine::initialize(std::unique_ptr<MLIRRemarkStreamerBase> streamer,
+                         std::string *errMsg) {
+  // If you need to validate categories/filters, do so here and set errMsg.
+  remarkStreamer = std::move(streamer);
   return success();
 }
 
 RemarkEngine::RemarkEngine(bool printAsEmitRemarks,
-                           std::optional<std::string> categoryPassName,
-                           std::optional<std::string> categoryMissName,
-                           std::optional<std::string> categoryAnalysisName,
-                           std::optional<std::string> categoryFailedName)
+                           const MLIRContext::RemarkCategories &cats)
     : printAsEmitRemarks(printAsEmitRemarks) {
-  if (categoryPassName)
-    passFilter = llvm::Regex(categoryPassName.value());
-  if (categoryMissName)
-    missFilter = llvm::Regex(categoryMissName.value());
-  if (categoryAnalysisName)
-    analysisFilter = llvm::Regex(categoryAnalysisName.value());
-  if (categoryFailedName)
-    failedFilter = llvm::Regex(categoryFailedName.value());
+  if (cats.passed)
+    passFilter = llvm::Regex(cats.passed.value());
+  if (cats.missed)
+    missFilter = llvm::Regex(cats.missed.value());
+  if (cats.analysis)
+    analysisFilter = llvm::Regex(cats.analysis.value());
+  if (cats.failed)
+    failedFilter = llvm::Regex(cats.failed.value());
 }
diff --git a/mlir/lib/Remark/CMakeLists.txt b/mlir/lib/Remark/CMakeLists.txt
new file mode 100644
index 0000000000000..4888d71a7ad66
--- /dev/null
+++ b/mlir/lib/Remark/CMakeLists.txt
@@ -0,0 +1,14 @@
+add_mlir_library(MLIRRemarkStreamer
+  RemarkStreamer.cpp
+
+  ADDITIONAL_HEADER_DIRS
+  ${MLIR_MAIN_INCLUDE_DIR}/mlir/Remark
+
+  LINK_LIBS PUBLIC
+    MLIRIR
+
+  LINK_COMPONENTS
+    Remarks
+    Core
+    BitstreamReader  
+  )
diff --git a/mlir/lib/Remark/RemarkStreamer.cpp b/mlir/lib/Remark/RemarkStreamer.cpp
new file mode 100644
index 0000000000000..be38b434dddc1
--- /dev/null
+++ b/mlir/lib/Remark/RemarkStreamer.cpp
@@ -0,0 +1,66 @@
+#include "mlir/Remark/RemarkStreamer.h"
+#include "mlir/IR/MLIRContext.h"
+#include "mlir/IR/Remarks.h"
+
+#include "llvm/Remarks/RemarkSerializer.h"
+#include "llvm/Remarks/RemarkStreamer.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/ToolOutputFile.h"
+
+namespace mlir::remark {
+
+FailureOr<std::unique_ptr<MLIRRemarkStreamerBase>>
+LLVMRemarkStreamer::createToFile(llvm::StringRef path,
+                                 llvm::remarks::Format fmt) {
+  std::error_code ec;
+  // Use error_code ctor; YAML is text. (Bitstream also works fine here.)
+  auto f =
+      std::make_unique<llvm::ToolOutputFile>(path, ec, llvm::sys::fs::OF_Text);
+  if (ec)
+    return failure();
+
+  auto serOr = llvm::remarks::createRemarkSerializer(
+      fmt, llvm::remarks::SerializerMode::Separate, f->os());
+  if (!serOr) {
+    llvm::consumeError(serOr.takeError());
+    return failure();
+  }
+
+  auto rs =
+      std::make_unique<llvm::remarks::RemarkStreamer>(std::move(*serOr), path);
+
+  auto impl = std::unique_ptr<LLVMRemarkStreamer>(new LLVMRemarkStreamer());
+  impl->remarkStreamer = std::move(rs);
+  impl->file = std::move(f);
+  return std::unique_ptr<MLIRRemarkStreamerBase>(std::move(impl));
+}
+
+void LLVMRemarkStreamer::streamOptimizationRemark(const RemarkBase &remark) {
+  if (!remarkStreamer->matchesFilter(remark.getPassName()))
+    return;
+
+  // First, convert the diagnostic to a remark.
+  llvm::remarks::Remark r = remark.generateRemark();
+  // Then, emit the remark through the serializer.
+  remarkStreamer->getSerializer().emit(r);
+}
+
+LLVMRemarkStreamer::~LLVMRemarkStreamer() {
+  if (file && remarkStreamer)
+    file->keep();
+}
+
+LogicalResult enableOptimizationRemarksToFile(
+    MLIRContext &ctx, StringRef path, llvm::remarks::Format fmt,
+    const MLIRContext::RemarkCategories &cat, bool printAsEmitRemarks) {
+
+  FailureOr<std::unique_ptr<MLIRRemarkStreamerBase>> sOr =
+      LLVMRemarkStreamer::createToFile(path, fmt);
+  if (failed(sOr))
+    return failure();
+  return ctx.enableOptimizationRemarks(std::move(*sOr), cat,
+                                       printAsEmitRemarks);
+}
+
+} // namespace mlir::remark
\ No newline at end of file
diff --git a/mlir/unittests/IR/CMakeLists.txt b/mlir/unittests/IR/CMakeLists.txt
index 07b242f7440bb..75cd2d65ef5a1 100644
--- a/mlir/unittests/IR/CMakeLists.txt
+++ b/mlir/unittests/IR/CMakeLists.txt
@@ -29,3 +29,4 @@ add_mlir_unittest(MLIRIRTests
 target_include_directories(MLIRIRTests PRIVATE "${MLIR_BINARY_DIR}/test/lib/Dialect/Test")
 mlir_target_link_libraries(MLIRIRTests PRIVATE MLIRIR)
 target_link_libraries(MLIRIRTests PRIVATE MLIRTestDialect)
+target_link_libraries(MLIRIRTests PRIVATE MLIRRemarkStreamer)
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index 2472b140e07ac..9b2087ca4d4cf 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -7,11 +7,15 @@
 //===----------------------------------------------------------------------===//
 
 #include "mlir/IR/Diagnostics.h"
+#include "mlir/IR/MLIRContext.h"
 #include "mlir/IR/Remarks.h"
+#include "mlir/Remark/RemarkStreamer.h"
 #include "mlir/Support/TypeID.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/IR/LLVMRemarkStreamer.h"
 #include "llvm/Remarks/RemarkFormat.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/LogicalResult.h"
 #include "llvm/Support/YAMLParser.h"
 #include "gtest/gtest.h"
 #include <optional>
@@ -47,9 +51,14 @@ TEST(Remark, TestOutputOptimizationRemark) {
     context.printStackTraceOnDiagnostic(true);
 
     // Setup the remark engine
-    context.setupOptimizationRemarks(yamlFile, llvm::remarks::Format::YAML,
-                                     true, categoryLoopunroll, std::nullopt,
-                                     std::nullopt, categoryLoopunroll);
+    mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryLoopunroll,
+                                             /*missed=*/std::nullopt,
+                                             /*analysis=*/std::nullopt,
+                                             /*failed=*/categoryLoopunroll};
+
+    LogicalResult isEnabled = mlir::remark::enableOptimizationRemarksToFile(
+        context, yamlFile, llvm::remarks::Format::YAML, cats);
+    ASSERT_TRUE(succeeded(isEnabled)) << "Failed to enable remark engine";
 
     // Remark 1: pass, category LoopUnroll
     reportOptimizationPass(loc, categoryLoopunroll, myPassname1) << pass1Msg;
@@ -118,13 +127,10 @@ TEST(Remark, TestOutputOptimizationRemarkDiagnostic) {
   std::string categoryLoopunroll("LoopUnroll");
   std::string myPassname1("myPass1");
   std::string funcName("myFunc");
-  SmallString<64> tmpPathStorage;
-  sys::fs::createUniquePath("remarks-%%%%%%.yaml", tmpPathStorage,
-                            /*MakeAbsolute=*/true);
-  std::string yamlFile =
-      std::string(tmpPathStorage.data(), tmpPathStorage.size());
-  ASSERT_FALSE(yamlFile.empty());
-  std::string seenMsg;
+
+  std::string seenMsg = "";
+  std::string expectedMsg = "Passed\nLoopUnroll:myPass1\n func=<unknown "
+                            "function>\n {\nString=My message\n\n}";
   {
     MLIRContext context;
     Location loc = UnknownLoc::get(&context);
@@ -139,14 +145,83 @@ TEST(Remark, TestOutputOptimizationRemarkDiagnostic) {
     });
 
     // Setup the remark engine
-    context.setupOptimizationRemarks(yamlFile, llvm::remarks::Format::YAML,
-                                     true, categoryLoopunroll, std::nullopt,
-                                     std::nullopt, categoryLoopunroll);
+    mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryLoopunroll,
+                                             /*missed=*/std::nullopt,
+                                             /*analysis=*/std::nullopt,
+                                             /*failed=*/categoryLoopunroll};
+
+    LogicalResult isEnabled =
+        context.enableOptimizationRemarks(nullptr, cats, true);
+    ASSERT_TRUE(succeeded(isEnabled)) << "Failed to enable remark engine";
 
     // Remark 1: pass, category LoopUnroll
     reportOptimizationPass(loc, categoryLoopunroll, myPassname1) << pass1Msg;
   }
-  EXPECT_EQ(seenMsg, pass1Msg);
+  EXPECT_EQ(seenMsg, expectedMsg);
 }
 
+/// Custom remark streamer that prints remarks to stderr.
+class MyCustomStreamer : public MLIRRemarkStreamerBase {
+public:
+  MyCustomStreamer() = default;
+
+  void streamOptimizationRemark(const RemarkBase &remark) override {
+    llvm::errs() << "Custom remark: ";
+    remark.print(llvm::errs(), true);
+    llvm::errs() << "\n";
+  }
+};
+
+TEST(Remark, TestCustomOptimizationRemarkDiagnostic) {
+  testing::internal::CaptureStderr();
+  const auto *pass1Msg = "My message";
+  const auto *pass2Msg = "My another message";
+  const auto *pass3Msg = "Do not show this message";
+
+  std::string categoryLoopunroll("LoopUnroll");
+  std::string categoryInline("Inliner");
+  std::string myPassname1("myPass1");
+  std::string myPassname2("myPass2");
+  std::string funcName("myFunc");
+
+  std::string seenMsg = "";
+
+  {
+    MLIRContext context;
+    Location loc = UnknownLoc::get(&context);
+
+    // Setup the remark engine
+    mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryLoopunroll,
+                                             /*missed=*/std::nullopt,
+                                             /*analysis=*/std::nullopt,
+                                             /*failed=*/categoryLoopunroll};
+
+    LogicalResult isEnabled = context.enableOptimizationRemarks(
+        std::make_unique<MyCustomStreamer>(), cats, true);
+    ASSERT_TRUE(succeeded(isEnabled)) << "Failed to enable remark engine";
+
+    // Remark 1: pass, category LoopUnroll
+    reportOptimizationPass(loc, categoryLoopunroll, myPassname1) << pass1Msg;
+    // Remark 2: failure, category LoopUnroll
+    reportOptimizationFail(loc, categoryLoopunroll, myPassname2) << pass2Msg;
+    // Remark 3: pass, category Inline (should not be printed)
+    reportOptimizationPass(loc, categoryInline, myPassname1) << pass3Msg;
+  }
+
+  llvm::errs().flush();
+  std::string errOut = ::testing::internal::GetCapturedStderr();
+
+  // Expect exactly two "Custom remark:" lines.
+  auto first = errOut.find("Custom remark:");
+  EXPECT_NE(first, std::string::npos);
+  auto second = errOut.find("Custom remark:", first + 1);
+  EXPECT_NE(second, std::string::npos);
+  auto third = errOut.find("Custom remark:", second + 1);
+  EXPECT_EQ(third, std::string::npos);
+
+  // Containment checks for messages.
+  EXPECT_NE(errOut.find(pass1Msg), std::string::npos); // printed
+  EXPECT_NE(errOut.find(pass2Msg), std::string::npos); // printed
+  EXPECT_EQ(errOut.find(pass3Msg), std::string::npos); // filtered out
+}
 } // namespace

>From 521c676919b75624fa549b698f1bb7cba159e935 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Mon, 11 Aug 2025 12:28:17 +0000
Subject: [PATCH 06/22] fix doc

---
 mlir/docs/Remarks.md | 107 +++++++++++++++++++++++++++++++++----------
 1 file changed, 83 insertions(+), 24 deletions(-)

diff --git a/mlir/docs/Remarks.md b/mlir/docs/Remarks.md
index 4885f66d00d05..8a92677e82b90 100644
--- a/mlir/docs/Remarks.md
+++ b/mlir/docs/Remarks.md
@@ -2,38 +2,75 @@
 
 [TOC]
 
-Optimization remarks are structured, machine- and human-readable notes emitted by passes to explain what was optimized, what was missed, and why. MLIR integrates LLVM’s **remarks** infrastructure to make these insights easy to produce and consume.
+Remarks are structured, human- and machine-readable notes emitted by passes to
+explain what was optimized, what was missed, and why. The `RemarkEngine`
+collects finalized remarks during compilation and forwards them to a pluggable
+streamer. A default streamer integrates LLVM’s `llvm::remarks` so you can stream
+while a pass runs and serialize to disk (YAML or LLVM bitstream) for tooling.
 
 **Key points**
 
-- **Opt-in**: Disabled by default. No cost unless enabled.
+- **Opt-in**: Disabled by default; zero overhead unless enabled.
 - **Per-context**: Configured on `MLIRContext`.
-- **Formats**: YAML or LLVM remark bitstream.
-- **Kinds**: Pass, Missed, Failure, Analysis.
-- **API**: Lightweight stream interface (similar to diagnostics) with `<<`.
+- **Formats**: Custom streamers, or LLVM’s Remark engine (YAML / Bitstream).
+- **Kinds**: `Pass`, `Missed`, `Failure`, `Analysis`.
+- **API**: Lightweight streaming interface with `<<` (similar to diagnostics).
 
-## Enabling remarks
+## How it works
 
-Enable once per `MLIRContext` (e.g., in your tool, pass pipeline setup, or test):
+Remarks has two important classes:
+
+- **`RemarkEngine`** (owned by `MLIRContext`): receives finalized
+  `InFlightRemark`s, optionally mirrors them to the `DiagnosticEngine`, then
+  dispatches to the installed streamer.
+- **`MLIRRemarkStreamerBase`** (abstract): backend interface with a single hook
+  `streamOptimizationRemark(const RemarkBase &)`.
+
+**Default backend – `MLIRLLVMRemarkStreamer`** Adapts `mlir::RemarkBase` to
+`llvm::remarks::Remark` and writes YAML/bitstream via
+`llvm::remarks::RemarkStreamer` to a `ToolOutputFile`.
+
+**Ownership**: `MLIRContext` → `RemarkEngine` → `MLIRRemarkStreamerBase`.
+
+## Enable Remarks via mlir::emitRemarks (No Streamer)
+
+Enable once per `MLIRContext` (e.g., where you build your pass pipeline or in
+your tool). If `printAsEmitRemarks` is true, each remark is also mirrored to the
+context’s `DiagnosticEngine` under the provided category labels—handy for
+interactive tools and tests.
+
+```c++
+mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryLoopunroll,
+                                          /*missed=*/std::nullopt,
+                                          /*analysis=*/std::nullopt,
+                                          /*failed=*/categoryLoopunroll};
+
+context.enableOptimizationRemarks(/*streamer=*/nullptr,
+                                  cats,
+                                  /*printAsEmitRemarks=*/true);
+```
+
+## Enable Remarks with LLVMRemarkStreamer (YAML/Bitstream)
+
+If you want to persist remarks to a file in YAML or bitstream format, use
+`mlir::remark::LLVMRemarkStreamer` (helper shown below):
 
 ```c++
-#include "mlir/IR/MLIRContext.h"
-
-// Writes remarks to /tmp/remarks.yaml in YAML format and mirrors them to
-// the DiagnosticEngine as 'remark' diagnostics with the given category labels.
-context.setupOptimizationRemarks(
-    /*outputPath=*/"/tmp/remarks.yaml",
-    /*outputFormat=*/yaml,              // or "bitstream"
-    /*printAsEmitRemarks=*/true,
-    /*categoryPassName=*/"opt.pass",      // optional category labels for mirroring
-    /*categoryMissName=*/"opt.missed",
-    /*categoryAnalysisName=*/"opt.analysis",
-    /*categoryFailedName=*/"opt.failed");
+#include "mlir/Remark/RemarkStreamer.h"
+
+mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryLoopunroll,
+                                         /*missed=*/std::nullopt,
+                                         /*analysis=*/std::nullopt,
+                                         /*failed=*/categoryLoopunroll};
+
+mlir::remark::enableOptimizationRemarksToFile(
+    context, yamlFile, llvm::remarks::Format::YAML, cats);
 ```
 
-### Emitting remarks from a pass
+## Emitting remarks from a pass
 
-The functions `reportOptimization*` return an in-flight remark object (like MLIR diagnostics). One can append strings and key–value pairs with <<. 
+The `reportOptimization*` functions return an in-flight remark object (like MLIR
+diagnostics). Append strings and key–value pairs with `<<`.
 
 ```c++
 #include "mlir/IR/Remarks.h"
@@ -68,11 +105,11 @@ LogicalResult MyPass::runOnOperation() {
 }
 ```
 
-## Output formats
+### Output formats
 
 #### YAML
 
-A typical remark serialized to YAML looks like following. It is Readable, easy to diff and grep.
+Readable, easy to diff and grep.
 
 ```yaml
 --- !Passed
@@ -88,4 +125,26 @@ message:         "vectorized loop with tripCount=128"
 
 #### Bitstream
 
-Compact binary format supported by LLVM’s remark tooling. Prefer this for large production runs or where existing infrastructure already understands LLVM remarks.
+Compact binary format supported by LLVM’s remark tooling. Prefer this for large
+production runs or when existing infrastructure already consumes LLVM remarks.
+
+## Enable Remarks with a Custom Streamer
+
+`RemarkEngine` talks to `MLIRRemarkStreamerBase`. Implement your own streamer to
+consume remarks in any format you like:
+
+```c++
+class MyStreamer : public MLIRRemarkStreamerBase {
+public:
+  void streamOptimizationRemark(const RemarkBase &remark) override {
+    // Convert RemarkBase to your format and write it out.
+  }
+};
+
+// ...
+auto myStreamer = std::make_unique<MyStreamer>();
+context.setupOptimizationRemarks(path,
+                                 std::move(myStreamer),
+                                 /*printAsEmitRemarks=*/false,
+                                 /*categories=*/cat);
+```

>From d851e0e9821207b455a75ce96af533584ac48bab Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Mon, 11 Aug 2025 14:54:34 +0000
Subject: [PATCH 07/22] add callback

---
 mlir/docs/Remarks.md           | 4 +++-
 mlir/include/mlir/IR/Remarks.h | 8 ++++----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/mlir/docs/Remarks.md b/mlir/docs/Remarks.md
index 8a92677e82b90..4b4498e7ea195 100644
--- a/mlir/docs/Remarks.md
+++ b/mlir/docs/Remarks.md
@@ -55,6 +55,8 @@ context.enableOptimizationRemarks(/*streamer=*/nullptr,
 If you want to persist remarks to a file in YAML or bitstream format, use
 `mlir::remark::LLVMRemarkStreamer` (helper shown below):
 
+You can read more information about [LLVM's Remark from here](https://llvm.org/docs/Remarks.html).
+
 ```c++
 #include "mlir/Remark/RemarkStreamer.h"
 
@@ -92,7 +94,7 @@ LogicalResult MyPass::runOnOperation() {
 
   // MISSED: explain why + suggest a fix
   reportOptimizationMiss(loc, "unroll", "MyPass",
-                         /*suggestion=*/"increase unroll factor to >=4")
+                         /*suggestion=*/[&](){ return "increase unroll factor to >=4"; })
       << "not profitable at this size";
 
   // FAILURE: action attempted but failed
diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index ccc2b79e1d05a..8ab4f037d21ef 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -362,13 +362,13 @@ inline InFlightRemark reportOptimizationPass(Location loc, StringRef cat,
 }
 
 /// Report an optimization remark that was missed.
-inline InFlightRemark reportOptimizationMiss(Location loc, StringRef cat,
-                                             StringRef passName,
-                                             StringRef suggestion) {
+inline InFlightRemark
+reportOptimizationMiss(Location loc, StringRef cat, StringRef passName,
+                       llvm::function_ref<std::string()> makeSuggestion) {
   auto r =
       withEngine(&RemarkEngine::emitOptimizationRemarkMiss, loc, passName, cat);
   if (r)
-    r << suggest(suggestion);
+    r << suggest(makeSuggestion());
   return r;
 }
 /// Report an optimization failure remark.

>From f4d7bd6433d817509f51a176e56fcab163766a56 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Mon, 11 Aug 2025 15:07:49 +0000
Subject: [PATCH 08/22] Add mlir::remark. RemarkBase->Remark

---
 mlir/docs/Remarks.md                      | 14 +++----
 mlir/include/mlir/IR/MLIRContext.h        | 18 ++++----
 mlir/include/mlir/IR/Remarks.h            | 40 +++++++++---------
 mlir/include/mlir/Remark/RemarkStreamer.h |  4 +-
 mlir/lib/IR/MLIRContext.cpp               | 12 +++---
 mlir/lib/IR/Remarks.cpp                   | 51 +++++++++++------------
 mlir/lib/Remark/RemarkStreamer.cpp        |  4 +-
 mlir/unittests/IR/RemarkTest.cpp          |  2 +-
 8 files changed, 73 insertions(+), 72 deletions(-)

diff --git a/mlir/docs/Remarks.md b/mlir/docs/Remarks.md
index 4b4498e7ea195..fe243ad30bcc5 100644
--- a/mlir/docs/Remarks.md
+++ b/mlir/docs/Remarks.md
@@ -24,9 +24,9 @@ Remarks has two important classes:
   `InFlightRemark`s, optionally mirrors them to the `DiagnosticEngine`, then
   dispatches to the installed streamer.
 - **`MLIRRemarkStreamerBase`** (abstract): backend interface with a single hook
-  `streamOptimizationRemark(const RemarkBase &)`.
+  `streamOptimizationRemark(const Remark &)`.
 
-**Default backend – `MLIRLLVMRemarkStreamer`** Adapts `mlir::RemarkBase` to
+**Default backend – `MLIRLLVMRemarkStreamer`** Adapts `mlir::Remark` to
 `llvm::remarks::Remark` and writes YAML/bitstream via
 `llvm::remarks::RemarkStreamer` to a `ToolOutputFile`.
 
@@ -85,12 +85,12 @@ LogicalResult MyPass::runOnOperation() {
 
   // PASS: something succeeded
   reportOptimizationPass(loc, /*category=*/"vectorizer", /*passName=*/"MyPass")
-      << "vectorized loop with tripCount="
-      << RemarkBase::RemarkKeyValue("tripCount", 128);
+      << "vectorized loop."
+      << Remark::RemarkKeyValue("tripCount", 128);
 
   // ANALYSIS: neutral insight
   reportOptimizationAnalysis(loc, "unroll", "MyPass")
-      << "estimated cost: " << RemarkBase::RemarkKeyValue("cost", 42);
+      << "estimated cost: " << Remark::RemarkKeyValue("cost", 42);
 
   // MISSED: explain why + suggest a fix
   reportOptimizationMiss(loc, "unroll", "MyPass",
@@ -138,8 +138,8 @@ consume remarks in any format you like:
 ```c++
 class MyStreamer : public MLIRRemarkStreamerBase {
 public:
-  void streamOptimizationRemark(const RemarkBase &remark) override {
-    // Convert RemarkBase to your format and write it out.
+  void streamOptimizationRemark(const Remark &remark) override {
+    // Convert Remark to your format and write it out.
   }
 };
 
diff --git a/mlir/include/mlir/IR/MLIRContext.h b/mlir/include/mlir/IR/MLIRContext.h
index cfb408b1f13eb..87786420de37d 100644
--- a/mlir/include/mlir/IR/MLIRContext.h
+++ b/mlir/include/mlir/IR/MLIRContext.h
@@ -12,7 +12,6 @@
 #include "mlir/Support/LLVM.h"
 #include "mlir/Support/TypeID.h"
 #include "llvm/ADT/ArrayRef.h"
-#include "llvm/Remarks/RemarkFormat.h"
 #include <functional>
 #include <memory>
 #include <vector>
@@ -33,10 +32,12 @@ class InFlightDiagnostic;
 class Location;
 class MLIRContextImpl;
 class RegisteredOperationName;
-class MLIRRemarkStreamerBase;
-class RemarkEngine;
 class StorageUniquer;
 class IRUnit;
+namespace remark {
+class MLIRRemarkStreamerBase;
+class RemarkEngine;
+} // namespace remark
 
 /// MLIRContext is the top-level object for a collection of MLIR operations. It
 /// holds immortal uniqued objects like types, and the tables used to unique
@@ -220,7 +221,7 @@ class MLIRContext {
   DiagnosticEngine &getDiagEngine();
 
   /// Returns the remark engine for this context.
-  RemarkEngine *getRemarkEngine();
+  remark::RemarkEngine *getRemarkEngine();
 
   /// Returns the storage uniquer used for creating affine constructs.
   StorageUniquer &getAffineUniquer();
@@ -263,10 +264,9 @@ class MLIRContext {
   /// emitted.
   /// If `printAsEmitRemarks` is true, the remarks will be printed as
   /// mlir::emitRemarks.
-  LogicalResult
-  enableOptimizationRemarks(std::unique_ptr<MLIRRemarkStreamerBase> streamer,
-                            const RemarkCategories &cats,
-                            bool printAsEmitRemarks = false);
+  LogicalResult enableOptimizationRemarks(
+      std::unique_ptr<remark::MLIRRemarkStreamerBase> streamer,
+      const RemarkCategories &cats, bool printAsEmitRemarks = false);
 
   //===--------------------------------------------------------------------===//
   // Action API
@@ -305,7 +305,7 @@ class MLIRContext {
 
 private:
   /// Set the remark engine for this context.
-  void setRemarkEngine(std::unique_ptr<RemarkEngine> engine);
+  void setRemarkEngine(std::unique_ptr<remark::RemarkEngine> engine);
 
   /// Return true if the given dialect is currently loading.
   bool isDialectLoading(StringRef dialectNamespace);
diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index 8ab4f037d21ef..7f8e10918dc04 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -16,12 +16,11 @@
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/Remarks/Remark.h"
 #include "llvm/Support/Regex.h"
-#include "llvm/Support/ToolOutputFile.h"
 
 #include "mlir/IR/Diagnostics.h"
 #include "mlir/IR/MLIRContext.h"
 
-namespace mlir {
+namespace mlir::remark {
 
 /// Defines different remark kinds that can be used to categorize remarks.
 enum class RemarkKind {
@@ -35,12 +34,12 @@ enum class RemarkKind {
 //===----------------------------------------------------------------------===//
 // Remark Base Class
 //===----------------------------------------------------------------------===//
-class RemarkBase {
+class Remark {
 
 public:
-  RemarkBase(RemarkKind remarkKind, DiagnosticSeverity severity,
-             const char *passName, StringRef remarkName, Location loc,
-             std::optional<StringRef> functionName = std::nullopt)
+  Remark(RemarkKind remarkKind, DiagnosticSeverity severity,
+         const char *passName, StringRef remarkName, Location loc,
+         std::optional<StringRef> functionName = std::nullopt)
       : remarkKind(remarkKind), functionName(functionName), loc(loc),
         passName(passName), remarkName(remarkName) {}
 
@@ -142,16 +141,15 @@ class RemarkBase {
   }
 };
 
-inline RemarkBase &operator<<(RemarkBase &r, StringRef s) {
+inline Remark &operator<<(Remark &r, StringRef s) {
   r.insert(s);
   return r;
 }
-inline RemarkBase &&operator<<(RemarkBase &&r, StringRef s) {
+inline Remark &&operator<<(Remark &&r, StringRef s) {
   r.insert(s);
   return std::move(r);
 }
-inline RemarkBase &operator<<(RemarkBase &r,
-                              const RemarkBase::RemarkKeyValue &kv) {
+inline Remark &operator<<(Remark &r, const Remark::RemarkKeyValue &kv) {
   r.insert(kv);
   return r;
 }
@@ -161,11 +159,11 @@ inline RemarkBase &operator<<(RemarkBase &r,
 //===----------------------------------------------------------------------===//
 
 template <RemarkKind K, DiagnosticSeverity S>
-class OptRemarkBase final : public RemarkBase {
+class OptRemarkBase final : public Remark {
 public:
   explicit OptRemarkBase(Location loc, StringRef passName,
                          StringRef categoryName)
-      : RemarkBase(K, S, passName.data(), categoryName, loc) {}
+      : Remark(K, S, passName.data(), categoryName, loc) {}
 };
 
 using OptRemarkAnalysis = OptRemarkBase<RemarkKind::OptimizationRemarkAnalysis,
@@ -186,15 +184,15 @@ class RemarkEngine;
 // InFlightRemark
 //===----------------------------------------------------------------------===//
 
-/// InFlightRemark is a RAII class that holds a reference to a RemarkBase
+/// InFlightRemark is a RAII class that holds a reference to a Remark
 /// instance and allows to build the remark using the << operator. The remark
 /// is emitted when the InFlightRemark instance is destroyed, which happens
 /// when the scope ends or when the InFlightRemark instance is moved.
 /// Similar to InFlightDiagnostic, but for remarks.
 class InFlightRemark {
 public:
-  explicit InFlightRemark(RemarkBase *diag) : remark(diag) {}
-  InFlightRemark(RemarkEngine &eng, std::unique_ptr<RemarkBase> diag)
+  explicit InFlightRemark(Remark *diag) : remark(diag) {}
+  InFlightRemark(RemarkEngine &eng, std::unique_ptr<Remark> diag)
       : owner(&eng), remark(std::move(diag)) {}
 
   InFlightRemark() = default; // empty ctor
@@ -217,7 +215,7 @@ class InFlightRemark {
 
 private:
   RemarkEngine *owner{nullptr};
-  std::unique_ptr<RemarkBase> remark;
+  std::unique_ptr<Remark> remark;
 };
 
 //===----------------------------------------------------------------------===//
@@ -236,7 +234,7 @@ class MLIRRemarkStreamerBase {
   ///
   /// It must be overridden by the derived classes to provide
   /// the actual streaming implementation.
-  virtual void streamOptimizationRemark(const RemarkBase &remark) = 0;
+  virtual void streamOptimizationRemark(const Remark &remark) = 0;
 
   virtual void finalize() {} // optional
 };
@@ -286,7 +284,7 @@ class RemarkEngine {
   }
 
   /// Emit a remark using the given maker function, which should return
-  /// a RemarkBase instance. The remark will be emitted using the main
+  /// a Remark instance. The remark will be emitted using the main
   /// remark streamer.
   template <typename RemarkT, typename... Args>
   InFlightRemark makeRemark(Args &&...args);
@@ -315,7 +313,7 @@ class RemarkEngine {
                            std::string *errMsg);
 
   /// Report a remark.
-  void report(const RemarkBase &&remark);
+  void report(const Remark &&remark);
 
   /// Report a successful remark, this will create an InFlightRemark
   /// that can be used to build the remark using the << operator.
@@ -340,7 +338,7 @@ class RemarkEngine {
 // Emitters
 //===----------------------------------------------------------------------===//
 
-using Suggestion = RemarkBase::RemarkKeyValue;
+using Suggestion = Remark::RemarkKeyValue;
 inline Suggestion suggest(StringRef txt) { return {"Suggestion", txt}; }
 
 template <typename Fn, typename... Args>
@@ -385,6 +383,6 @@ inline InFlightRemark reportOptimizationAnalysis(Location loc, StringRef cat,
                     passName, cat);
 }
 
-} // namespace mlir
+} // namespace mlir::remark
 
 #endif // MLIR_IR_REMARKS_H
\ No newline at end of file
diff --git a/mlir/include/mlir/Remark/RemarkStreamer.h b/mlir/include/mlir/Remark/RemarkStreamer.h
index 649e8028fe737..d985795ea4280 100644
--- a/mlir/include/mlir/Remark/RemarkStreamer.h
+++ b/mlir/include/mlir/Remark/RemarkStreamer.h
@@ -1,5 +1,7 @@
 #include "mlir/IR/Remarks.h"
+
 #include "llvm/Remarks/RemarkStreamer.h"
+#include "llvm/Support/ToolOutputFile.h"
 
 using namespace llvm;
 namespace mlir::remark {
@@ -11,7 +13,7 @@ class LLVMRemarkStreamer final : public MLIRRemarkStreamerBase {
   static FailureOr<std::unique_ptr<MLIRRemarkStreamerBase>>
   createToFile(llvm::StringRef path, llvm::remarks::Format fmt);
 
-  void streamOptimizationRemark(const RemarkBase &remark) override;
+  void streamOptimizationRemark(const Remark &remark) override;
   void finalize() override {}
   ~LLVMRemarkStreamer() override;
 
diff --git a/mlir/lib/IR/MLIRContext.cpp b/mlir/lib/IR/MLIRContext.cpp
index e71db084c4b81..55cbac4b2f570 100644
--- a/mlir/lib/IR/MLIRContext.cpp
+++ b/mlir/lib/IR/MLIRContext.cpp
@@ -138,7 +138,7 @@ class MLIRContextImpl {
   //===--------------------------------------------------------------------===//
   // Remark
   //===--------------------------------------------------------------------===//
-  std::unique_ptr<RemarkEngine> remarkEngine;
+  std::unique_ptr<remark::RemarkEngine> remarkEngine;
 
   //===--------------------------------------------------------------------===//
   // Options
@@ -399,18 +399,20 @@ DiagnosticEngine &MLIRContext::getDiagEngine() { return getImpl().diagEngine; }
 //===----------------------------------------------------------------------===//
 
 /// Returns the remark engine for this context.
-void MLIRContext::setRemarkEngine(std::unique_ptr<RemarkEngine> engine) {
+void MLIRContext::setRemarkEngine(
+    std::unique_ptr<remark::RemarkEngine> engine) {
   getImpl().remarkEngine = std::move(engine);
 }
 
-RemarkEngine *MLIRContext::getRemarkEngine() {
+remark::RemarkEngine *MLIRContext::getRemarkEngine() {
   return getImpl().remarkEngine.get();
 }
 
 LogicalResult MLIRContext::enableOptimizationRemarks(
-    std::unique_ptr<MLIRRemarkStreamerBase> streamer,
+    std::unique_ptr<remark::MLIRRemarkStreamerBase> streamer,
     const RemarkCategories &cats, bool printAsEmitRemarks) {
-  auto engine = std::make_unique<RemarkEngine>(printAsEmitRemarks, cats);
+  auto engine =
+      std::make_unique<remark::RemarkEngine>(printAsEmitRemarks, cats);
 
   std::string errMsg;
   if (failed(engine->initialize(std::move(streamer), &errMsg))) {
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
index 6090682f72138..6360960b851a1 100644
--- a/mlir/lib/IR/Remarks.cpp
+++ b/mlir/lib/IR/Remarks.cpp
@@ -14,58 +14,57 @@
 
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Support/FileSystem.h"
 
-using namespace mlir;
+using namespace mlir::remark;
 
 //------------------------------------------------------------------------------
-// RemarkBase
+// Remark
 //------------------------------------------------------------------------------
 
-RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, Value value)
+Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, Value value)
     : key(std::string(key)) {
 
   llvm::raw_string_ostream rss(val);
   rss << value;
 }
 
-RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, Type type)
+Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, Type type)
     : key(std::string(key)) {
   llvm::raw_string_ostream os(val);
   os << type;
 }
 
-RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, StringRef s)
+Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, StringRef s)
     : key(std::string(key)), val(s.str()) {}
 
-RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, int n)
+Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, int n)
     : key(std::string(key)), val(llvm::itostr(n)) {}
 
-RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, float n)
+Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, float n)
     : key(std::string(key)), val(std::to_string(n)) {}
 
-RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, long n)
+Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, long n)
     : key(std::string(key)), val(llvm::itostr(n)) {}
 
-RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, long long n)
+Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, long long n)
     : key(std::string(key)), val(llvm::itostr(n)) {}
 
-RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned n)
+Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned n)
     : key(std::string(key)), val(llvm::utostr(n)) {}
 
-RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned long n)
+Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned long n)
     : key(std::string(key)), val(llvm::utostr(n)) {}
 
-RemarkBase::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned long long n)
+Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned long long n)
     : key(std::string(key)), val(llvm::utostr(n)) {}
 
-void RemarkBase::insert(StringRef s) { args.emplace_back(s); }
+void Remark::insert(StringRef s) { args.emplace_back(s); }
 
-void RemarkBase::insert(RemarkKeyValue a) { args.push_back(std::move(a)); }
+void Remark::insert(RemarkKeyValue a) { args.push_back(std::move(a)); }
 
 // Simple helper to print key=val list.
 static void printArgs(llvm::raw_ostream &os,
-                      llvm::ArrayRef<RemarkBase::RemarkKeyValue> args) {
+                      llvm::ArrayRef<Remark::RemarkKeyValue> args) {
   if (args.empty())
     return;
   os << " {\n";
@@ -79,7 +78,7 @@ static void printArgs(llvm::raw_ostream &os,
   os << "\n}";
 }
 
-void RemarkBase::print(llvm::raw_ostream &os, bool printLocation) const {
+void Remark::print(llvm::raw_ostream &os, bool printLocation) const {
   os << getRemarkTypeString() << "\n";
   os << getPassName() << ":" << getRemarkName() << "\n";
 
@@ -96,7 +95,7 @@ void RemarkBase::print(llvm::raw_ostream &os, bool printLocation) const {
   printArgs(os, getArgs());
 }
 
-std::string RemarkBase::getMsg() const {
+std::string Remark::getMsg() const {
   std::string s;
   llvm::raw_string_ostream os(s);
   print(os);
@@ -104,7 +103,7 @@ std::string RemarkBase::getMsg() const {
   return s;
 }
 
-std::string RemarkBase::getRemarkTypeString() const {
+std::string Remark::getRemarkTypeString() const {
   switch (remarkKind) {
   case RemarkKind::OptimizationRemarkUnknown:
     return "Unknown";
@@ -120,7 +119,7 @@ std::string RemarkBase::getRemarkTypeString() const {
   llvm_unreachable("Unknown remark kind");
 }
 
-llvm::remarks::Type RemarkBase::getRemarkType() const {
+llvm::remarks::Type Remark::getRemarkType() const {
   switch (remarkKind) {
   case RemarkKind::OptimizationRemarkUnknown:
     return llvm::remarks::Type::Unknown;
@@ -136,7 +135,7 @@ llvm::remarks::Type RemarkBase::getRemarkType() const {
   llvm_unreachable("Unknown remark kind");
 }
 
-llvm::remarks::Remark RemarkBase::generateRemark() const {
+llvm::remarks::Remark Remark::generateRemark() const {
   auto locLambda = [&]() -> llvm::remarks::RemarkLocation {
     if (auto flc = dyn_cast<FileLineColLoc>(getLocation()))
       return {flc.getFilename(), flc.getLine(), flc.getColumn()};
@@ -149,7 +148,7 @@ llvm::remarks::Remark RemarkBase::generateRemark() const {
   r.RemarkName = getRemarkName();
   r.FunctionName = getFunction();
   r.Loc = locLambda();
-  for (const RemarkBase::RemarkKeyValue &arg : getArgs()) {
+  for (const Remark::RemarkKeyValue &arg : getArgs()) {
     r.Args.emplace_back();
     r.Args.back().Key = arg.key;
     r.Args.back().Val = arg.val;
@@ -173,8 +172,8 @@ InFlightRemark::~InFlightRemark() {
 
 template <typename RemarkT, typename... Args>
 InFlightRemark RemarkEngine::makeRemark(Args &&...args) {
-  static_assert(std::is_base_of_v<RemarkBase, RemarkT>,
-                "RemarkT must derive from RemarkBase");
+  static_assert(std::is_base_of_v<Remark, RemarkT>,
+                "RemarkT must derive from Remark");
   return InFlightRemark(*this,
                         std::make_unique<RemarkT>(std::forward<Args>(args)...));
 }
@@ -237,7 +236,7 @@ RemarkEngine::emitOptimizationRemarkAnalysis(Location loc, StringRef passName,
 // Remarkengine
 //===----------------------------------------------------------------------===//
 
-void RemarkEngine::report(const RemarkBase &&remark) {
+void RemarkEngine::report(const Remark &&remark) {
   // Stream the remark
   if (remarkStreamer)
     remarkStreamer->streamOptimizationRemark(remark);
@@ -252,7 +251,7 @@ RemarkEngine::~RemarkEngine() {
     remarkStreamer->finalize();
 }
 
-LogicalResult
+llvm::LogicalResult
 RemarkEngine::initialize(std::unique_ptr<MLIRRemarkStreamerBase> streamer,
                          std::string *errMsg) {
   // If you need to validate categories/filters, do so here and set errMsg.
diff --git a/mlir/lib/Remark/RemarkStreamer.cpp b/mlir/lib/Remark/RemarkStreamer.cpp
index be38b434dddc1..c58d8c71531fa 100644
--- a/mlir/lib/Remark/RemarkStreamer.cpp
+++ b/mlir/lib/Remark/RemarkStreamer.cpp
@@ -33,10 +33,10 @@ LLVMRemarkStreamer::createToFile(llvm::StringRef path,
   auto impl = std::unique_ptr<LLVMRemarkStreamer>(new LLVMRemarkStreamer());
   impl->remarkStreamer = std::move(rs);
   impl->file = std::move(f);
-  return std::unique_ptr<MLIRRemarkStreamerBase>(std::move(impl));
+  return std::unique_ptr<mlir::remark::MLIRRemarkStreamerBase>(std::move(impl));
 }
 
-void LLVMRemarkStreamer::streamOptimizationRemark(const RemarkBase &remark) {
+void LLVMRemarkStreamer::streamOptimizationRemark(const Remark &remark) {
   if (!remarkStreamer->matchesFilter(remark.getPassName()))
     return;
 
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index 9b2087ca4d4cf..898a92a9bf29d 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -165,7 +165,7 @@ class MyCustomStreamer : public MLIRRemarkStreamerBase {
 public:
   MyCustomStreamer() = default;
 
-  void streamOptimizationRemark(const RemarkBase &remark) override {
+  void streamOptimizationRemark(const Remark &remark) override {
     llvm::errs() << "Custom remark: ";
     remark.print(llvm::errs(), true);
     llvm::errs() << "\n";

>From 514d429f54ae4476d79742da56143a503cd81614 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Tue, 12 Aug 2025 09:13:03 +0000
Subject: [PATCH 09/22] Pass->Passed

---
 mlir/docs/Remarks.md                      | 12 +++++-----
 mlir/include/mlir/IR/Remarks.h            | 29 +++++++++++++----------
 mlir/include/mlir/Remark/RemarkStreamer.h |  2 +-
 mlir/lib/IR/Remarks.cpp                   | 21 ++++++++--------
 mlir/lib/Remark/RemarkStreamer.cpp        |  2 +-
 mlir/unittests/IR/RemarkTest.cpp          | 13 +++++-----
 6 files changed, 42 insertions(+), 37 deletions(-)

diff --git a/mlir/docs/Remarks.md b/mlir/docs/Remarks.md
index fe243ad30bcc5..adbcc44de9d12 100644
--- a/mlir/docs/Remarks.md
+++ b/mlir/docs/Remarks.md
@@ -2,8 +2,8 @@
 
 [TOC]
 
-Remarks are structured, human- and machine-readable notes emitted by passes to
-explain what was optimized, what was missed, and why. The `RemarkEngine`
+Remarks are structured, human- and machine-readable notes emitted by compiler to
+explain what was transformed, what was missed, and why. The `RemarkEngine`
 collects finalized remarks during compilation and forwards them to a pluggable
 streamer. A default streamer integrates LLVM’s `llvm::remarks` so you can stream
 while a pass runs and serialize to disk (YAML or LLVM bitstream) for tooling.
@@ -13,7 +13,7 @@ while a pass runs and serialize to disk (YAML or LLVM bitstream) for tooling.
 - **Opt-in**: Disabled by default; zero overhead unless enabled.
 - **Per-context**: Configured on `MLIRContext`.
 - **Formats**: Custom streamers, or LLVM’s Remark engine (YAML / Bitstream).
-- **Kinds**: `Pass`, `Missed`, `Failure`, `Analysis`.
+- **Kinds**: `Passed`, `Missed`, `Failure`, `Analysis`.
 - **API**: Lightweight streaming interface with `<<` (similar to diagnostics).
 
 ## How it works
@@ -84,13 +84,13 @@ LogicalResult MyPass::runOnOperation() {
   Location loc = op->getLoc();
 
   // PASS: something succeeded
-  reportOptimizationPass(loc, /*category=*/"vectorizer", /*passName=*/"MyPass")
+  reportRemarkPassed(loc, /*category=*/"vectorizer", /*passName=*/"MyPass")
       << "vectorized loop."
       << Remark::RemarkKeyValue("tripCount", 128);
 
   // ANALYSIS: neutral insight
-  reportOptimizationAnalysis(loc, "unroll", "MyPass")
-      << "estimated cost: " << Remark::RemarkKeyValue("cost", 42);
+  reportOptimizationAnalysis(loc, "RegisterCount", "")
+      << "Kernel uses 168 registers"
 
   // MISSED: explain why + suggest a fix
   reportOptimizationMiss(loc, "unroll", "MyPass",
diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index 7f8e10918dc04..563a57f8d725c 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -25,10 +25,10 @@ namespace mlir::remark {
 /// Defines different remark kinds that can be used to categorize remarks.
 enum class RemarkKind {
   OptimizationRemarkUnknown = 0,
-  OptimizationRemarkPassed,
-  OptimizationRemarkMissed,
-  OptimizationRemarkFailure,
-  OptimizationRemarkAnalysis,
+  OptimizationRemarkPassed,   // Optimization remark that was passed.
+  OptimizationRemarkMissed,   // Optimization remark that was missed.
+  OptimizationRemarkFailure,  // Optimization failure remark.
+  OptimizationRemarkAnalysis, // Analysis remark that does not indicate a pass.
 };
 
 //===----------------------------------------------------------------------===//
@@ -334,15 +334,18 @@ class RemarkEngine {
                                                 StringRef category);
 };
 
+using RemarkKV = remark::Remark::RemarkKeyValue;
+
+} // namespace mlir::remark
+
 //===----------------------------------------------------------------------===//
 // Emitters
 //===----------------------------------------------------------------------===//
-
-using Suggestion = Remark::RemarkKeyValue;
-inline Suggestion suggest(StringRef txt) { return {"Suggestion", txt}; }
+namespace mlir {
+using namespace mlir::remark;
 
 template <typename Fn, typename... Args>
-inline InFlightRemark withEngine(Fn fn, Location loc, Args &&...args) {
+inline remark::InFlightRemark withEngine(Fn fn, Location loc, Args &&...args) {
   MLIRContext *ctx = loc->getContext();
 
   RemarkEngine *enginePtr = ctx->getRemarkEngine();
@@ -354,11 +357,13 @@ inline InFlightRemark withEngine(Fn fn, Location loc, Args &&...args) {
 }
 
 /// Report an optimization remark that was passed.
-inline InFlightRemark reportOptimizationPass(Location loc, StringRef cat,
-                                             StringRef passName) {
+inline InFlightRemark reportRemarkPassed(Location loc, StringRef cat,
+                                         StringRef passName) {
   return withEngine(&RemarkEngine::emitOptimizationRemark, loc, passName, cat);
 }
 
+inline RemarkKV suggest(StringRef s) { return {"Suggestion", s}; }
+
 /// Report an optimization remark that was missed.
 inline InFlightRemark
 reportOptimizationMiss(Location loc, StringRef cat, StringRef passName,
@@ -383,6 +388,6 @@ inline InFlightRemark reportOptimizationAnalysis(Location loc, StringRef cat,
                     passName, cat);
 }
 
-} // namespace mlir::remark
+} // namespace mlir
 
-#endif // MLIR_IR_REMARKS_H
\ No newline at end of file
+#endif // MLIR_IR_REMARKS_H
diff --git a/mlir/include/mlir/Remark/RemarkStreamer.h b/mlir/include/mlir/Remark/RemarkStreamer.h
index d985795ea4280..3c055442bffd6 100644
--- a/mlir/include/mlir/Remark/RemarkStreamer.h
+++ b/mlir/include/mlir/Remark/RemarkStreamer.h
@@ -32,4 +32,4 @@ LogicalResult enableOptimizationRemarksToFile(
     MLIRContext &ctx, StringRef path, llvm::remarks::Format fmt,
     const MLIRContext::RemarkCategories &cat, bool printAsEmitRemarks = false);
 
-} // namespace mlir::remark
\ No newline at end of file
+} // namespace mlir::remark
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
index 6360960b851a1..3dac417037308 100644
--- a/mlir/lib/IR/Remarks.cpp
+++ b/mlir/lib/IR/Remarks.cpp
@@ -1,4 +1,4 @@
-//===- Remarks.cpp - MLIR Remarks ---------------------------------===//
+//===- Remarks.cpp - MLIR Remarks -----------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -67,24 +67,25 @@ static void printArgs(llvm::raw_ostream &os,
                       llvm::ArrayRef<Remark::RemarkKeyValue> args) {
   if (args.empty())
     return;
-  os << " {\n";
+  os << " {";
   for (size_t i = 0; i < args.size(); ++i) {
     const auto &a = args[i];
     os << a.key << "=" << a.val;
     if (i + 1 < args.size())
       os << ", ";
-    os << "\n";
   }
-  os << "\n}";
+  os << "}";
 }
 
+/// Print the remark to the given output stream.
+/// Example output:
+/// [Missed] LoopUnroll:UnrolledLoop func=myFunction @file.cpp:42:7
+/// {tripCount=128, reason=too_small}
 void Remark::print(llvm::raw_ostream &os, bool printLocation) const {
-  os << getRemarkTypeString() << "\n";
-  os << getPassName() << ":" << getRemarkName() << "\n";
-
-  // Function (if any)
-  if (!getFunction().empty())
-    os << " func=" << getFunction() << "\n";
+  os << '[' << getRemarkTypeString() << "] ";
+  os << getPassName() << ':' << getRemarkName();
+  if (functionName)
+    os << " func=" << getFunction() << " ";
 
   if (printLocation)
     if (auto flc = mlir::dyn_cast<mlir::FileLineColLoc>(getLocation()))
diff --git a/mlir/lib/Remark/RemarkStreamer.cpp b/mlir/lib/Remark/RemarkStreamer.cpp
index c58d8c71531fa..b6b4f8bc660c3 100644
--- a/mlir/lib/Remark/RemarkStreamer.cpp
+++ b/mlir/lib/Remark/RemarkStreamer.cpp
@@ -63,4 +63,4 @@ LogicalResult enableOptimizationRemarksToFile(
                                        printAsEmitRemarks);
 }
 
-} // namespace mlir::remark
\ No newline at end of file
+} // namespace mlir::remark
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index 898a92a9bf29d..ba4981260b137 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -61,11 +61,11 @@ TEST(Remark, TestOutputOptimizationRemark) {
     ASSERT_TRUE(succeeded(isEnabled)) << "Failed to enable remark engine";
 
     // Remark 1: pass, category LoopUnroll
-    reportOptimizationPass(loc, categoryLoopunroll, myPassname1) << pass1Msg;
+    reportRemarkPassed(loc, categoryLoopunroll, myPassname1) << pass1Msg;
     // Remark 2: failure, category LoopUnroll
     reportOptimizationFail(loc, categoryLoopunroll, myPassname2) << pass2Msg;
     // Remark 3: pass, category Inline (should not be printed)
-    reportOptimizationPass(loc, categoryInline, myPassname1) << pass3Msg;
+    reportRemarkPassed(loc, categoryInline, myPassname1) << pass3Msg;
   }
 
   // Read the file
@@ -129,8 +129,7 @@ TEST(Remark, TestOutputOptimizationRemarkDiagnostic) {
   std::string funcName("myFunc");
 
   std::string seenMsg = "";
-  std::string expectedMsg = "Passed\nLoopUnroll:myPass1\n func=<unknown "
-                            "function>\n {\nString=My message\n\n}";
+  std::string expectedMsg = "[Passed] LoopUnroll:myPass1 {String=My message}";
   {
     MLIRContext context;
     Location loc = UnknownLoc::get(&context);
@@ -155,7 +154,7 @@ TEST(Remark, TestOutputOptimizationRemarkDiagnostic) {
     ASSERT_TRUE(succeeded(isEnabled)) << "Failed to enable remark engine";
 
     // Remark 1: pass, category LoopUnroll
-    reportOptimizationPass(loc, categoryLoopunroll, myPassname1) << pass1Msg;
+    reportRemarkPassed(loc, categoryLoopunroll, myPassname1) << pass1Msg;
   }
   EXPECT_EQ(seenMsg, expectedMsg);
 }
@@ -201,11 +200,11 @@ TEST(Remark, TestCustomOptimizationRemarkDiagnostic) {
     ASSERT_TRUE(succeeded(isEnabled)) << "Failed to enable remark engine";
 
     // Remark 1: pass, category LoopUnroll
-    reportOptimizationPass(loc, categoryLoopunroll, myPassname1) << pass1Msg;
+    reportRemarkPassed(loc, categoryLoopunroll, myPassname1) << pass1Msg;
     // Remark 2: failure, category LoopUnroll
     reportOptimizationFail(loc, categoryLoopunroll, myPassname2) << pass2Msg;
     // Remark 3: pass, category Inline (should not be printed)
-    reportOptimizationPass(loc, categoryInline, myPassname1) << pass3Msg;
+    reportRemarkPassed(loc, categoryInline, myPassname1) << pass3Msg;
   }
 
   llvm::errs().flush();

>From 6e9b73482db98e76c0ab1829d0a054678274d23b Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Tue, 12 Aug 2025 15:17:36 +0000
Subject: [PATCH 10/22] Add detail. Add Arg.

---
 mlir/docs/Remarks.md                      |  76 ++++++++---
 mlir/include/mlir/IR/MLIRContext.h        |  10 +-
 mlir/include/mlir/IR/Remarks.h            | 153 ++++++++++++++--------
 mlir/include/mlir/Remark/RemarkStreamer.h |  18 ++-
 mlir/lib/IR/MLIRContext.cpp               |  10 +-
 mlir/lib/IR/Remarks.cpp                   |  49 ++-----
 mlir/lib/Remark/RemarkStreamer.cpp        |  10 +-
 mlir/unittests/IR/RemarkTest.cpp          | 126 ++++++++++--------
 8 files changed, 267 insertions(+), 185 deletions(-)

diff --git a/mlir/docs/Remarks.md b/mlir/docs/Remarks.md
index adbcc44de9d12..8bf28a1f19b22 100644
--- a/mlir/docs/Remarks.md
+++ b/mlir/docs/Remarks.md
@@ -12,7 +12,7 @@ while a pass runs and serialize to disk (YAML or LLVM bitstream) for tooling.
 
 - **Opt-in**: Disabled by default; zero overhead unless enabled.
 - **Per-context**: Configured on `MLIRContext`.
-- **Formats**: Custom streamers, or LLVM’s Remark engine (YAML / Bitstream).
+- **Formats**: LLVM’s Remark engine (YAML / Bitstream), or pluggable custom streamers.
 - **Kinds**: `Passed`, `Missed`, `Failure`, `Analysis`.
 - **API**: Lightweight streaming interface with `<<` (similar to diagnostics).
 
@@ -27,11 +27,50 @@ Remarks has two important classes:
   `streamOptimizationRemark(const Remark &)`.
 
 **Default backend – `MLIRLLVMRemarkStreamer`** Adapts `mlir::Remark` to
-`llvm::remarks::Remark` and writes YAML/bitstream via
-`llvm::remarks::RemarkStreamer` to a `ToolOutputFile`.
+`llvm::remarks::detail::Remark` and writes YAML/bitstream via
+`llvm::remarks::detail::RemarkStreamer` to a `ToolOutputFile`.
 
 **Ownership**: `MLIRContext` → `RemarkEngine` → `MLIRRemarkStreamerBase`.
 
+## Categories
+
+There are four built-in categories; you can extend these if needed.
+
+### Passed
+
+A diagnostic indicating the optimization/transformation succeeded.
+
+```c++
+[Passed] Vectorizer:myPass1 {Remark=vectorized loop, tripCount=128}
+```
+
+### Missed
+
+A diagnostic indicating the optimization/transformation did not apply, ideally
+with actionable feedback.
+
+```c++
+[Missed] Unroll: {Reason=tripCount=4 < threshold=256, Suggestion=increase unroll to 128}
+```
+
+### Failure
+
+A diagnostic indicating the optimization/transformation attempted but failed (or
+could not run).
+
+```c++
+[Failure] Unroll: {Reason=failed due to unsupported pattern}
+```
+
+### Analysis
+
+A diagnostic reporting analysis results.
+
+```c++
+[Analysis] Register: {Remark=Kernel uses 168 registers}
+[Analysis] Register: {Remark=Kernel uses 10kB local memory}
+```
+
 ## Enable Remarks via mlir::emitRemarks (No Streamer)
 
 Enable once per `MLIRContext` (e.g., where you build your pass pipeline or in
@@ -55,7 +94,8 @@ context.enableOptimizationRemarks(/*streamer=*/nullptr,
 If you want to persist remarks to a file in YAML or bitstream format, use
 `mlir::remark::LLVMRemarkStreamer` (helper shown below):
 
-You can read more information about [LLVM's Remark from here](https://llvm.org/docs/Remarks.html).
+You can read more information about
+[LLVM's Remark from here](https://llvm.org/docs/Remarks.html).
 
 ```c++
 #include "mlir/Remark/RemarkStreamer.h"
@@ -84,25 +124,27 @@ LogicalResult MyPass::runOnOperation() {
   Location loc = op->getLoc();
 
   // PASS: something succeeded
-  reportRemarkPassed(loc, /*category=*/"vectorizer", /*passName=*/"MyPass")
-      << "vectorized loop."
-      << Remark::RemarkKeyValue("tripCount", 128);
+   remark::passed(loc, categoryVectorizer, myPassname1)
+        << "vectorized loop" << remark::metric("tripCount", 128);
 
   // ANALYSIS: neutral insight
-  reportOptimizationAnalysis(loc, "RegisterCount", "")
-      << "Kernel uses 168 registers"
+  remark::analysis(loc, categoryRegister, "") << "Kernel uses 168 registers";
 
   // MISSED: explain why + suggest a fix
-  reportOptimizationMiss(loc, "unroll", "MyPass",
-                         /*suggestion=*/[&](){ return "increase unroll factor to >=4"; })
-      << "not profitable at this size";
+  int target = 128;
+  int tripBad = 4;
+  int threshold = 256;
+  remark::missed(loc, categoryUnroll)
+      << remark::reason("tripCount={0} < threshold={1}", tripBad, threshold);
+
+  remark::missed(loc, categoryUnroll)
+      << remark::reason("tripCount={0} < threshold={1}", tripBad, threshold)
+      << remark::suggest("increase unroll to {0}", target);
 
   // FAILURE: action attempted but failed
-  if (failed(doThing(op))) {
-    reportOptimizationFail(loc, "pipeline", "MyPass")
-        << "failed due to unsupported pattern";
-    return failure();
-  }
+  remark::failed(loc, categoryUnroll)
+      << remark::reason("failed due to unsupported pattern");
+
   return success();
 }
 ```
diff --git a/mlir/include/mlir/IR/MLIRContext.h b/mlir/include/mlir/IR/MLIRContext.h
index 87786420de37d..2407e4578a41b 100644
--- a/mlir/include/mlir/IR/MLIRContext.h
+++ b/mlir/include/mlir/IR/MLIRContext.h
@@ -34,10 +34,10 @@ class MLIRContextImpl;
 class RegisteredOperationName;
 class StorageUniquer;
 class IRUnit;
-namespace remark {
+namespace remark::detail {
 class MLIRRemarkStreamerBase;
 class RemarkEngine;
-} // namespace remark
+} // namespace remark::detail
 
 /// MLIRContext is the top-level object for a collection of MLIR operations. It
 /// holds immortal uniqued objects like types, and the tables used to unique
@@ -221,7 +221,7 @@ class MLIRContext {
   DiagnosticEngine &getDiagEngine();
 
   /// Returns the remark engine for this context.
-  remark::RemarkEngine *getRemarkEngine();
+  remark::detail::RemarkEngine *getRemarkEngine();
 
   /// Returns the storage uniquer used for creating affine constructs.
   StorageUniquer &getAffineUniquer();
@@ -265,7 +265,7 @@ class MLIRContext {
   /// If `printAsEmitRemarks` is true, the remarks will be printed as
   /// mlir::emitRemarks.
   LogicalResult enableOptimizationRemarks(
-      std::unique_ptr<remark::MLIRRemarkStreamerBase> streamer,
+      std::unique_ptr<remark::detail::MLIRRemarkStreamerBase> streamer,
       const RemarkCategories &cats, bool printAsEmitRemarks = false);
 
   //===--------------------------------------------------------------------===//
@@ -305,7 +305,7 @@ class MLIRContext {
 
 private:
   /// Set the remark engine for this context.
-  void setRemarkEngine(std::unique_ptr<remark::RemarkEngine> engine);
+  void setRemarkEngine(std::unique_ptr<remark::detail::RemarkEngine> engine);
 
   /// Return true if the given dialect is currently loading.
   bool isDialectLoading(StringRef dialectNamespace);
diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index 563a57f8d725c..e30506bb36224 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -13,12 +13,16 @@
 #ifndef MLIR_IR_REMARKS_H
 #define MLIR_IR_REMARKS_H
 
+#include "llvm/ADT/StringExtras.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/Remarks/Remark.h"
+#include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/Regex.h"
+#include <optional>
 
 #include "mlir/IR/Diagnostics.h"
 #include "mlir/IR/MLIRContext.h"
+#include "mlir/IR/Value.h"
 
 namespace mlir::remark {
 
@@ -30,7 +34,9 @@ enum class RemarkKind {
   OptimizationRemarkFailure,  // Optimization failure remark.
   OptimizationRemarkAnalysis, // Analysis remark that does not indicate a pass.
 };
+} // namespace mlir::remark
 
+namespace mlir::remark::detail {
 //===----------------------------------------------------------------------===//
 // Remark Base Class
 //===----------------------------------------------------------------------===//
@@ -43,29 +49,36 @@ class Remark {
       : remarkKind(remarkKind), functionName(functionName), loc(loc),
         passName(passName), remarkName(remarkName) {}
 
-  struct RemarkKeyValue {
+  // Remark argument that is a key-value pair that can be printed as machine
+  // parsable args.
+  struct Arg {
     std::string key;
     std::string val;
-
-    explicit RemarkKeyValue(StringRef str = "") : key("String"), val(str) {}
-    RemarkKeyValue(StringRef key, Value value);
-    RemarkKeyValue(StringRef key, Type type);
-    RemarkKeyValue(StringRef key, StringRef s);
-    RemarkKeyValue(StringRef key, const char *s)
-        : RemarkKeyValue(key, StringRef(s)) {};
-    RemarkKeyValue(StringRef key, int n);
-    RemarkKeyValue(StringRef key, float n);
-    RemarkKeyValue(StringRef key, long n);
-    RemarkKeyValue(StringRef key, long long n);
-    RemarkKeyValue(StringRef key, unsigned n);
-    RemarkKeyValue(StringRef key, unsigned long n);
-    RemarkKeyValue(StringRef key, unsigned long long n);
-    RemarkKeyValue(StringRef key, bool b)
-        : key(key), val(b ? "true" : "false") {}
+    Arg(llvm::StringRef m) : key("Remark"), val(m) {}
+    Arg(llvm::StringRef k, llvm::StringRef v) : key(k), val(v) {}
+    Arg(llvm::StringRef k, std::string v) : key(k), val(std::move(v)) {}
+    Arg(llvm::StringRef k, const char *v) : Arg(k, llvm::StringRef(v)) {}
+    Arg(llvm::StringRef k, Value v);
+    Arg(llvm::StringRef k, Type t);
+    Arg(llvm::StringRef k, bool b) : key(k), val(b ? "true" : "false") {}
+
+    // One constructor for all arithmetic types except bool.
+    template <typename T, typename = std::enable_if_t<std::is_arithmetic_v<T> &&
+                                                      !std::is_same_v<T, bool>>>
+    Arg(llvm::StringRef k, T v) : key(k) {
+      if constexpr (std::is_floating_point_v<T>) {
+        llvm::raw_string_ostream os(val);
+        os << v;
+      } else if constexpr (std::is_signed_v<T>) {
+        val = llvm::itostr(static_cast<long long>(v));
+      } else {
+        val = llvm::utostr(static_cast<unsigned long long>(v));
+      }
+    }
   };
 
-  void insert(StringRef s);
-  void insert(RemarkKeyValue a);
+  void insert(llvm::StringRef s);
+  void insert(Arg a);
 
   void print(llvm::raw_ostream &os, bool printLocation = false) const;
 
@@ -82,7 +95,7 @@ class Remark {
   StringRef getRemarkName() const { return remarkName; }
   std::string getMsg() const;
 
-  ArrayRef<RemarkKeyValue> getArgs() const { return args; }
+  ArrayRef<Arg> getArgs() const { return args; }
 
   llvm::remarks::Type getRemarkType() const;
 
@@ -104,8 +117,8 @@ class Remark {
   /// identify the remark.
   StringRef remarkName;
 
-  /// RemarkKeyValues collected via the streaming interface.
-  SmallVector<RemarkKeyValue, 4> args;
+  /// Args collected via the streaming interface.
+  SmallVector<Arg, 4> args;
 
 private:
   /// Convert the MLIR diagnostic severity to LLVM diagnostic severity.
@@ -149,7 +162,7 @@ inline Remark &&operator<<(Remark &&r, StringRef s) {
   r.insert(s);
   return std::move(r);
 }
-inline Remark &operator<<(Remark &r, const Remark::RemarkKeyValue &kv) {
+inline Remark &operator<<(Remark &r, const Remark::Arg &kv) {
   r.insert(kv);
   return r;
 }
@@ -184,6 +197,12 @@ class RemarkEngine;
 // InFlightRemark
 //===----------------------------------------------------------------------===//
 
+/// Lazy text building for zero cost  string formatting.
+struct LazyTextBuild {
+  llvm::StringRef key;
+  std::function<std::string()> thunk;
+};
+
 /// InFlightRemark is a RAII class that holds a reference to a Remark
 /// instance and allows to build the remark using the << operator. The remark
 /// is emitted when the InFlightRemark instance is destroyed, which happens
@@ -197,7 +216,15 @@ class InFlightRemark {
 
   InFlightRemark() = default; // empty ctor
 
-  template <typename T>
+  InFlightRemark &operator<<(const LazyTextBuild &l) {
+    if (remark)
+      *remark << Remark::Arg(l.key, l.thunk());
+    return *this;
+  }
+
+  // Generic path, but *not* for Lazy
+  template <typename T, typename = std::enable_if_t<
+                            !std::is_same_v<std::decay_t<T>, LazyTextBuild>>>
   InFlightRemark &operator<<(T &&arg) {
     if (remark)
       *remark << std::forward<T>(arg);
@@ -334,18 +361,8 @@ class RemarkEngine {
                                                 StringRef category);
 };
 
-using RemarkKV = remark::Remark::RemarkKeyValue;
-
-} // namespace mlir::remark
-
-//===----------------------------------------------------------------------===//
-// Emitters
-//===----------------------------------------------------------------------===//
-namespace mlir {
-using namespace mlir::remark;
-
 template <typename Fn, typename... Args>
-inline remark::InFlightRemark withEngine(Fn fn, Location loc, Args &&...args) {
+inline InFlightRemark withEngine(Fn fn, Location loc, Args &&...args) {
   MLIRContext *ctx = loc->getContext();
 
   RemarkEngine *enginePtr = ctx->getRemarkEngine();
@@ -356,38 +373,60 @@ inline remark::InFlightRemark withEngine(Fn fn, Location loc, Args &&...args) {
   return {};
 }
 
-/// Report an optimization remark that was passed.
-inline InFlightRemark reportRemarkPassed(Location loc, StringRef cat,
-                                         StringRef passName) {
-  return withEngine(&RemarkEngine::emitOptimizationRemark, loc, passName, cat);
+} // namespace mlir::remark::detail
+
+namespace mlir::remark {
+
+template <class... Ts>
+inline detail::LazyTextBuild reason(const char *fmt, Ts &&...ts) {
+  return {"Reason", [=] { return llvm::formatv(fmt, ts...).str(); }};
 }
 
-inline RemarkKV suggest(StringRef s) { return {"Suggestion", s}; }
+template <class... Ts>
+inline detail::LazyTextBuild suggest(const char *fmt, Ts &&...ts) {
+  return {"Suggestion", [=] { return llvm::formatv(fmt, ts...).str(); }};
+}
+
+template <class V>
+inline detail::LazyTextBuild metric(StringRef key, V &&v) {
+  using DV = std::decay_t<V>;
+  return {key, [key, vv = DV(std::forward<V>(v))]() mutable {
+            // Reuse Arg's formatting logic and return just the value string.
+            return detail::Remark::Arg(key, std::move(vv)).val;
+          }};
+}
+//===----------------------------------------------------------------------===//
+// Emitters
+//===----------------------------------------------------------------------===//
+
+/// Report an optimization remark that was passed.
+inline detail::InFlightRemark passed(Location loc, StringRef cat,
+                                     StringRef passName = {}) {
+  return withEngine(&detail::RemarkEngine::emitOptimizationRemark, loc,
+                    passName, cat);
+}
 
 /// Report an optimization remark that was missed.
-inline InFlightRemark
-reportOptimizationMiss(Location loc, StringRef cat, StringRef passName,
-                       llvm::function_ref<std::string()> makeSuggestion) {
-  auto r =
-      withEngine(&RemarkEngine::emitOptimizationRemarkMiss, loc, passName, cat);
-  if (r)
-    r << suggest(makeSuggestion());
-  return r;
+inline detail::InFlightRemark missed(Location loc, llvm::StringRef cat,
+                                     llvm::StringRef passName = {}) {
+  return withEngine(&detail::RemarkEngine::emitOptimizationRemarkMiss, loc,
+                    passName, cat);
 }
-/// Report an optimization failure remark.
-inline InFlightRemark reportOptimizationFail(Location loc, StringRef cat,
-                                             StringRef passName) {
-  return withEngine(&RemarkEngine::emitOptimizationRemarkFailure, loc, passName,
-                    cat);
+
+/// Report an optimization remark that failed.
+inline detail::InFlightRemark failed(Location loc, llvm::StringRef cat,
+                                     llvm::StringRef passName = {}) {
+  return withEngine(&detail::RemarkEngine::emitOptimizationRemarkFailure, loc,
+                    passName, cat);
 }
 
 /// Report an optimization analysis remark.
-inline InFlightRemark reportOptimizationAnalysis(Location loc, StringRef cat,
-                                                 StringRef passName) {
-  return withEngine(&RemarkEngine::emitOptimizationRemarkAnalysis, loc,
+inline detail::InFlightRemark analysis(Location loc, StringRef cat,
+                                       StringRef passName = {}) {
+  return withEngine(&detail::RemarkEngine::emitOptimizationRemarkAnalysis, loc,
                     passName, cat);
 }
 
-} // namespace mlir
+} // namespace mlir::remark
 
 #endif // MLIR_IR_REMARKS_H
diff --git a/mlir/include/mlir/Remark/RemarkStreamer.h b/mlir/include/mlir/Remark/RemarkStreamer.h
index 3c055442bffd6..532098170ab97 100644
--- a/mlir/include/mlir/Remark/RemarkStreamer.h
+++ b/mlir/include/mlir/Remark/RemarkStreamer.h
@@ -1,10 +1,24 @@
+//===- RemarkStreamer.h - MLIR Optimization Remark ----------------------*-
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines LLVMRemarkStreamer plugging class that uses LLVM's
+// streamer.
+//
+//===----------------------------------------------------------------------===//
+
 #include "mlir/IR/Remarks.h"
 
 #include "llvm/Remarks/RemarkStreamer.h"
 #include "llvm/Support/ToolOutputFile.h"
 
 using namespace llvm;
-namespace mlir::remark {
+namespace mlir::remark::detail {
 
 /// Concrete streamer that writes LLVM optimization remarks to a file
 /// (YAML or Bitstream). Lives outside core.
@@ -23,7 +37,9 @@ class LLVMRemarkStreamer final : public MLIRRemarkStreamerBase {
   std::unique_ptr<class llvm::remarks::RemarkStreamer> remarkStreamer;
   std::unique_ptr<class llvm::ToolOutputFile> file;
 };
+} // namespace mlir::remark::detail
 
+namespace mlir::remark {
 /// Enable optimization remarks to a file with the given path and format.
 /// The remark categories are used to filter the remarks that are emitted.
 /// If the printAsEmitRemarks flag is set, remarks will also be printed using
diff --git a/mlir/lib/IR/MLIRContext.cpp b/mlir/lib/IR/MLIRContext.cpp
index 55cbac4b2f570..5d05e4edc0296 100644
--- a/mlir/lib/IR/MLIRContext.cpp
+++ b/mlir/lib/IR/MLIRContext.cpp
@@ -138,7 +138,7 @@ class MLIRContextImpl {
   //===--------------------------------------------------------------------===//
   // Remark
   //===--------------------------------------------------------------------===//
-  std::unique_ptr<remark::RemarkEngine> remarkEngine;
+  std::unique_ptr<remark::detail::RemarkEngine> remarkEngine;
 
   //===--------------------------------------------------------------------===//
   // Options
@@ -400,19 +400,19 @@ DiagnosticEngine &MLIRContext::getDiagEngine() { return getImpl().diagEngine; }
 
 /// Returns the remark engine for this context.
 void MLIRContext::setRemarkEngine(
-    std::unique_ptr<remark::RemarkEngine> engine) {
+    std::unique_ptr<remark::detail::RemarkEngine> engine) {
   getImpl().remarkEngine = std::move(engine);
 }
 
-remark::RemarkEngine *MLIRContext::getRemarkEngine() {
+remark::detail::RemarkEngine *MLIRContext::getRemarkEngine() {
   return getImpl().remarkEngine.get();
 }
 
 LogicalResult MLIRContext::enableOptimizationRemarks(
-    std::unique_ptr<remark::MLIRRemarkStreamerBase> streamer,
+    std::unique_ptr<remark::detail::MLIRRemarkStreamerBase> streamer,
     const RemarkCategories &cats, bool printAsEmitRemarks) {
   auto engine =
-      std::make_unique<remark::RemarkEngine>(printAsEmitRemarks, cats);
+      std::make_unique<remark::detail::RemarkEngine>(printAsEmitRemarks, cats);
 
   std::string errMsg;
   if (failed(engine->initialize(std::move(streamer), &errMsg))) {
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
index 3dac417037308..3c204a14100de 100644
--- a/mlir/lib/IR/Remarks.cpp
+++ b/mlir/lib/IR/Remarks.cpp
@@ -15,56 +15,27 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 
-using namespace mlir::remark;
+using namespace mlir::remark::detail;
 
 //------------------------------------------------------------------------------
 // Remark
 //------------------------------------------------------------------------------
 
-Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, Value value)
-    : key(std::string(key)) {
-
-  llvm::raw_string_ostream rss(val);
-  rss << value;
+Remark::Arg::Arg(llvm::StringRef k, Value v) : key(k) {
+  llvm::raw_string_ostream os(val);
+  os << v;
 }
 
-Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, Type type)
-    : key(std::string(key)) {
+Remark::Arg::Arg(llvm::StringRef k, Type t) : key(k) {
   llvm::raw_string_ostream os(val);
-  os << type;
+  os << t;
 }
 
-Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, StringRef s)
-    : key(std::string(key)), val(s.str()) {}
-
-Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, int n)
-    : key(std::string(key)), val(llvm::itostr(n)) {}
-
-Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, float n)
-    : key(std::string(key)), val(std::to_string(n)) {}
-
-Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, long n)
-    : key(std::string(key)), val(llvm::itostr(n)) {}
-
-Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, long long n)
-    : key(std::string(key)), val(llvm::itostr(n)) {}
-
-Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned n)
-    : key(std::string(key)), val(llvm::utostr(n)) {}
-
-Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned long n)
-    : key(std::string(key)), val(llvm::utostr(n)) {}
-
-Remark::RemarkKeyValue::RemarkKeyValue(StringRef key, unsigned long long n)
-    : key(std::string(key)), val(llvm::utostr(n)) {}
-
-void Remark::insert(StringRef s) { args.emplace_back(s); }
-
-void Remark::insert(RemarkKeyValue a) { args.push_back(std::move(a)); }
+void Remark::insert(llvm::StringRef s) { args.emplace_back(s); }
+void Remark::insert(Arg a) { args.push_back(std::move(a)); }
 
 // Simple helper to print key=val list.
-static void printArgs(llvm::raw_ostream &os,
-                      llvm::ArrayRef<Remark::RemarkKeyValue> args) {
+static void printArgs(llvm::raw_ostream &os, llvm::ArrayRef<Remark::Arg> args) {
   if (args.empty())
     return;
   os << " {";
@@ -149,7 +120,7 @@ llvm::remarks::Remark Remark::generateRemark() const {
   r.RemarkName = getRemarkName();
   r.FunctionName = getFunction();
   r.Loc = locLambda();
-  for (const Remark::RemarkKeyValue &arg : getArgs()) {
+  for (const Remark::Arg &arg : getArgs()) {
     r.Args.emplace_back();
     r.Args.back().Key = arg.key;
     r.Args.back().Val = arg.val;
diff --git a/mlir/lib/Remark/RemarkStreamer.cpp b/mlir/lib/Remark/RemarkStreamer.cpp
index b6b4f8bc660c3..3ca99746c1f9f 100644
--- a/mlir/lib/Remark/RemarkStreamer.cpp
+++ b/mlir/lib/Remark/RemarkStreamer.cpp
@@ -8,7 +8,7 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/ToolOutputFile.h"
 
-namespace mlir::remark {
+namespace mlir::remark::detail {
 
 FailureOr<std::unique_ptr<MLIRRemarkStreamerBase>>
 LLVMRemarkStreamer::createToFile(llvm::StringRef path,
@@ -33,7 +33,7 @@ LLVMRemarkStreamer::createToFile(llvm::StringRef path,
   auto impl = std::unique_ptr<LLVMRemarkStreamer>(new LLVMRemarkStreamer());
   impl->remarkStreamer = std::move(rs);
   impl->file = std::move(f);
-  return std::unique_ptr<mlir::remark::MLIRRemarkStreamerBase>(std::move(impl));
+  return std::unique_ptr<MLIRRemarkStreamerBase>(std::move(impl));
 }
 
 void LLVMRemarkStreamer::streamOptimizationRemark(const Remark &remark) {
@@ -50,13 +50,15 @@ LLVMRemarkStreamer::~LLVMRemarkStreamer() {
   if (file && remarkStreamer)
     file->keep();
 }
+} // namespace mlir::remark::detail
 
+namespace mlir::remark {
 LogicalResult enableOptimizationRemarksToFile(
     MLIRContext &ctx, StringRef path, llvm::remarks::Format fmt,
     const MLIRContext::RemarkCategories &cat, bool printAsEmitRemarks) {
 
-  FailureOr<std::unique_ptr<MLIRRemarkStreamerBase>> sOr =
-      LLVMRemarkStreamer::createToFile(path, fmt);
+  FailureOr<std::unique_ptr<detail::MLIRRemarkStreamerBase>> sOr =
+      detail::LLVMRemarkStreamer::createToFile(path, fmt);
   if (failed(sOr))
     return failure();
   return ctx.enableOptimizationRemarks(std::move(*sOr), cat,
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index ba4981260b137..9106cfeaba3cd 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -22,20 +22,14 @@
 
 using namespace llvm;
 using namespace mlir;
-using namespace mlir::detail;
 
 namespace {
 
 TEST(Remark, TestOutputOptimizationRemark) {
-  const auto *pass1Msg = "My message";
-  const auto *pass2Msg = "My another message";
-  const auto *pass3Msg = "Do not show this message";
-
-  std::string categoryLoopunroll("LoopUnroll");
-  std::string categoryInline("Inliner");
+  std::string categoryVectorizer("Vectorizer");
+  std::string categoryRegister("Register");
+  std::string categoryUnroll("Unroll");
   std::string myPassname1("myPass1");
-  std::string myPassname2("myPass2");
-  std::string funcName("myFunc");
   SmallString<64> tmpPathStorage;
   sys::fs::createUniquePath("remarks-%%%%%%.yaml", tmpPathStorage,
                             /*MakeAbsolute=*/true);
@@ -51,45 +45,36 @@ TEST(Remark, TestOutputOptimizationRemark) {
     context.printStackTraceOnDiagnostic(true);
 
     // Setup the remark engine
-    mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryLoopunroll,
-                                             /*missed=*/std::nullopt,
-                                             /*analysis=*/std::nullopt,
-                                             /*failed=*/categoryLoopunroll};
+    mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryVectorizer,
+                                             /*missed=*/categoryUnroll,
+                                             /*analysis=*/categoryRegister,
+                                             /*failed=*/categoryUnroll};
 
     LogicalResult isEnabled = mlir::remark::enableOptimizationRemarksToFile(
         context, yamlFile, llvm::remarks::Format::YAML, cats);
     ASSERT_TRUE(succeeded(isEnabled)) << "Failed to enable remark engine";
 
-    // Remark 1: pass, category LoopUnroll
-    reportRemarkPassed(loc, categoryLoopunroll, myPassname1) << pass1Msg;
-    // Remark 2: failure, category LoopUnroll
-    reportOptimizationFail(loc, categoryLoopunroll, myPassname2) << pass2Msg;
-    // Remark 3: pass, category Inline (should not be printed)
-    reportRemarkPassed(loc, categoryInline, myPassname1) << pass3Msg;
+    // PASS: something succeeded
+    remark::passed(loc, categoryVectorizer, myPassname1)
+        << "vectorized loop" << remark::metric("tripCount", 128);
+
+    // ANALYSIS: neutral insight
+    remark::analysis(loc, categoryRegister, "") << "Kernel uses 168 registers";
+
+    // MISSED: explain why + suggest a fix
+    remark::missed(loc, categoryUnroll, "MyPass")
+        << remark::reason("not profitable at this size"),
+        remark::suggest("increase unroll factor to >=4");
+
+    // FAILURE: action attempted but failed
+    remark::failed(loc, categoryUnroll, "MyPass")
+        << remark::reason("failed due to unsupported pattern");
   }
 
   // Read the file
   auto bufferOrErr = MemoryBuffer::getFile(yamlFile);
   ASSERT_TRUE(static_cast<bool>(bufferOrErr)) << "Failed to open remarks file";
   std::string content = bufferOrErr.get()->getBuffer().str();
-
-  // Remark 1: pass, should be printed
-  EXPECT_NE(content.find("--- !Passed"), std::string::npos);
-  EXPECT_NE(content.find("Pass:            " + categoryLoopunroll),
-            std::string::npos);
-  EXPECT_NE(content.find("Name:            " + myPassname1), std::string::npos);
-  EXPECT_NE(content.find("String:          " + std::string(pass1Msg)),
-            std::string::npos);
-
-  // Remark 2: failure, should be printed
-  EXPECT_NE(content.find("--- !Failure"), std::string::npos);
-  EXPECT_NE(content.find("Name:            " + myPassname2), std::string::npos);
-  EXPECT_NE(content.find("String:          " + std::string(pass2Msg)),
-            std::string::npos);
-
-  // Remark 3: pass, category Inline (should not be printed)
-  EXPECT_EQ(content.find("String:          " + std::string(pass3Msg)),
-            std::string::npos);
 }
 
 TEST(Remark, TestNoOutputOptimizationRemark) {
@@ -112,7 +97,8 @@ TEST(Remark, TestNoOutputOptimizationRemark) {
   {
     MLIRContext context;
     Location loc = UnknownLoc::get(&context);
-    reportOptimizationFail(loc, categoryFailName, myPassname1) << pass1Msg;
+    remark::failed(loc, categoryFailName, myPassname1)
+        << remark::reason(pass1Msg);
   }
   // No setup, so no output file should be created
   // check!
@@ -122,14 +108,12 @@ TEST(Remark, TestNoOutputOptimizationRemark) {
 }
 
 TEST(Remark, TestOutputOptimizationRemarkDiagnostic) {
-  const auto *pass1Msg = "My message";
-
-  std::string categoryLoopunroll("LoopUnroll");
+  std::string categoryVectorizer("Vectorizer");
+  std::string categoryRegister("Register");
+  std::string categoryUnroll("Unroll");
   std::string myPassname1("myPass1");
-  std::string funcName("myFunc");
 
-  std::string seenMsg = "";
-  std::string expectedMsg = "[Passed] LoopUnroll:myPass1 {String=My message}";
+  llvm::SmallVector<std::string> seenMsg;
   {
     MLIRContext context;
     Location loc = UnknownLoc::get(&context);
@@ -139,32 +123,59 @@ TEST(Remark, TestOutputOptimizationRemarkDiagnostic) {
 
     // Register a handler that captures the diagnostic.
     ScopedDiagnosticHandler handler(&context, [&](Diagnostic &diag) {
-      seenMsg = diag.str();
+      seenMsg.push_back(diag.str());
       return success();
     });
 
     // Setup the remark engine
-    mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryLoopunroll,
-                                             /*missed=*/std::nullopt,
-                                             /*analysis=*/std::nullopt,
-                                             /*failed=*/categoryLoopunroll};
+    mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryVectorizer,
+                                             /*missed=*/categoryUnroll,
+                                             /*analysis=*/categoryRegister,
+                                             /*failed=*/categoryUnroll};
 
     LogicalResult isEnabled =
         context.enableOptimizationRemarks(nullptr, cats, true);
+
     ASSERT_TRUE(succeeded(isEnabled)) << "Failed to enable remark engine";
 
-    // Remark 1: pass, category LoopUnroll
-    reportRemarkPassed(loc, categoryLoopunroll, myPassname1) << pass1Msg;
+    // PASS: something succeeded
+    remark::passed(loc, categoryVectorizer, myPassname1)
+        << "vectorized loop" << remark::metric("tripCount", 128);
+
+    // ANALYSIS: neutral insight
+    remark::analysis(loc, categoryRegister, "") << "Kernel uses 168 registers";
+
+    // MISSED: explain why + suggest a fix
+    int target = 128;
+    int tripBad = 4;
+    int threshold = 256;
+
+    remark::missed(loc, categoryUnroll)
+        << remark::reason("tripCount={0} < threshold={1}", tripBad, threshold);
+
+    remark::missed(loc, categoryUnroll)
+        << remark::reason("tripCount={0} < threshold={1}", tripBad, threshold)
+        << remark::suggest("increase unroll to {0}", target);
+
+    // FAILURE: action attempted but failed
+    remark::failed(loc, categoryUnroll)
+        << remark::reason("failed due to unsupported pattern");
   }
-  EXPECT_EQ(seenMsg, expectedMsg);
+  // clang-format off
+  EXPECT_EQ(seenMsg[0], "[Passed] Vectorizer:myPass1 {Remark=vectorized loop, tripCount=128}");
+  EXPECT_EQ(seenMsg[1], "[Analysis] Register: {Remark=Kernel uses 168 registers}");
+  EXPECT_EQ(seenMsg[2], "[Missed] Unroll: {Reason=tripCount=4 < threshold=256}");
+  EXPECT_EQ(seenMsg[3], "[Missed] Unroll: {Reason=tripCount=4 < threshold=256, Suggestion=increase unroll to 128}");
+  EXPECT_EQ(seenMsg[4], "[Failure] Unroll: {Reason=failed due to unsupported pattern}");
+  // clang-format on
 }
 
 /// Custom remark streamer that prints remarks to stderr.
-class MyCustomStreamer : public MLIRRemarkStreamerBase {
+class MyCustomStreamer : public remark::detail::MLIRRemarkStreamerBase {
 public:
   MyCustomStreamer() = default;
 
-  void streamOptimizationRemark(const Remark &remark) override {
+  void streamOptimizationRemark(const remark::detail::Remark &remark) override {
     llvm::errs() << "Custom remark: ";
     remark.print(llvm::errs(), true);
     llvm::errs() << "\n";
@@ -200,11 +211,12 @@ TEST(Remark, TestCustomOptimizationRemarkDiagnostic) {
     ASSERT_TRUE(succeeded(isEnabled)) << "Failed to enable remark engine";
 
     // Remark 1: pass, category LoopUnroll
-    reportRemarkPassed(loc, categoryLoopunroll, myPassname1) << pass1Msg;
+    remark::passed(loc, categoryLoopunroll, myPassname1) << pass1Msg;
     // Remark 2: failure, category LoopUnroll
-    reportOptimizationFail(loc, categoryLoopunroll, myPassname2) << pass2Msg;
+    remark::failed(loc, categoryLoopunroll, myPassname2)
+        << remark::reason(pass2Msg);
     // Remark 3: pass, category Inline (should not be printed)
-    reportRemarkPassed(loc, categoryInline, myPassname1) << pass3Msg;
+    remark::passed(loc, categoryInline, myPassname1) << pass3Msg;
   }
 
   llvm::errs().flush();

>From 2bd50fd5a428c26d9daf86bdad54728ed45187a1 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Tue, 12 Aug 2025 15:22:08 +0000
Subject: [PATCH 11/22] move RemarkCategories-> mlir::remark

---
 mlir/include/mlir/IR/MLIRContext.h        |  8 ++++----
 mlir/include/mlir/IR/Remarks.h            |  6 ++++--
 mlir/include/mlir/Remark/RemarkStreamer.h |  7 ++++---
 mlir/lib/IR/MLIRContext.cpp               |  2 +-
 mlir/lib/IR/Remarks.cpp                   |  2 +-
 mlir/lib/Remark/RemarkStreamer.cpp        |  7 ++++---
 mlir/unittests/IR/RemarkTest.cpp          | 24 +++++++++++------------
 7 files changed, 30 insertions(+), 26 deletions(-)

diff --git a/mlir/include/mlir/IR/MLIRContext.h b/mlir/include/mlir/IR/MLIRContext.h
index 2407e4578a41b..25a07962dd863 100644
--- a/mlir/include/mlir/IR/MLIRContext.h
+++ b/mlir/include/mlir/IR/MLIRContext.h
@@ -34,6 +34,9 @@ class MLIRContextImpl;
 class RegisteredOperationName;
 class StorageUniquer;
 class IRUnit;
+namespace remark {
+struct RemarkCategories;
+}
 namespace remark::detail {
 class MLIRRemarkStreamerBase;
 class RemarkEngine;
@@ -64,9 +67,6 @@ class RemarkEngine;
 class MLIRContext {
 public:
   enum class Threading { DISABLED, ENABLED };
-  struct RemarkCategories {
-    std::optional<std::string> passed, missed, analysis, failed;
-  };
 
   /// Create a new Context.
   explicit MLIRContext(Threading multithreading = Threading::ENABLED);
@@ -266,7 +266,7 @@ class MLIRContext {
   /// mlir::emitRemarks.
   LogicalResult enableOptimizationRemarks(
       std::unique_ptr<remark::detail::MLIRRemarkStreamerBase> streamer,
-      const RemarkCategories &cats, bool printAsEmitRemarks = false);
+      const remark::RemarkCategories &cats, bool printAsEmitRemarks = false);
 
   //===--------------------------------------------------------------------===//
   // Action API
diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index e30506bb36224..7ba7a190324e4 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -25,6 +25,9 @@
 #include "mlir/IR/Value.h"
 
 namespace mlir::remark {
+struct RemarkCategories {
+  std::optional<std::string> passed, missed, analysis, failed;
+};
 
 /// Defines different remark kinds that can be used to categorize remarks.
 enum class RemarkKind {
@@ -328,8 +331,7 @@ class RemarkEngine {
   /// Constructs Remark engine with optional category names. If a category
   /// name is not provided, it is not enabled. The category names are used to
   /// filter the remarks that are emitted.
-  RemarkEngine(bool printAsEmitRemarks,
-               const MLIRContext::RemarkCategories &cats);
+  RemarkEngine(bool printAsEmitRemarks, const RemarkCategories &cats);
 
   /// Destructor that will close the output file and reset the
   /// main remark streamer.
diff --git a/mlir/include/mlir/Remark/RemarkStreamer.h b/mlir/include/mlir/Remark/RemarkStreamer.h
index 532098170ab97..dd3b269c27faf 100644
--- a/mlir/include/mlir/Remark/RemarkStreamer.h
+++ b/mlir/include/mlir/Remark/RemarkStreamer.h
@@ -44,8 +44,9 @@ namespace mlir::remark {
 /// The remark categories are used to filter the remarks that are emitted.
 /// If the printAsEmitRemarks flag is set, remarks will also be printed using
 /// mlir::emitRemarks.
-LogicalResult enableOptimizationRemarksToFile(
-    MLIRContext &ctx, StringRef path, llvm::remarks::Format fmt,
-    const MLIRContext::RemarkCategories &cat, bool printAsEmitRemarks = false);
+LogicalResult enableOptimizationRemarksToFile(MLIRContext &ctx, StringRef path,
+                                              llvm::remarks::Format fmt,
+                                              const RemarkCategories &cat,
+                                              bool printAsEmitRemarks = false);
 
 } // namespace mlir::remark
diff --git a/mlir/lib/IR/MLIRContext.cpp b/mlir/lib/IR/MLIRContext.cpp
index 5d05e4edc0296..0f68af77a598b 100644
--- a/mlir/lib/IR/MLIRContext.cpp
+++ b/mlir/lib/IR/MLIRContext.cpp
@@ -410,7 +410,7 @@ remark::detail::RemarkEngine *MLIRContext::getRemarkEngine() {
 
 LogicalResult MLIRContext::enableOptimizationRemarks(
     std::unique_ptr<remark::detail::MLIRRemarkStreamerBase> streamer,
-    const RemarkCategories &cats, bool printAsEmitRemarks) {
+    const remark::RemarkCategories &cats, bool printAsEmitRemarks) {
   auto engine =
       std::make_unique<remark::detail::RemarkEngine>(printAsEmitRemarks, cats);
 
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
index 3c204a14100de..752d3d29b263b 100644
--- a/mlir/lib/IR/Remarks.cpp
+++ b/mlir/lib/IR/Remarks.cpp
@@ -232,7 +232,7 @@ RemarkEngine::initialize(std::unique_ptr<MLIRRemarkStreamerBase> streamer,
 }
 
 RemarkEngine::RemarkEngine(bool printAsEmitRemarks,
-                           const MLIRContext::RemarkCategories &cats)
+                           const RemarkCategories &cats)
     : printAsEmitRemarks(printAsEmitRemarks) {
   if (cats.passed)
     passFilter = llvm::Regex(cats.passed.value());
diff --git a/mlir/lib/Remark/RemarkStreamer.cpp b/mlir/lib/Remark/RemarkStreamer.cpp
index 3ca99746c1f9f..e862543b682fe 100644
--- a/mlir/lib/Remark/RemarkStreamer.cpp
+++ b/mlir/lib/Remark/RemarkStreamer.cpp
@@ -53,9 +53,10 @@ LLVMRemarkStreamer::~LLVMRemarkStreamer() {
 } // namespace mlir::remark::detail
 
 namespace mlir::remark {
-LogicalResult enableOptimizationRemarksToFile(
-    MLIRContext &ctx, StringRef path, llvm::remarks::Format fmt,
-    const MLIRContext::RemarkCategories &cat, bool printAsEmitRemarks) {
+LogicalResult enableOptimizationRemarksToFile(MLIRContext &ctx, StringRef path,
+                                              llvm::remarks::Format fmt,
+                                              const RemarkCategories &cat,
+                                              bool printAsEmitRemarks) {
 
   FailureOr<std::unique_ptr<detail::MLIRRemarkStreamerBase>> sOr =
       detail::LLVMRemarkStreamer::createToFile(path, fmt);
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index 9106cfeaba3cd..1f9158055a13b 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -45,10 +45,10 @@ TEST(Remark, TestOutputOptimizationRemark) {
     context.printStackTraceOnDiagnostic(true);
 
     // Setup the remark engine
-    mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryVectorizer,
-                                             /*missed=*/categoryUnroll,
-                                             /*analysis=*/categoryRegister,
-                                             /*failed=*/categoryUnroll};
+    mlir::remark::RemarkCategories cats{/*passed=*/categoryVectorizer,
+                                        /*missed=*/categoryUnroll,
+                                        /*analysis=*/categoryRegister,
+                                        /*failed=*/categoryUnroll};
 
     LogicalResult isEnabled = mlir::remark::enableOptimizationRemarksToFile(
         context, yamlFile, llvm::remarks::Format::YAML, cats);
@@ -128,10 +128,10 @@ TEST(Remark, TestOutputOptimizationRemarkDiagnostic) {
     });
 
     // Setup the remark engine
-    mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryVectorizer,
-                                             /*missed=*/categoryUnroll,
-                                             /*analysis=*/categoryRegister,
-                                             /*failed=*/categoryUnroll};
+    mlir::remark::RemarkCategories cats{/*passed=*/categoryVectorizer,
+                                        /*missed=*/categoryUnroll,
+                                        /*analysis=*/categoryRegister,
+                                        /*failed=*/categoryUnroll};
 
     LogicalResult isEnabled =
         context.enableOptimizationRemarks(nullptr, cats, true);
@@ -201,10 +201,10 @@ TEST(Remark, TestCustomOptimizationRemarkDiagnostic) {
     Location loc = UnknownLoc::get(&context);
 
     // Setup the remark engine
-    mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryLoopunroll,
-                                             /*missed=*/std::nullopt,
-                                             /*analysis=*/std::nullopt,
-                                             /*failed=*/categoryLoopunroll};
+    mlir::remark::RemarkCategories cats{/*passed=*/categoryLoopunroll,
+                                        /*missed=*/std::nullopt,
+                                        /*analysis=*/std::nullopt,
+                                        /*failed=*/categoryLoopunroll};
 
     LogicalResult isEnabled = context.enableOptimizationRemarks(
         std::make_unique<MyCustomStreamer>(), cats, true);

>From a825d7f5b8cfb934528f416713fb68bebeb73a07 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Tue, 12 Aug 2025 15:23:39 +0000
Subject: [PATCH 12/22] fix copilot

---
 mlir/docs/Remarks.md                      | 4 ++--
 mlir/include/mlir/Remark/RemarkStreamer.h | 1 -
 mlir/lib/IR/Remarks.cpp                   | 2 +-
 mlir/lib/Remark/CMakeLists.txt            | 2 +-
 4 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/mlir/docs/Remarks.md b/mlir/docs/Remarks.md
index 8bf28a1f19b22..22731d25eb507 100644
--- a/mlir/docs/Remarks.md
+++ b/mlir/docs/Remarks.md
@@ -79,7 +79,7 @@ context’s `DiagnosticEngine` under the provided category labels—handy for
 interactive tools and tests.
 
 ```c++
-mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryLoopunroll,
+mlir::remark::RemarkCategories cats{/*passed=*/categoryLoopunroll,
                                           /*missed=*/std::nullopt,
                                           /*analysis=*/std::nullopt,
                                           /*failed=*/categoryLoopunroll};
@@ -100,7 +100,7 @@ You can read more information about
 ```c++
 #include "mlir/Remark/RemarkStreamer.h"
 
-mlir::MLIRContext::RemarkCategories cats{/*passed=*/categoryLoopunroll,
+mlir::remark::RemarkCategories cats{/*passed=*/categoryLoopunroll,
                                          /*missed=*/std::nullopt,
                                          /*analysis=*/std::nullopt,
                                          /*failed=*/categoryLoopunroll};
diff --git a/mlir/include/mlir/Remark/RemarkStreamer.h b/mlir/include/mlir/Remark/RemarkStreamer.h
index dd3b269c27faf..148629223b530 100644
--- a/mlir/include/mlir/Remark/RemarkStreamer.h
+++ b/mlir/include/mlir/Remark/RemarkStreamer.h
@@ -17,7 +17,6 @@
 #include "llvm/Remarks/RemarkStreamer.h"
 #include "llvm/Support/ToolOutputFile.h"
 
-using namespace llvm;
 namespace mlir::remark::detail {
 
 /// Concrete streamer that writes LLVM optimization remarks to a file
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
index 752d3d29b263b..abc042d0e4cb3 100644
--- a/mlir/lib/IR/Remarks.cpp
+++ b/mlir/lib/IR/Remarks.cpp
@@ -205,7 +205,7 @@ RemarkEngine::emitOptimizationRemarkAnalysis(Location loc, StringRef passName,
 }
 
 //===----------------------------------------------------------------------===//
-// Remarkengine
+// RemarkEngine
 //===----------------------------------------------------------------------===//
 
 void RemarkEngine::report(const Remark &&remark) {
diff --git a/mlir/lib/Remark/CMakeLists.txt b/mlir/lib/Remark/CMakeLists.txt
index 4888d71a7ad66..920a95db4f07b 100644
--- a/mlir/lib/Remark/CMakeLists.txt
+++ b/mlir/lib/Remark/CMakeLists.txt
@@ -10,5 +10,5 @@ add_mlir_library(MLIRRemarkStreamer
   LINK_COMPONENTS
     Remarks
     Core
-    BitstreamReader  
+    BitstreamReader
   )

>From 2fbb84a7551617b9eafe5d17ca6a5eac76517650 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Tue, 12 Aug 2025 15:26:45 +0000
Subject: [PATCH 13/22] fx

---
 mlir/unittests/IR/RemarkTest.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index 1f9158055a13b..7b2bef9f62724 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -63,8 +63,8 @@ TEST(Remark, TestOutputOptimizationRemark) {
 
     // MISSED: explain why + suggest a fix
     remark::missed(loc, categoryUnroll, "MyPass")
-        << remark::reason("not profitable at this size"),
-        remark::suggest("increase unroll factor to >=4");
+        << remark::reason("not profitable at this size")
+        << remark::suggest("increase unroll factor to >=4");
 
     // FAILURE: action attempted but failed
     remark::failed(loc, categoryUnroll, "MyPass")

>From 0c4b3866c19663ba5ebb4138af4bf0892f4ed5b6 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Tue, 12 Aug 2025 16:00:52 +0000
Subject: [PATCH 14/22] fix comment

---
 mlir/include/mlir/IR/MLIRContext.h | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/mlir/include/mlir/IR/MLIRContext.h b/mlir/include/mlir/IR/MLIRContext.h
index 25a07962dd863..6c3aac418fa79 100644
--- a/mlir/include/mlir/IR/MLIRContext.h
+++ b/mlir/include/mlir/IR/MLIRContext.h
@@ -67,7 +67,6 @@ class RemarkEngine;
 class MLIRContext {
 public:
   enum class Threading { DISABLED, ENABLED };
-
   /// Create a new Context.
   explicit MLIRContext(Threading multithreading = Threading::ENABLED);
   explicit MLIRContext(const DialectRegistry &registry,
@@ -256,14 +255,14 @@ class MLIRContext {
   /// (attributes, operations, types, etc.).
   llvm::hash_code getRegistryHash();
 
-  /// Setup optimization remarks for the context.
-  /// This will enable the remark engine and set the streamer to be used for
-  /// optimization remarks.
+  /// Setup remarks for the context. This function will enable the remark engine
+  /// and set the streamer to be used for optimization remarks.
   /// The remark categories are used to filter the remarks that will be emitted
   /// by the remark engine. If a category is not specified, it will not be
-  /// emitted.
-  /// If `printAsEmitRemarks` is true, the remarks will be printed as
+  /// emitted. If `printAsEmitRemarks` is true, the remarks will be printed as
   /// mlir::emitRemarks.
+  /// 'streamer' must inherit from MLIRRemarkStreamerBase and will be used to
+  /// stream the remarks.
   LogicalResult enableOptimizationRemarks(
       std::unique_ptr<remark::detail::MLIRRemarkStreamerBase> streamer,
       const remark::RemarkCategories &cats, bool printAsEmitRemarks = false);

>From 0b43c0ce3704f71c566b228624586c66ea23750c Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Tue, 12 Aug 2025 16:01:04 +0000
Subject: [PATCH 15/22] add test

---
 mlir/unittests/IR/RemarkTest.cpp | 42 +++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index 7b2bef9f62724..027d9c694097e 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -17,12 +17,13 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/LogicalResult.h"
 #include "llvm/Support/YAMLParser.h"
+#include "gmock/gmock.h"
 #include "gtest/gtest.h"
 #include <optional>
 
 using namespace llvm;
 using namespace mlir;
-
+using namespace testing;
 namespace {
 
 TEST(Remark, TestOutputOptimizationRemark) {
@@ -75,6 +76,45 @@ TEST(Remark, TestOutputOptimizationRemark) {
   auto bufferOrErr = MemoryBuffer::getFile(yamlFile);
   ASSERT_TRUE(static_cast<bool>(bufferOrErr)) << "Failed to open remarks file";
   std::string content = bufferOrErr.get()->getBuffer().str();
+
+  EXPECT_THAT(content, HasSubstr("--- !Passed"));
+  EXPECT_THAT(content, HasSubstr("Pass:            Vectorizer"));
+  EXPECT_THAT(content, HasSubstr("Name:            myPass1"));
+  EXPECT_THAT(content, HasSubstr("Remark:          vectorized loop"));
+  EXPECT_THAT(content, HasSubstr("tripCount:       '128'"));
+
+  EXPECT_THAT(content, HasSubstr("--- !Analysis"));
+  EXPECT_THAT(content, HasSubstr("Pass:            Register"));
+  EXPECT_THAT(content, HasSubstr("Remark:          Kernel uses 168 registers"));
+
+  EXPECT_THAT(content, HasSubstr("--- !Missed"));
+  EXPECT_THAT(content, HasSubstr("Pass:            Unroll"));
+  EXPECT_THAT(content, HasSubstr("Name:            MyPass"));
+  EXPECT_THAT(content,
+              HasSubstr("Reason:          not profitable at this size"));
+  EXPECT_THAT(content,
+              HasSubstr("Suggestion:      'increase unroll factor to >=4'"));
+
+  EXPECT_THAT(content, HasSubstr("--- !Failure"));
+  EXPECT_THAT(content, HasSubstr("Pass:            Unroll"));
+  EXPECT_THAT(content, HasSubstr("Name:            MyPass"));
+  EXPECT_THAT(content,
+              HasSubstr("Reason:          failed due to unsupported pattern"));
+
+  // Also verify document order to avoid false positives.
+  size_t iPassed = content.find("--- !Passed");
+  size_t iAnalysis = content.find("--- !Analysis");
+  size_t iMissed = content.find("--- !Missed");
+  size_t iFailure = content.find("--- !Failure");
+
+  ASSERT_NE(iPassed, std::string::npos);
+  ASSERT_NE(iAnalysis, std::string::npos);
+  ASSERT_NE(iMissed, std::string::npos);
+  ASSERT_NE(iFailure, std::string::npos);
+
+  EXPECT_LT(iPassed, iAnalysis);
+  EXPECT_LT(iAnalysis, iMissed);
+  EXPECT_LT(iMissed, iFailure);
 }
 
 TEST(Remark, TestNoOutputOptimizationRemark) {

>From a58c20f7db83b54d2b3dd7d204e6c881d56624d0 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Tue, 12 Aug 2025 16:28:20 +0000
Subject: [PATCH 16/22] improve the doc

---
 mlir/docs/Remarks.md | 224 ++++++++++++++++++++++---------------------
 1 file changed, 117 insertions(+), 107 deletions(-)

diff --git a/mlir/docs/Remarks.md b/mlir/docs/Remarks.md
index 22731d25eb507..35fc2eadcd793 100644
--- a/mlir/docs/Remarks.md
+++ b/mlir/docs/Remarks.md
@@ -1,147 +1,118 @@
 # Remark Infrastructure
 
-[TOC]
+Remarks are **structured, human- and machine-readable notes** emitted by the
+compiler to explain:
 
-Remarks are structured, human- and machine-readable notes emitted by compiler to
-explain what was transformed, what was missed, and why. The `RemarkEngine`
-collects finalized remarks during compilation and forwards them to a pluggable
-streamer. A default streamer integrates LLVM’s `llvm::remarks` so you can stream
-while a pass runs and serialize to disk (YAML or LLVM bitstream) for tooling.
+- What was transformed
+- What was missed
+- Why it happened
 
-**Key points**
+The **`RemarkEngine`** collects finalized remarks during compilation and sends
+them to a pluggable **streamer**. By default, MLIR integrates with LLVM’s
+[`llvm::remarks`](https://llvm.org/docs/Remarks.html), allowing you to:
 
-- **Opt-in**: Disabled by default; zero overhead unless enabled.
-- **Per-context**: Configured on `MLIRContext`.
-- **Formats**: LLVM’s Remark engine (YAML / Bitstream), or pluggable custom streamers.
-- **Kinds**: `Passed`, `Missed`, `Failure`, `Analysis`.
-- **API**: Lightweight streaming interface with `<<` (similar to diagnostics).
+- Stream remarks as passes run
+- Serialize them to **YAML** or **LLVM bitstream** for tooling
 
-## How it works
+______________________________________________________________________
 
-Remarks has two important classes:
+## Key Points
 
-- **`RemarkEngine`** (owned by `MLIRContext`): receives finalized
-  `InFlightRemark`s, optionally mirrors them to the `DiagnosticEngine`, then
+- **Opt-in** – Disabled by default; zero overhead unless enabled.
+- **Per-context** – Configured on `MLIRContext`.
+- **Formats** – LLVM Remark engine (YAML / Bitstream) or custom streamers.
+- **Kinds** – `Passed`, `Missed`, `Failure`, `Analysis`.
+- **API** – Lightweight streaming interface using `<<` (like MLIR diagnostics).
+
+______________________________________________________________________
+
+## How It Works
+
+Two main components:
+
+- **`RemarkEngine`** (owned by `MLIRContext`): Receives finalized
+  `InFlightRemark`s, optionally mirrors them to the `DiagnosticEngine`, and
   dispatches to the installed streamer.
-- **`MLIRRemarkStreamerBase`** (abstract): backend interface with a single hook
-  `streamOptimizationRemark(const Remark &)`.
 
-**Default backend – `MLIRLLVMRemarkStreamer`** Adapts `mlir::Remark` to
-`llvm::remarks::detail::Remark` and writes YAML/bitstream via
-`llvm::remarks::detail::RemarkStreamer` to a `ToolOutputFile`.
+- **`MLIRRemarkStreamerBase`** (abstract): Backend interface with a single hook:
+
+  ```c++
+  virtual void streamOptimizationRemark(const Remark &remark) = 0;
+  ```
+
+**Default backend – `MLIRLLVMRemarkStreamer`** Adapts `mlir::Remark` to LLVM’s
+remark format and writes YAML/bitstream via `llvm::remarks::RemarkStreamer`.
 
-**Ownership**: `MLIRContext` → `RemarkEngine` → `MLIRRemarkStreamerBase`.
+**Ownership flow:** `MLIRContext` → `RemarkEngine` → `MLIRRemarkStreamerBase`
+
+______________________________________________________________________
 
 ## Categories
 
-There are four built-in categories; you can extend these if needed.
+MLIR provides four built-in remark categories (extendable if needed):
 
-### Passed
+#### 1. **Passed**
 
-A diagnostic indicating the optimization/transformation succeeded.
+Optimization/transformation succeeded.
 
 ```c++
 [Passed] Vectorizer:myPass1 {Remark=vectorized loop, tripCount=128}
 ```
 
-### Missed
+#### 2. **Missed**
 
-A diagnostic indicating the optimization/transformation did not apply, ideally
-with actionable feedback.
+Optimization/transformation didn’t apply — ideally with actionable feedback.
 
 ```c++
 [Missed] Unroll: {Reason=tripCount=4 < threshold=256, Suggestion=increase unroll to 128}
 ```
 
-### Failure
+#### 3. **Failure**
 
-A diagnostic indicating the optimization/transformation attempted but failed (or
-could not run).
+Optimization/transformation attempted but failed (or could not run).
 
 ```c++
 [Failure] Unroll: {Reason=failed due to unsupported pattern}
 ```
 
-### Analysis
+#### 4. **Analysis**
 
-A diagnostic reporting analysis results.
+Neutral analysis results.
 
 ```c++
 [Analysis] Register: {Remark=Kernel uses 168 registers}
 [Analysis] Register: {Remark=Kernel uses 10kB local memory}
 ```
 
-## Enable Remarks via mlir::emitRemarks (No Streamer)
-
-Enable once per `MLIRContext` (e.g., where you build your pass pipeline or in
-your tool). If `printAsEmitRemarks` is true, each remark is also mirrored to the
-context’s `DiagnosticEngine` under the provided category labels—handy for
-interactive tools and tests.
-
-```c++
-mlir::remark::RemarkCategories cats{/*passed=*/categoryLoopunroll,
-                                          /*missed=*/std::nullopt,
-                                          /*analysis=*/std::nullopt,
-                                          /*failed=*/categoryLoopunroll};
-
-context.enableOptimizationRemarks(/*streamer=*/nullptr,
-                                  cats,
-                                  /*printAsEmitRemarks=*/true);
-```
-
-## Enable Remarks with LLVMRemarkStreamer (YAML/Bitstream)
-
-If you want to persist remarks to a file in YAML or bitstream format, use
-`mlir::remark::LLVMRemarkStreamer` (helper shown below):
-
-You can read more information about
-[LLVM's Remark from here](https://llvm.org/docs/Remarks.html).
-
-```c++
-#include "mlir/Remark/RemarkStreamer.h"
-
-mlir::remark::RemarkCategories cats{/*passed=*/categoryLoopunroll,
-                                         /*missed=*/std::nullopt,
-                                         /*analysis=*/std::nullopt,
-                                         /*failed=*/categoryLoopunroll};
-
-mlir::remark::enableOptimizationRemarksToFile(
-    context, yamlFile, llvm::remarks::Format::YAML, cats);
-```
+______________________________________________________________________
 
-## Emitting remarks from a pass
+## Emitting Remarks
 
-The `reportOptimization*` functions return an in-flight remark object (like MLIR
-diagnostics). Append strings and key–value pairs with `<<`.
+The `remark::*` helpers return an **in-flight remark**. You append strings or
+key–value metrics with `<<`.
 
 ```c++
 #include "mlir/IR/Remarks.h"
 
-using namespace mlir;
-
 LogicalResult MyPass::runOnOperation() {
-  Operation *op = getOperation();
-  Location loc = op->getLoc();
-
-  // PASS: something succeeded
-   remark::passed(loc, categoryVectorizer, myPassname1)
-        << "vectorized loop" << remark::metric("tripCount", 128);
+  Location loc = getOperation()->getLoc();
 
-  // ANALYSIS: neutral insight
-  remark::analysis(loc, categoryRegister, "") << "Kernel uses 168 registers";
+  // PASS
+  remark::passed(loc, categoryVectorizer, myPassname1)
+      << "vectorized loop"
+      << remark::metric("tripCount", 128);
 
-  // MISSED: explain why + suggest a fix
-  int target = 128;
-  int tripBad = 4;
-  int threshold = 256;
-  remark::missed(loc, categoryUnroll)
-      << remark::reason("tripCount={0} < threshold={1}", tripBad, threshold);
+  // ANALYSIS
+  remark::analysis(loc, categoryRegister, "")
+      << "Kernel uses 168 registers";
 
+  // MISSED (reason + suggestion)
+  int tripBad = 4, threshold = 256, target = 128;
   remark::missed(loc, categoryUnroll)
       << remark::reason("tripCount={0} < threshold={1}", tripBad, threshold)
       << remark::suggest("increase unroll to {0}", target);
 
-  // FAILURE: action attempted but failed
+  // FAILURE
   remark::failed(loc, categoryUnroll)
       << remark::reason("failed due to unsupported pattern");
 
@@ -149,11 +120,36 @@ LogicalResult MyPass::runOnOperation() {
 }
 ```
 
-### Output formats
+______________________________________________________________________
+
+### Metrics and Shortcuts
+
+- **`remark::metric(key, value)`** – Adds a structured key–value metric.
+- **`remark::reason(fmt, ...)`** – Shortcut for `metric("Reason", ...)`.
+- **`remark::suggest(fmt, ...)`** – Shortcut for `metric("Suggestion", ...)`.
+
+If you pass a plain string (e.g. `<< "vectorized loop"`), it’s equivalent to
+`metric("Remark", "vectorized loop")`.
+
+______________________________________________________________________
+
+## Enabling Remarks
+
+### 1. **With LLVMRemarkStreamer (YAML or Bitstream)**
+
+Persists remarks to a file in the chosen format.
+
+```c++
+mlir::remark::RemarkCategories cats{/*passed=*/categoryLoopunroll,
+                                     /*missed=*/std::nullopt,
+                                     /*analysis=*/std::nullopt,
+                                     /*failed=*/categoryLoopunroll};
 
-#### YAML
+mlir::remark::enableOptimizationRemarksToFile(
+    context, yamlFile, llvm::remarks::Format::YAML, cats);
+```
 
-Readable, easy to diff and grep.
+**YAML format** – human-readable, easy to diff:
 
 ```yaml
 --- !Passed
@@ -162,33 +158,47 @@ name:            vectorizer
 function:        myFunc
 loc:             myfile.mlir:12:3
 args:
-  - key:         tripCount
-    value:       128
-message:         "vectorized loop with tripCount=128"
+  - Remark:          vectorized loop
+  - tripCount:       128
 ```
 
-#### Bitstream
+**Bitstream format** – compact binary for large runs.
+
+______________________________________________________________________
+
+### 2. **With `mlir::emitRemarks` (No Streamer)**
+
+If the streamer isn't passed, the remarks are mirrored to the `DiagnosticEngine`
+using `mlir::emitRemarks`
+
+```c++
+mlir::remark::RemarkCategories cats{/*passed=*/categoryLoopunroll,
+                                     /*missed=*/std::nullopt,
+                                     /*analysis=*/std::nullopt,
+                                     /*failed=*/categoryLoopunroll};
+
+context.enableOptimizationRemarks(
+    /*streamer=*/nullptr, cats,
+    /*printAsEmitRemarks=*/true);
+```
 
-Compact binary format supported by LLVM’s remark tooling. Prefer this for large
-production runs or when existing infrastructure already consumes LLVM remarks.
+______________________________________________________________________
 
-## Enable Remarks with a Custom Streamer
+### 3. **With a Custom Streamer**
 
-`RemarkEngine` talks to `MLIRRemarkStreamerBase`. Implement your own streamer to
-consume remarks in any format you like:
+You can implement a custom streamer by inheriting `MLIRRemarkStreamerBase` to
+consume remarks in any format.
 
 ```c++
 class MyStreamer : public MLIRRemarkStreamerBase {
 public:
   void streamOptimizationRemark(const Remark &remark) override {
-    // Convert Remark to your format and write it out.
+    // Convert and write remark to your custom format
   }
 };
 
-// ...
 auto myStreamer = std::make_unique<MyStreamer>();
-context.setupOptimizationRemarks(path,
-                                 std::move(myStreamer),
+context.setupOptimizationRemarks(path, std::move(myStreamer),
                                  /*printAsEmitRemarks=*/false,
-                                 /*categories=*/cat);
+                                 /*categories=*/cats);
 ```

>From 77da6edd9b3d9760606bb104cfd947e32249a05d Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Thu, 14 Aug 2025 09:43:22 +0000
Subject: [PATCH 17/22] address @joker-eph  comments

---
 mlir/include/mlir/IR/MLIRContext.h | 22 +++-------------------
 mlir/include/mlir/IR/Remarks.h     | 17 ++++++++++++++++-
 mlir/lib/IR/MLIRContext.cpp        | 16 ----------------
 mlir/lib/IR/Remarks.cpp            | 17 +++++++++++++++++
 mlir/lib/Remark/RemarkStreamer.cpp |  5 +++--
 mlir/unittests/IR/RemarkTest.cpp   |  6 +++---
 6 files changed, 42 insertions(+), 41 deletions(-)

diff --git a/mlir/include/mlir/IR/MLIRContext.h b/mlir/include/mlir/IR/MLIRContext.h
index 6c3aac418fa79..ef22dc6fcb3ee 100644
--- a/mlir/include/mlir/IR/MLIRContext.h
+++ b/mlir/include/mlir/IR/MLIRContext.h
@@ -34,11 +34,7 @@ class MLIRContextImpl;
 class RegisteredOperationName;
 class StorageUniquer;
 class IRUnit;
-namespace remark {
-struct RemarkCategories;
-}
 namespace remark::detail {
-class MLIRRemarkStreamerBase;
 class RemarkEngine;
 } // namespace remark::detail
 
@@ -222,6 +218,9 @@ class MLIRContext {
   /// Returns the remark engine for this context.
   remark::detail::RemarkEngine *getRemarkEngine();
 
+  /// Set the remark engine for this context.
+  void setRemarkEngine(std::unique_ptr<remark::detail::RemarkEngine> engine);
+
   /// Returns the storage uniquer used for creating affine constructs.
   StorageUniquer &getAffineUniquer();
 
@@ -255,18 +254,6 @@ class MLIRContext {
   /// (attributes, operations, types, etc.).
   llvm::hash_code getRegistryHash();
 
-  /// Setup remarks for the context. This function will enable the remark engine
-  /// and set the streamer to be used for optimization remarks.
-  /// The remark categories are used to filter the remarks that will be emitted
-  /// by the remark engine. If a category is not specified, it will not be
-  /// emitted. If `printAsEmitRemarks` is true, the remarks will be printed as
-  /// mlir::emitRemarks.
-  /// 'streamer' must inherit from MLIRRemarkStreamerBase and will be used to
-  /// stream the remarks.
-  LogicalResult enableOptimizationRemarks(
-      std::unique_ptr<remark::detail::MLIRRemarkStreamerBase> streamer,
-      const remark::RemarkCategories &cats, bool printAsEmitRemarks = false);
-
   //===--------------------------------------------------------------------===//
   // Action API
   //===--------------------------------------------------------------------===//
@@ -303,9 +290,6 @@ class MLIRContext {
   }
 
 private:
-  /// Set the remark engine for this context.
-  void setRemarkEngine(std::unique_ptr<remark::detail::RemarkEngine> engine);
-
   /// Return true if the given dialect is currently loading.
   bool isDialectLoading(StringRef dialectNamespace);
 
diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index 7ba7a190324e4..e80eff44abced 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -213,7 +213,9 @@ struct LazyTextBuild {
 /// Similar to InFlightDiagnostic, but for remarks.
 class InFlightRemark {
 public:
-  explicit InFlightRemark(Remark *diag) : remark(diag) {}
+  explicit InFlightRemark(std::unique_ptr<Remark> diag)
+      : remark(std::move(diag)) {}
+
   InFlightRemark(RemarkEngine &eng, std::unique_ptr<Remark> diag)
       : owner(&eng), remark(std::move(diag)) {}
 
@@ -429,6 +431,19 @@ inline detail::InFlightRemark analysis(Location loc, StringRef cat,
                     passName, cat);
 }
 
+/// Setup remarks for the context. This function will enable the remark engine
+/// and set the streamer to be used for optimization remarks.
+/// The remark categories are used to filter the remarks that will be emitted
+/// by the remark engine. If a category is not specified, it will not be
+/// emitted. If `printAsEmitRemarks` is true, the remarks will be printed as
+/// mlir::emitRemarks.
+/// 'streamer' must inherit from MLIRRemarkStreamerBase and will be used to
+/// stream the remarks.
+LogicalResult enableOptimizationRemarks(
+    MLIRContext &ctx,
+    std::unique_ptr<remark::detail::MLIRRemarkStreamerBase> streamer,
+    const remark::RemarkCategories &cats, bool printAsEmitRemarks = false);
+
 } // namespace mlir::remark
 
 #endif // MLIR_IR_REMARKS_H
diff --git a/mlir/lib/IR/MLIRContext.cpp b/mlir/lib/IR/MLIRContext.cpp
index 0f68af77a598b..802ca74616998 100644
--- a/mlir/lib/IR/MLIRContext.cpp
+++ b/mlir/lib/IR/MLIRContext.cpp
@@ -32,7 +32,6 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
-#include "llvm/Support/Error.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Mutex.h"
 #include "llvm/Support/RWMutex.h"
@@ -408,21 +407,6 @@ remark::detail::RemarkEngine *MLIRContext::getRemarkEngine() {
   return getImpl().remarkEngine.get();
 }
 
-LogicalResult MLIRContext::enableOptimizationRemarks(
-    std::unique_ptr<remark::detail::MLIRRemarkStreamerBase> streamer,
-    const remark::RemarkCategories &cats, bool printAsEmitRemarks) {
-  auto engine =
-      std::make_unique<remark::detail::RemarkEngine>(printAsEmitRemarks, cats);
-
-  std::string errMsg;
-  if (failed(engine->initialize(std::move(streamer), &errMsg))) {
-    llvm::report_fatal_error(
-        llvm::Twine("Failed to initialize remark engine. Error: ") + errMsg);
-  }
-  setRemarkEngine(std::move(engine));
-  return success();
-}
-
 //===----------------------------------------------------------------------===//
 // Dialect and Operation Registration
 //===----------------------------------------------------------------------===//
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
index abc042d0e4cb3..cab57b66ab439 100644
--- a/mlir/lib/IR/Remarks.cpp
+++ b/mlir/lib/IR/Remarks.cpp
@@ -243,3 +243,20 @@ RemarkEngine::RemarkEngine(bool printAsEmitRemarks,
   if (cats.failed)
     failedFilter = llvm::Regex(cats.failed.value());
 }
+
+llvm::LogicalResult mlir::remark::enableOptimizationRemarks(
+    MLIRContext &ctx,
+    std::unique_ptr<remark::detail::MLIRRemarkStreamerBase> streamer,
+    const remark::RemarkCategories &cats, bool printAsEmitRemarks) {
+  auto engine =
+      std::make_unique<remark::detail::RemarkEngine>(printAsEmitRemarks, cats);
+
+  std::string errMsg;
+  if (failed(engine->initialize(std::move(streamer), &errMsg))) {
+    llvm::report_fatal_error(
+        llvm::Twine("Failed to initialize remark engine. Error: ") + errMsg);
+  }
+  ctx.setRemarkEngine(std::move(engine));
+
+  return success();
+}
diff --git a/mlir/lib/Remark/RemarkStreamer.cpp b/mlir/lib/Remark/RemarkStreamer.cpp
index e862543b682fe..0fe058cf102b3 100644
--- a/mlir/lib/Remark/RemarkStreamer.cpp
+++ b/mlir/lib/Remark/RemarkStreamer.cpp
@@ -62,8 +62,9 @@ LogicalResult enableOptimizationRemarksToFile(MLIRContext &ctx, StringRef path,
       detail::LLVMRemarkStreamer::createToFile(path, fmt);
   if (failed(sOr))
     return failure();
-  return ctx.enableOptimizationRemarks(std::move(*sOr), cat,
-                                       printAsEmitRemarks);
+
+  return remark::enableOptimizationRemarks(ctx, std::move(*sOr), cat,
+                                           printAsEmitRemarks);
 }
 
 } // namespace mlir::remark
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index 027d9c694097e..b04afeffef37a 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -174,7 +174,7 @@ TEST(Remark, TestOutputOptimizationRemarkDiagnostic) {
                                         /*failed=*/categoryUnroll};
 
     LogicalResult isEnabled =
-        context.enableOptimizationRemarks(nullptr, cats, true);
+        remark::enableOptimizationRemarks(context, nullptr, cats, true);
 
     ASSERT_TRUE(succeeded(isEnabled)) << "Failed to enable remark engine";
 
@@ -246,8 +246,8 @@ TEST(Remark, TestCustomOptimizationRemarkDiagnostic) {
                                         /*analysis=*/std::nullopt,
                                         /*failed=*/categoryLoopunroll};
 
-    LogicalResult isEnabled = context.enableOptimizationRemarks(
-        std::make_unique<MyCustomStreamer>(), cats, true);
+    LogicalResult isEnabled = remark::enableOptimizationRemarks(
+        context, std::make_unique<MyCustomStreamer>(), cats, true);
     ASSERT_TRUE(succeeded(isEnabled)) << "Failed to enable remark engine";
 
     // Remark 1: pass, category LoopUnroll

>From e11388645aa07e3a8f42f2ecffb9f8b0513c9414 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Thu, 14 Aug 2025 09:58:41 +0000
Subject: [PATCH 18/22] Improve document for Failure

---
 mlir/docs/Remarks.md | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/mlir/docs/Remarks.md b/mlir/docs/Remarks.md
index 35fc2eadcd793..870b74dd2f7e4 100644
--- a/mlir/docs/Remarks.md
+++ b/mlir/docs/Remarks.md
@@ -69,10 +69,19 @@ Optimization/transformation didn’t apply — ideally with actionable feedback.
 
 #### 3. **Failure**
 
-Optimization/transformation attempted but failed (or could not run).
+Optimization/transformation attempted but failed. This is slightly different
+from the `Missed` category.
+
+For example, the user specifies `-use-max-register=100` when invoking the
+compiler, but the attempt fails for some reason:
+
+```bash
+$ your-compiler -use-max-register=100 mycode.xyz
+```
 
 ```c++
-[Failure] Unroll: {Reason=failed due to unsupported pattern}
+[Failed]  { Limiting to use-max-register=100 failed;
+            ; it now uses 104 registers for better performance ... }
 ```
 
 #### 4. **Analysis**

>From 39d4fff50a1ae64d1d6feb255ebcf258d11590e8 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Thu, 14 Aug 2025 10:01:38 +0000
Subject: [PATCH 19/22] Set better API for
 enableOptimizationRemarksWithLLVMStreamer

---
 mlir/docs/Remarks.md                      | 2 +-
 mlir/include/mlir/Remark/RemarkStreamer.h | 7 +++----
 mlir/lib/Remark/RemarkStreamer.cpp        | 7 +++----
 mlir/unittests/IR/RemarkTest.cpp          | 5 +++--
 4 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/mlir/docs/Remarks.md b/mlir/docs/Remarks.md
index 870b74dd2f7e4..2f1210ed36fa5 100644
--- a/mlir/docs/Remarks.md
+++ b/mlir/docs/Remarks.md
@@ -154,7 +154,7 @@ mlir::remark::RemarkCategories cats{/*passed=*/categoryLoopunroll,
                                      /*analysis=*/std::nullopt,
                                      /*failed=*/categoryLoopunroll};
 
-mlir::remark::enableOptimizationRemarksToFile(
+mlir::remark::enableOptimizationRemarksWithLLVMStreamer(
     context, yamlFile, llvm::remarks::Format::YAML, cats);
 ```
 
diff --git a/mlir/include/mlir/Remark/RemarkStreamer.h b/mlir/include/mlir/Remark/RemarkStreamer.h
index 148629223b530..c98cfd4fc83c9 100644
--- a/mlir/include/mlir/Remark/RemarkStreamer.h
+++ b/mlir/include/mlir/Remark/RemarkStreamer.h
@@ -43,9 +43,8 @@ namespace mlir::remark {
 /// The remark categories are used to filter the remarks that are emitted.
 /// If the printAsEmitRemarks flag is set, remarks will also be printed using
 /// mlir::emitRemarks.
-LogicalResult enableOptimizationRemarksToFile(MLIRContext &ctx, StringRef path,
-                                              llvm::remarks::Format fmt,
-                                              const RemarkCategories &cat,
-                                              bool printAsEmitRemarks = false);
+LogicalResult enableOptimizationRemarksWithLLVMStreamer(
+    MLIRContext &ctx, StringRef filePath, llvm::remarks::Format fmt,
+    const RemarkCategories &cat, bool printAsEmitRemarks = false);
 
 } // namespace mlir::remark
diff --git a/mlir/lib/Remark/RemarkStreamer.cpp b/mlir/lib/Remark/RemarkStreamer.cpp
index 0fe058cf102b3..ceeb2c5e21d4a 100644
--- a/mlir/lib/Remark/RemarkStreamer.cpp
+++ b/mlir/lib/Remark/RemarkStreamer.cpp
@@ -53,10 +53,9 @@ LLVMRemarkStreamer::~LLVMRemarkStreamer() {
 } // namespace mlir::remark::detail
 
 namespace mlir::remark {
-LogicalResult enableOptimizationRemarksToFile(MLIRContext &ctx, StringRef path,
-                                              llvm::remarks::Format fmt,
-                                              const RemarkCategories &cat,
-                                              bool printAsEmitRemarks) {
+LogicalResult enableOptimizationRemarksWithLLVMStreamer(
+    MLIRContext &ctx, StringRef path, llvm::remarks::Format fmt,
+    const RemarkCategories &cat, bool printAsEmitRemarks) {
 
   FailureOr<std::unique_ptr<detail::MLIRRemarkStreamerBase>> sOr =
       detail::LLVMRemarkStreamer::createToFile(path, fmt);
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index b04afeffef37a..3b73d87f25ca9 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -51,8 +51,9 @@ TEST(Remark, TestOutputOptimizationRemark) {
                                         /*analysis=*/categoryRegister,
                                         /*failed=*/categoryUnroll};
 
-    LogicalResult isEnabled = mlir::remark::enableOptimizationRemarksToFile(
-        context, yamlFile, llvm::remarks::Format::YAML, cats);
+    LogicalResult isEnabled =
+        mlir::remark::enableOptimizationRemarksWithLLVMStreamer(
+            context, yamlFile, llvm::remarks::Format::YAML, cats);
     ASSERT_TRUE(succeeded(isEnabled)) << "Failed to enable remark engine";
 
     // PASS: something succeeded

>From c6970b9f08e7d58c123dbceeafa6ce3393ab9add Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Thu, 14 Aug 2025 14:04:37 +0000
Subject: [PATCH 20/22] few fixes

---
 mlir/docs/Remarks.md                      | 9 ++++-----
 mlir/include/mlir/IR/Remarks.h            | 3 +++
 mlir/include/mlir/Remark/RemarkStreamer.h | 3 +--
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/mlir/docs/Remarks.md b/mlir/docs/Remarks.md
index 2f1210ed36fa5..b02b3825db850 100644
--- a/mlir/docs/Remarks.md
+++ b/mlir/docs/Remarks.md
@@ -185,8 +185,7 @@ mlir::remark::RemarkCategories cats{/*passed=*/categoryLoopunroll,
                                      /*missed=*/std::nullopt,
                                      /*analysis=*/std::nullopt,
                                      /*failed=*/categoryLoopunroll};
-
-context.enableOptimizationRemarks(
+remark::enableOptimizationRemarks(
     /*streamer=*/nullptr, cats,
     /*printAsEmitRemarks=*/true);
 ```
@@ -207,7 +206,7 @@ public:
 };
 
 auto myStreamer = std::make_unique<MyStreamer>();
-context.setupOptimizationRemarks(path, std::move(myStreamer),
-                                 /*printAsEmitRemarks=*/false,
-                                 /*categories=*/cats);
+remark::enableOptimizationRemarks(
+    /*streamer=*/myStreamer, cats,
+    /*printAsEmitRemarks=*/true);
 ```
diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index e80eff44abced..94ca5353755ed 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -25,6 +25,9 @@
 #include "mlir/IR/Value.h"
 
 namespace mlir::remark {
+/// Define an the set of categories to accept.
+/// By default none are, the provided regex matches against
+/// the category names for each kind of remark.
 struct RemarkCategories {
   std::optional<std::string> passed, missed, analysis, failed;
 };
diff --git a/mlir/include/mlir/Remark/RemarkStreamer.h b/mlir/include/mlir/Remark/RemarkStreamer.h
index c98cfd4fc83c9..8bfd176d9bade 100644
--- a/mlir/include/mlir/Remark/RemarkStreamer.h
+++ b/mlir/include/mlir/Remark/RemarkStreamer.h
@@ -1,5 +1,4 @@
-//===- RemarkStreamer.h - MLIR Optimization Remark ----------------------*-
-// C++-*-===//
+//===- RemarkStreamer.h - MLIR Optimization Remark ---------------*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.

>From 219308fd55ed70bbc5417f43185683a9ee23f419 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Thu, 14 Aug 2025 15:22:58 +0000
Subject: [PATCH 21/22] add LLVM_UNLIKELY

---
 mlir/include/mlir/IR/Remarks.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index 94ca5353755ed..fc518c4d69733 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -374,7 +374,7 @@ inline InFlightRemark withEngine(Fn fn, Location loc, Args &&...args) {
 
   RemarkEngine *enginePtr = ctx->getRemarkEngine();
 
-  if (enginePtr)
+  if (LLVM_UNLIKELY(enginePtr))
     return (enginePtr->*fn)(loc, std::forward<Args>(args)...);
 
   return {};

>From c3be28a05178eabb17fdc10d1accd59cd7286409 Mon Sep 17 00:00:00 2001
From: Guray Ozen <gozen at nvidia.com>
Date: Fri, 15 Aug 2025 13:03:54 +0000
Subject: [PATCH 22/22] address comments

---
 mlir/docs/Remarks.md             |  5 ++-
 mlir/include/mlir/IR/Remarks.h   | 57 +++++++++++++++++++++-----------
 mlir/lib/IR/Remarks.cpp          |  4 +--
 mlir/unittests/IR/RemarkTest.cpp |  2 ++
 4 files changed, 43 insertions(+), 25 deletions(-)

diff --git a/mlir/docs/Remarks.md b/mlir/docs/Remarks.md
index b02b3825db850..bbe72b45ff3be 100644
--- a/mlir/docs/Remarks.md
+++ b/mlir/docs/Remarks.md
@@ -64,7 +64,7 @@ Optimization/transformation succeeded.
 Optimization/transformation didn’t apply — ideally with actionable feedback.
 
 ```c++
-[Missed] Unroll: {Reason=tripCount=4 < threshold=256, Suggestion=increase unroll to 128}
+[Missed] Unroll: {Reason=tripCount is 4 smaller than the threshold=256, Suggestion=Reduce threshold to 4}
 ```
 
 #### 3. **Failure**
@@ -80,8 +80,7 @@ $ your-compiler -use-max-register=100 mycode.xyz
 ```
 
 ```c++
-[Failed]  { Limiting to use-max-register=100 failed;
-            ; it now uses 104 registers for better performance ... }
+[Failed]  {Remark=Limiting to use-max-register=100 failed; it now uses 104 registers for better performance ... }
 ```
 
 #### 4. **Analysis**
diff --git a/mlir/include/mlir/IR/Remarks.h b/mlir/include/mlir/IR/Remarks.h
index fc518c4d69733..db3ddfb7dd44c 100644
--- a/mlir/include/mlir/IR/Remarks.h
+++ b/mlir/include/mlir/IR/Remarks.h
@@ -25,20 +25,30 @@
 #include "mlir/IR/Value.h"
 
 namespace mlir::remark {
-/// Define an the set of categories to accept.
-/// By default none are, the provided regex matches against
-/// the category names for each kind of remark.
+/// Define an the set of categories to accept. By default none are, the provided
+/// regex matches against the category names for each kind of remark.
 struct RemarkCategories {
   std::optional<std::string> passed, missed, analysis, failed;
 };
 
-/// Defines different remark kinds that can be used to categorize remarks.
+/// Categories describe the outcome of an optimization, not the mechanics of
+/// emitting/serializing remarks.
 enum class RemarkKind {
   OptimizationRemarkUnknown = 0,
-  OptimizationRemarkPassed,   // Optimization remark that was passed.
-  OptimizationRemarkMissed,   // Optimization remark that was missed.
-  OptimizationRemarkFailure,  // Optimization failure remark.
-  OptimizationRemarkAnalysis, // Analysis remark that does not indicate a pass.
+
+  /// An optimization was applied.
+  OptimizationRemarkPassed,
+
+  /// A profitable optimization opportunity was found but not applied.
+  OptimizationRemarkMissed,
+
+  /// The compiler attempted the optimization but failed (e.g., legality
+  /// checks, or better opportunites).
+  OptimizationRemarkFailure,
+
+  /// Informational context (e.g., analysis numbers) without a pass/fail
+  /// outcome.
+  OptimizationRemarkAnalysis,
 };
 } // namespace mlir::remark
 
@@ -284,7 +294,7 @@ class RemarkEngine {
   /// reported.
   std::optional<llvm::Regex> missFilter;
   /// The category for passed optimization remarks.
-  std::optional<llvm::Regex> passFilter;
+  std::optional<llvm::Regex> passedFilter;
   /// The category for analysis remarks.
   std::optional<llvm::Regex> analysisFilter;
   /// The category for failed optimization remarks.
@@ -312,10 +322,10 @@ class RemarkEngine {
 
   /// Return true if any type of remarks are enabled for this pass.
   bool isAnyRemarkEnabled(StringRef categoryName) const {
-    return (isMissedOptRemarkEnabled(categoryName) ||
-            isPassedOptRemarkEnabled(categoryName) ||
-            isFailedOptRemarkEnabled(categoryName) ||
-            isAnalysisOptRemarkEnabled(categoryName));
+    return isMissedOptRemarkEnabled(categoryName) ||
+           isPassedOptRemarkEnabled(categoryName) ||
+           isFailedOptRemarkEnabled(categoryName) ||
+           isAnalysisOptRemarkEnabled(categoryName);
   }
 
   /// Emit a remark using the given maker function, which should return
@@ -384,16 +394,24 @@ inline InFlightRemark withEngine(Fn fn, Location loc, Args &&...args) {
 
 namespace mlir::remark {
 
+/// Create a Reason with llvm::formatv formatting.
 template <class... Ts>
 inline detail::LazyTextBuild reason(const char *fmt, Ts &&...ts) {
   return {"Reason", [=] { return llvm::formatv(fmt, ts...).str(); }};
 }
 
+/// Create a Suggestion with llvm::formatv formatting.
 template <class... Ts>
 inline detail::LazyTextBuild suggest(const char *fmt, Ts &&...ts) {
   return {"Suggestion", [=] { return llvm::formatv(fmt, ts...).str(); }};
 }
 
+/// Create a Remark with llvm::formatv formatting.
+template <class... Ts>
+inline detail::LazyTextBuild add(const char *fmt, Ts &&...ts) {
+  return {"Remark", [=] { return llvm::formatv(fmt, ts...).str(); }};
+}
+
 template <class V>
 inline detail::LazyTextBuild metric(StringRef key, V &&v) {
   using DV = std::decay_t<V>;
@@ -435,13 +453,12 @@ inline detail::InFlightRemark analysis(Location loc, StringRef cat,
 }
 
 /// Setup remarks for the context. This function will enable the remark engine
-/// and set the streamer to be used for optimization remarks.
-/// The remark categories are used to filter the remarks that will be emitted
-/// by the remark engine. If a category is not specified, it will not be
-/// emitted. If `printAsEmitRemarks` is true, the remarks will be printed as
-/// mlir::emitRemarks.
-/// 'streamer' must inherit from MLIRRemarkStreamerBase and will be used to
-/// stream the remarks.
+/// and set the streamer to be used for optimization remarks. The remark
+/// categories are used to filter the remarks that will be emitted by the remark
+/// engine. If a category is not specified, it will not be emitted. If
+/// `printAsEmitRemarks` is true, the remarks will be printed as
+/// mlir::emitRemarks. 'streamer' must inherit from MLIRRemarkStreamerBase and
+/// will be used to stream the remarks.
 LogicalResult enableOptimizationRemarks(
     MLIRContext &ctx,
     std::unique_ptr<remark::detail::MLIRRemarkStreamerBase> streamer,
diff --git a/mlir/lib/IR/Remarks.cpp b/mlir/lib/IR/Remarks.cpp
index cab57b66ab439..78a33efbe31ca 100644
--- a/mlir/lib/IR/Remarks.cpp
+++ b/mlir/lib/IR/Remarks.cpp
@@ -165,7 +165,7 @@ bool RemarkEngine::isMissedOptRemarkEnabled(StringRef categoryName) const {
 }
 
 bool RemarkEngine::isPassedOptRemarkEnabled(StringRef categoryName) const {
-  return passFilter && passFilter->match(categoryName);
+  return passedFilter && passedFilter->match(categoryName);
 }
 
 bool RemarkEngine::isAnalysisOptRemarkEnabled(StringRef categoryName) const {
@@ -235,7 +235,7 @@ RemarkEngine::RemarkEngine(bool printAsEmitRemarks,
                            const RemarkCategories &cats)
     : printAsEmitRemarks(printAsEmitRemarks) {
   if (cats.passed)
-    passFilter = llvm::Regex(cats.passed.value());
+    passedFilter = llvm::Regex(cats.passed.value());
   if (cats.missed)
     missFilter = llvm::Regex(cats.missed.value());
   if (cats.analysis)
diff --git a/mlir/unittests/IR/RemarkTest.cpp b/mlir/unittests/IR/RemarkTest.cpp
index 3b73d87f25ca9..698e9735f2c2f 100644
--- a/mlir/unittests/IR/RemarkTest.cpp
+++ b/mlir/unittests/IR/RemarkTest.cpp
@@ -203,6 +203,8 @@ TEST(Remark, TestOutputOptimizationRemarkDiagnostic) {
         << remark::reason("failed due to unsupported pattern");
   }
   // clang-format off
+  unsigned long expectedSize = 5;
+  ASSERT_EQ(seenMsg.size(), expectedSize);
   EXPECT_EQ(seenMsg[0], "[Passed] Vectorizer:myPass1 {Remark=vectorized loop, tripCount=128}");
   EXPECT_EQ(seenMsg[1], "[Analysis] Register: {Remark=Kernel uses 168 registers}");
   EXPECT_EQ(seenMsg[2], "[Missed] Unroll: {Reason=tripCount=4 < threshold=256}");



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