diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
@@ -29,6 +29,15 @@
   let assemblyFormat = "`<` $CallingConv `>`";
 }
 
+//===----------------------------------------------------------------------===//
+// ComdatAttr
+//===----------------------------------------------------------------------===//
+
+def ComdatAttr : LLVM_Attr<"Comdat", "comdat"> {
+  let parameters = (ins "comdat::Comdat":$comdat);
+  let assemblyFormat = "$comdat";
+}
+
 //===----------------------------------------------------------------------===//
 // LinkageAttr
 //===----------------------------------------------------------------------===//
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrs.h b/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrs.h
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrs.h
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrs.h
@@ -66,6 +66,7 @@
 // TODO: this shouldn't be needed after we unify the attribute generation, i.e.
 // --gen-attr-* and --gen-attrdef-*.
 using cconv::CConv;
+using comdat::Comdat;
 using linkage::Linkage;
 } // namespace LLVM
 } // namespace mlir
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMEnums.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMEnums.td
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMEnums.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMEnums.td
@@ -589,6 +589,42 @@
           "::mlir::LLVM::LinkageAttr::get($_builder.getContext(), $0)";
 }
 
+
+//===----------------------------------------------------------------------===//
+// Comdat
+//===----------------------------------------------------------------------===//
+
+def ComdatAny
+    : LLVM_EnumAttrCase<"Any", "any", "Any", 0>;
+def ComdatExactMatch
+    : LLVM_EnumAttrCase<"ExactMatch", "exactmatch", "ExactMatch", 1>;
+def ComdatLargest
+    : LLVM_EnumAttrCase<"Largest", "largest", "Largest", 2>;
+def ComdatNoDeduplicate
+    : LLVM_EnumAttrCase<"NoDeduplicate", "nodeduplicate", "NoDeduplicate", 3>;
+def ComdatSameSize
+    : LLVM_EnumAttrCase<"SameSize", "samesize", "SameSize", 4>;
+
+def ComdatEnum : LLVM_EnumAttr<
+  "Comdat",
+  "::llvm::Comdat::SelectionKind",
+  "LLVM Comdat Types",
+  [ComdatAny, ComdatExactMatch, ComdatLargest,
+   ComdatNoDeduplicate, ComdatSameSize]> {
+  let cppNamespace = "::mlir::LLVM::comdat";
+}
+
+def Comdat : DialectAttr<
+  LLVM_Dialect,
+  CPred<"$_self.isa<::mlir::LLVM::ComdatAttr>()">,
+  "LLVM Comdat selection kind"> {
+  let storageType = "::mlir::LLVM::ComdatAttr";
+  let returnType = "::mlir::LLVM::Comdat";
+  let convertFromStorage = "$_self.getComdat()";
+  let constBuilderCall =
+          "::mlir::LLVM::ComdatAttr::get($_builder.getContext(), $0)";
+}
+
 //===----------------------------------------------------------------------===//
 // UnnamedAddr
 //===----------------------------------------------------------------------===//
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
@@ -1316,6 +1316,7 @@
     DefaultValuedAttr<ConfinedAttr<I32Attr, [IntNonNegative]>, "0">:$addr_space,
     OptionalAttr<UnnamedAddr>:$unnamed_addr,
     OptionalAttr<StrAttr>:$section,
+    OptionalAttr<StrAttr>:$comdat,
     DefaultValuedAttr<Visibility, "mlir::LLVM::Visibility::Default">:$visibility_
   );
   let summary = "LLVM dialect global.";
@@ -1424,6 +1425,7 @@
       CArg<"unsigned", "0">:$addrSpace,
       CArg<"bool", "false">:$dsoLocal,
       CArg<"bool", "false">:$thread_local_,
+      CArg<"std::optional<StringRef>", "std::nullopt">:$comdat,
       CArg<"ArrayRef<NamedAttribute>", "{}">:$attrs)>
   ];
 
@@ -1515,6 +1517,31 @@
   let hasVerifier = 1;
 }
 
+def LLVM_ComdatOp : LLVM_Op<"mlir.comdat", [Symbol]> {
+  let arguments = (ins
+    SymbolNameAttr:$sym_name,
+    Comdat:$comdat
+  );
+  let summary = "LLVM dialect comdat declaration";
+
+  let description = [{
+    Provides access to object file COMDAT section/group functionality.
+
+    Examples:
+    ```mlir
+    llvm.mlir.comdat @any_comdat any
+    llvm.mlir.global internal constant @has_any_comdat(1 : i64) comdat(@any_comdat) : i64
+    ```
+  }];
+
+  let assemblyFormat = "$sym_name $comdat attr-dict";
+  let llvmBuilder = [{
+    llvm::Module *module = moduleTranslation.getLLVMModule();
+    llvm::Comdat *comdat = module->getOrInsertComdat($sym_name);
+    comdat->setSelectionKind(convertComdatToLLVM($comdat));
+  }];
+}
+
 def LLVM_LLVMFuncOp : LLVM_Op<"func", [
     AutomaticAllocationScope, IsolatedFromAbove, FunctionOpInterface,
     CallableOpInterface
diff --git a/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp b/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
--- a/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
+++ b/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
@@ -38,6 +38,7 @@
 
 #include <numeric>
 #include <optional>
+#include <string_view>
 
 using namespace mlir;
 using namespace mlir::LLVM;
@@ -1601,6 +1602,7 @@
                      bool isConstant, Linkage linkage, StringRef name,
                      Attribute value, uint64_t alignment, unsigned addrSpace,
                      bool dsoLocal, bool threadLocal,
+                     std::optional<StringRef> comdat,
                      ArrayRef<NamedAttribute> attrs) {
   result.addAttribute(getSymNameAttrName(result.name),
                       builder.getStringAttr(name));
@@ -1616,6 +1618,9 @@
   if (threadLocal)
     result.addAttribute(getThreadLocal_AttrName(result.name),
                         builder.getUnitAttr());
+  if (comdat)
+    result.addAttribute(getComdatAttrName(result.name),
+                        builder.getStringAttr(*comdat));
 
   // Only add an alignment attribute if the "alignment" input
   // is different from 0. The value must also be a power of two, but
@@ -1652,6 +1657,9 @@
   if (auto value = getValueOrNull())
     p.printAttribute(value);
   p << ')';
+  if (auto cd = getComdat())
+    p << " comdat(@" << *cd << ')';
+
   // Note that the alignment attribute is printed using the
   // default syntax here, even though it is an inherent attribute
   // (as defined in https://mlir.llvm.org/docs/LangRef/#attributes)
@@ -1660,7 +1668,7 @@
                            getGlobalTypeAttrName(), getConstantAttrName(),
                            getValueAttrName(), getLinkageAttrName(),
                            getUnnamedAddrAttrName(), getThreadLocal_AttrName(),
-                           getVisibility_AttrName()});
+                           getVisibility_AttrName(), getComdatAttrName()});
 
   // Print the trailing type unless it's a string global.
   if (llvm::dyn_cast_or_null<StringAttr>(getValueOrNull()))
@@ -1768,6 +1776,15 @@
       return failure();
   }
 
+  if (succeeded(parser.parseOptionalKeyword("comdat"))) {
+    StringAttr comdat;
+    if (parser.parseLParen() ||
+        parser.parseSymbolName(comdat) || parser.parseRParen())
+      return failure();
+
+    result.addAttribute(getComdatAttrName(result.name), comdat);
+  }
+
   SmallVector<Type, 1> types;
   if (parser.parseOptionalAttrDict(result.attributes) ||
       parser.parseOptionalColonTypeList(types))
@@ -1850,6 +1867,12 @@
     }
   }
 
+  if(getComdat()) {
+    auto *op = SymbolTable::lookupNearestSymbolFrom(*this, getComdatAttr());
+    if (!llvm::isa_and_nonnull<ComdatOp>(op))
+      return emitOpError() << "expected comdat symbol";
+  }
+
   std::optional<uint64_t> alignAttr = getAlignment();
   if (alignAttr.has_value()) {
     uint64_t value = alignAttr.value();
diff --git a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
--- a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
@@ -714,6 +714,11 @@
                              : llvm::GlobalValue::NotThreadLocal,
         addrSpace);
 
+    if (auto comdat = op.getComdat()) {
+      auto *llcomdat = llvmModule->getOrInsertComdat(*comdat);
+      var->setComdat(llcomdat);
+    }
+
     if (op.getUnnamedAddr().has_value())
       var->setUnnamedAddr(convertUnnamedAddrToLLVM(*op.getUnnamedAddr()));
 
diff --git a/mlir/test/Dialect/LLVMIR/comdat.mlir b/mlir/test/Dialect/LLVMIR/comdat.mlir
new file mode 100644
--- /dev/null
+++ b/mlir/test/Dialect/LLVMIR/comdat.mlir
@@ -0,0 +1,12 @@
+// RUN: mlir-opt -split-input-file -verify-diagnostics %s | FileCheck %s
+
+// CHECK: llvm.mlir.comdat @any_comdat any
+llvm.mlir.comdat @any_comdat any
+// CHECK: llvm.mlir.comdat @exactmatch_comdat exactmatch
+llvm.mlir.comdat @exactmatch_comdat exactmatch
+// CHECK: llvm.mlir.comdat @largest_comdat largest
+llvm.mlir.comdat @largest_comdat largest
+// CHECK: llvm.mlir.comdat @nodeduplicate_comdat nodeduplicate
+llvm.mlir.comdat @nodeduplicate_comdat nodeduplicate
+// CHECK: llvm.mlir.comdat @samesize_comdat samesize
+llvm.mlir.comdat @samesize_comdat samesize
diff --git a/mlir/test/Dialect/LLVMIR/global.mlir b/mlir/test/Dialect/LLVMIR/global.mlir
--- a/mlir/test/Dialect/LLVMIR/global.mlir
+++ b/mlir/test/Dialect/LLVMIR/global.mlir
@@ -64,6 +64,11 @@
 // CHECK: llvm.mlir.global external @has_addr_space(32 : i64) {addr_space = 3 : i32} : i64
 llvm.mlir.global external @has_addr_space(32 : i64) {addr_space = 3: i32} : i64
 
+// CHECK: llvm.mlir.comdat @any_comdat any
+llvm.mlir.comdat @any_comdat any
+// CHECK: llvm.mlir.global external @any() comdat(@any_comdat) {addr_space = 0 : i32} : i64
+llvm.mlir.global @any() comdat(@any_comdat) : i64
+
 // CHECK-LABEL: references
 func.func @references() {
   // CHECK: llvm.mlir.addressof @".string" : !llvm.ptr
diff --git a/mlir/test/Target/LLVMIR/llvmir.mlir b/mlir/test/Target/LLVMIR/llvmir.mlir
--- a/mlir/test/Target/LLVMIR/llvmir.mlir
+++ b/mlir/test/Target/LLVMIR/llvmir.mlir
@@ -1,5 +1,19 @@
 // RUN: mlir-translate -mlir-to-llvmir -split-input-file %s | FileCheck %s
 
+
+// Comdat sections
+// CHECK: $any_comdat = comdat any
+llvm.mlir.comdat @any_comdat any
+// CHECK: $exactmatch_comdat = comdat exactmatch
+llvm.mlir.comdat @exactmatch_comdat exactmatch
+// CHECK: $largest_comdat = comdat largest
+llvm.mlir.comdat @largest_comdat largest
+// CHECK: $nodeduplicate_comdat = comdat nodeduplicate
+llvm.mlir.comdat @nodeduplicate_comdat nodeduplicate
+// CHECK: $samesize_comdat = comdat samesize
+llvm.mlir.comdat @samesize_comdat samesize
+
+
 // CHECK: @global_aligned32 = private global i64 42, align 32
 "llvm.mlir.global"() ({}) {sym_name = "global_aligned32", global_type = i64, value = 42 : i64, linkage = #llvm.linkage<private>, alignment = 32} : () -> ()
 
@@ -162,6 +176,20 @@
 // CHECK: @sectionvar = internal constant [10 x i8] c"teststring", section ".mysection"
 llvm.mlir.global internal constant @sectionvar("teststring")  {section = ".mysection"}: !llvm.array<10 x i8>
 
+//
+// Comdat attribute.
+//
+// CHECK: @has_any_comdat = internal constant i64 1, comdat($any_comdat)
+llvm.mlir.global internal constant @has_any_comdat(1 : i64) comdat(@any_comdat) : i64
+// CHECK: @has_exactmatch_comdat = internal constant i64 1, comdat($exactmatch_comdat)
+llvm.mlir.global internal constant @has_exactmatch_comdat(1 : i64) comdat(@exactmatch_comdat) : i64
+// CHECK: @has_largest_comdat = internal constant i64 1, comdat($largest_comdat)
+llvm.mlir.global internal constant @has_largest_comdat(1 : i64) comdat(@largest_comdat) : i64
+// CHECK: @has_nodeduplicate_comdat = internal constant i64 1, comdat($nodeduplicate_comdat)
+llvm.mlir.global internal constant @has_nodeduplicate_comdat(1 : i64) comdat(@nodeduplicate_comdat) : i64
+// CHECK: @has_samesize_comdat = internal constant i64 1, comdat($samesize_comdat)
+llvm.mlir.global internal constant @has_samesize_comdat(1 : i64) comdat(@samesize_comdat) : i64
+
 //
 // Declarations of the allocation functions to be linked against. These are
 // inserted before other functions in the module.