diff --git a/mlir/include/mlir/IR/Diagnostics.h b/mlir/include/mlir/IR/Diagnostics.h
index 924ffd6f248b..e58013052fa4 100644
--- a/mlir/include/mlir/IR/Diagnostics.h
+++ b/mlir/include/mlir/IR/Diagnostics.h
@@ -37,6 +37,7 @@ class DiagnosticEngine;
 class Identifier;
 struct LogicalResult;
 class MLIRContext;
+class Operation;
 class Type;
 
 namespace detail {
@@ -64,6 +65,7 @@ public:
     Attribute,
     Double,
     Integer,
+    Operation,
     String,
     Type,
     Unsigned,
@@ -90,6 +92,12 @@ public:
     return static_cast<int64_t>(opaqueVal);
   }
 
+  /// Returns this argument as an operation.
+  Operation &getAsOperation() const {
+    assert(getKind() == DiagnosticArgumentKind::Operation);
+    return *reinterpret_cast<Operation *>(opaqueVal);
+  }
+
   /// Returns this argument as a string.
   StringRef getAsString() const {
     assert(getKind() == DiagnosticArgumentKind::String);
@@ -132,6 +140,14 @@ private:
                                      sizeof(T) <= sizeof(uint64_t)>::type * = 0)
       : kind(DiagnosticArgumentKind::Unsigned), opaqueVal(uint64_t(val)) {}
 
+  // Construct from an operation reference.
+  explicit DiagnosticArgument(Operation &val) : DiagnosticArgument(&val) {}
+  explicit DiagnosticArgument(Operation *val)
+      : kind(DiagnosticArgumentKind::Operation),
+        opaqueVal(reinterpret_cast<intptr_t>(val)) {
+    assert(val && "expected valid operation");
+  }
+
   // Construct from a string reference.
   explicit DiagnosticArgument(StringRef val)
       : kind(DiagnosticArgumentKind::String), stringVal(val) {}
diff --git a/mlir/lib/IR/Diagnostics.cpp b/mlir/lib/IR/Diagnostics.cpp
index 5283cf086da3..194f427f4f42 100644
--- a/mlir/lib/IR/Diagnostics.cpp
+++ b/mlir/lib/IR/Diagnostics.cpp
@@ -20,6 +20,7 @@
 #include "mlir/IR/Identifier.h"
 #include "mlir/IR/Location.h"
 #include "mlir/IR/MLIRContext.h"
+#include "mlir/IR/Operation.h"
 #include "mlir/IR/Types.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringMap.h"
@@ -70,6 +71,9 @@ void DiagnosticArgument::print(raw_ostream &os) const {
   case DiagnosticArgumentKind::Integer:
     os << getAsInteger();
     break;
+  case DiagnosticArgumentKind::Operation:
+    os << getAsOperation();
+    break;
   case DiagnosticArgumentKind::String:
     os << getAsString();
     break;