diff --git a/clang/include/clang/CIR/LoweringHelpers.h b/clang/include/clang/CIR/LoweringHelpers.h
index 32f9f3b3a98b..483fde742934 100644
--- a/clang/include/clang/CIR/LoweringHelpers.h
+++ b/clang/include/clang/CIR/LoweringHelpers.h
@@ -50,4 +50,9 @@ lowerConstArrayAttr(cir::ConstArrayAttr constArr,
 std::optional<mlir::Attribute>
 lowerConstVectorAttr(cir::ConstVectorAttr constArr,
                      const mlir::TypeConverter *converter);
+
+std::optional<mlir::Attribute>
+lowerConstComplexAttr(cir::ComplexAttr constArr,
+                      const mlir::TypeConverter *converter);
+
 #endif
diff --git a/clang/lib/CIR/CodeGen/CIRGenExprConst.cpp b/clang/lib/CIR/CodeGen/CIRGenExprConst.cpp
index 1c34651318d3..426f6eb0411d 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprConst.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprConst.cpp
@@ -2007,9 +2007,30 @@ mlir::Attribute ConstantEmitter::tryEmitPrivate(const APValue &Value,
   case APValue::Struct:
   case APValue::Union:
     return ConstRecordBuilder::BuildRecord(*this, Value, DestType);
-  case APValue::FixedPoint:
-  case APValue::ComplexInt:
   case APValue::ComplexFloat:
+  case APValue::ComplexInt: {
+    mlir::Type desiredType = CGM.convertType(DestType);
+    cir::ComplexType complexType =
+        mlir::dyn_cast<cir::ComplexType>(desiredType);
+
+    mlir::Type complexElemTy = complexType.getElementType();
+    if (isa<cir::IntType>(complexElemTy)) {
+      llvm::APSInt real = Value.getComplexIntReal();
+      llvm::APSInt imag = Value.getComplexIntImag();
+      return builder.getAttr<cir::ComplexAttr>(
+          complexType, builder.getAttr<cir::IntAttr>(complexElemTy, real),
+          builder.getAttr<cir::IntAttr>(complexElemTy, imag));
+    }
+
+    assert(isa<cir::CIRFPTypeInterface>(complexElemTy) &&
+           "expected floating-point type");
+    llvm::APFloat real = Value.getComplexFloatReal();
+    llvm::APFloat imag = Value.getComplexFloatImag();
+    return builder.getAttr<cir::ComplexAttr>(
+        complexType, builder.getAttr<cir::FPAttr>(complexElemTy, real),
+        builder.getAttr<cir::FPAttr>(complexElemTy, imag));
+  }
+  case APValue::FixedPoint:
   case APValue::AddrLabelDiff:
     assert(0 && "not implemented");
   }
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 66dce5d80d08..604f5aba80ca 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -452,8 +452,8 @@ class CirAttrToValue {
         .Case<cir::IntAttr, cir::FPAttr, cir::ConstPtrAttr,
               cir::ConstRecordAttr, cir::ConstArrayAttr, cir::ConstVectorAttr,
               cir::BoolAttr, cir::ZeroAttr, cir::UndefAttr, cir::PoisonAttr,
-              cir::GlobalViewAttr, cir::VTableAttr, cir::TypeInfoAttr>(
-            [&](auto attrT) { return visitCirAttr(attrT); })
+              cir::GlobalViewAttr, cir::VTableAttr, cir::TypeInfoAttr,
+              cir::ComplexAttr>([&](auto attrT) { return visitCirAttr(attrT); })
         .Default([&](auto attrT) { return mlir::Value(); });
   }
 
@@ -463,6 +463,7 @@ class CirAttrToValue {
   mlir::Value visitCirAttr(cir::ConstRecordAttr attr);
   mlir::Value visitCirAttr(cir::ConstArrayAttr attr);
   mlir::Value visitCirAttr(cir::ConstVectorAttr attr);
+  mlir::Value visitCirAttr(cir::ComplexAttr attr);
   mlir::Value visitCirAttr(cir::BoolAttr attr);
   mlir::Value visitCirAttr(cir::ZeroAttr attr);
   mlir::Value visitCirAttr(cir::UndefAttr attr);
@@ -647,6 +648,33 @@ mlir::Value CirAttrToValue::visitCirAttr(cir::ConstVectorAttr constVec) {
                                    mlirValues));
 }
 
+mlir::Value CirAttrToValue::visitCirAttr(cir::ComplexAttr complexAttr) {
+  auto complexType = mlir::cast<cir::ComplexType>(complexAttr.getType());
+  mlir::Type complexElemTy = complexType.getElementType();
+  mlir::Type complexElemLLVMTy = converter->convertType(complexElemTy);
+
+  mlir::Attribute components[2];
+  if (const auto intType = mlir::dyn_cast<cir::IntType>(complexElemTy)) {
+    components[0] = rewriter.getIntegerAttr(
+        complexElemLLVMTy,
+        mlir::cast<cir::IntAttr>(complexAttr.getReal()).getValue());
+    components[1] = rewriter.getIntegerAttr(
+        complexElemLLVMTy,
+        mlir::cast<cir::IntAttr>(complexAttr.getImag()).getValue());
+  } else {
+    components[0] = rewriter.getFloatAttr(
+        complexElemLLVMTy,
+        mlir::cast<cir::FPAttr>(complexAttr.getReal()).getValue());
+    components[1] = rewriter.getFloatAttr(
+        complexElemLLVMTy,
+        mlir::cast<cir::FPAttr>(complexAttr.getImag()).getValue());
+  }
+
+  mlir::Location loc = parentOp->getLoc();
+  return rewriter.create<mlir::LLVM::ConstantOp>(
+      loc, converter->convertType(complexAttr.getType()),
+      rewriter.getArrayAttr(components));
+}
 // GlobalViewAttr visitor.
 mlir::Value CirAttrToValue::visitCirAttr(cir::GlobalViewAttr globalAttr) {
   auto module = parentOp->getParentOfType<mlir::ModuleOp>();
@@ -2428,6 +2456,9 @@ mlir::LogicalResult CIRToLLVMGlobalOpLowering::lowerInitializer(
   } else if (mlir::isa<cir::ConstVectorAttr>(init)) {
     return lowerInitializerForConstVector(rewriter, op, init,
                                           useInitializerRegion);
+  } else if (mlir::isa<cir::ComplexAttr>(init)) {
+    return lowerInitializerForConstComplex(rewriter, op, init,
+                                           useInitializerRegion);
   } else if (auto dataMemberAttr = mlir::dyn_cast<cir::DataMemberAttr>(init)) {
     assert(lowerMod && "lower module is not available");
     mlir::DataLayout layout(op->getParentOfType<mlir::ModuleOp>());
@@ -2464,6 +2495,19 @@ mlir::LogicalResult CIRToLLVMGlobalOpLowering::lowerInitializerForConstVector(
   return mlir::failure();
 }
 
+mlir::LogicalResult CIRToLLVMGlobalOpLowering::lowerInitializerForConstComplex(
+    mlir::ConversionPatternRewriter &rewriter, cir::GlobalOp op,
+    mlir::Attribute &init, bool &useInitializerRegion) const {
+  auto constVec = mlir::cast<cir::ComplexAttr>(init);
+  if (auto val = lowerConstComplexAttr(constVec, getTypeConverter());
+      val.has_value()) {
+    init = val.value();
+    useInitializerRegion = false;
+  } else
+    useInitializerRegion = true;
+  return mlir::success();
+}
+
 mlir::LogicalResult CIRToLLVMGlobalOpLowering::lowerInitializerForConstArray(
     mlir::ConversionPatternRewriter &rewriter, cir::GlobalOp op,
     mlir::Attribute &init, bool &useInitializerRegion) const {
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
index 74edf58b347a..ad3fa1983c38 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
@@ -628,6 +628,11 @@ class CIRToLLVMGlobalOpLowering
                                  cir::GlobalOp op, mlir::Attribute &init,
                                  bool &useInitializerRegion) const;
 
+  mlir::LogicalResult
+  lowerInitializerForConstComplex(mlir::ConversionPatternRewriter &rewriter,
+                                  cir::GlobalOp op, mlir::Attribute &init,
+                                  bool &useInitializerRegion) const;
+
   mlir::LogicalResult
   lowerInitializerDirect(mlir::ConversionPatternRewriter &rewriter,
                          cir::GlobalOp op, mlir::Type llvmType,
diff --git a/clang/lib/CIR/Lowering/LoweringHelpers.cpp b/clang/lib/CIR/Lowering/LoweringHelpers.cpp
index 1cfcc966e8a8..0dd209fdb6b9 100644
--- a/clang/lib/CIR/Lowering/LoweringHelpers.cpp
+++ b/clang/lib/CIR/Lowering/LoweringHelpers.cpp
@@ -126,6 +126,33 @@ void convertToDenseElementsAttrImpl(
   }
 }
 
+template <typename AttrTy, typename StorageTy>
+void convertToDenseElementsAttrImpl(
+    cir::ComplexAttr attr, llvm::SmallVectorImpl<StorageTy> &values,
+    const llvm::SmallVectorImpl<int64_t> &currentDims, int64_t dimIndex,
+    int64_t currentIndex) {
+  dimIndex++;
+  std::size_t elementsSizeInCurrentDim = 1;
+  for (std::size_t i = dimIndex; i < currentDims.size(); i++)
+    elementsSizeInCurrentDim *= currentDims[i];
+
+  auto attrArray =
+      mlir::ArrayAttr::get(attr.getContext(), {attr.getImag(), attr.getReal()});
+  for (auto eltAttr : attrArray) {
+    if (auto valueAttr = mlir::dyn_cast<AttrTy>(eltAttr)) {
+      values[currentIndex++] = valueAttr.getValue();
+      continue;
+    }
+
+    if (mlir::isa<cir::ZeroAttr, cir::UndefAttr>(eltAttr)) {
+      currentIndex += elementsSizeInCurrentDim;
+      continue;
+    }
+
+    llvm_unreachable("unknown element in ComplexAttr");
+  }
+}
+
 template <typename AttrTy, typename StorageTy>
 mlir::DenseElementsAttr convertToDenseElementsAttr(
     cir::ConstArrayAttr attr, const llvm::SmallVectorImpl<int64_t> &dims,
@@ -158,6 +185,20 @@ mlir::DenseElementsAttr convertToDenseElementsAttr(
       llvm::ArrayRef(values));
 }
 
+template <typename AttrTy, typename StorageTy>
+mlir::DenseElementsAttr convertToDenseElementsAttr(
+    cir::ComplexAttr attr, const llvm::SmallVectorImpl<int64_t> &dims,
+    mlir::Type elementType, mlir::Type convertedElementType) {
+  unsigned array_size = 2;
+  auto values = llvm::SmallVector<StorageTy, 8>(
+      array_size, getZeroInitFromType<StorageTy>(elementType));
+  convertToDenseElementsAttrImpl<AttrTy>(attr, values, dims, /*currentDim=*/0,
+                                         /*initialIndex=*/0);
+  return mlir::DenseElementsAttr::get(
+      mlir::RankedTensorType::get(dims, convertedElementType),
+      llvm::ArrayRef(values));
+}
+
 std::optional<mlir::Attribute>
 lowerConstArrayAttr(cir::ConstArrayAttr constArr,
                     const mlir::TypeConverter *converter) {
@@ -191,6 +232,27 @@ lowerConstArrayAttr(cir::ConstArrayAttr constArr,
   return std::nullopt;
 }
 
+std::optional<mlir::Attribute>
+lowerConstComplexAttr(cir::ComplexAttr constComplex,
+                      const mlir::TypeConverter *converter) {
+
+  // Ensure ComplexAttr has a type.
+  auto typedConstArr = mlir::dyn_cast<mlir::TypedAttr>(constComplex);
+  assert(typedConstArr && "cir::ComplexAttr is not a mlir::TypedAttr");
+
+  mlir::Type type = constComplex.getType();
+  auto dims = llvm::SmallVector<int64_t, 2>{2};
+
+  if (mlir::isa<cir::IntType>(type))
+    return convertToDenseElementsAttr<cir::IntAttr, mlir::APInt>(
+        constComplex, dims, type, converter->convertType(type));
+  if (mlir::isa<cir::CIRFPTypeInterface>(type))
+    return convertToDenseElementsAttr<cir::FPAttr, mlir::APFloat>(
+        constComplex, dims, type, converter->convertType(type));
+
+  return std::nullopt;
+}
+
 std::optional<mlir::Attribute>
 lowerConstVectorAttr(cir::ConstVectorAttr constArr,
                      const mlir::TypeConverter *converter) {
diff --git a/clang/test/CIR/CodeGen/const-complex.cpp b/clang/test/CIR/CodeGen/const-complex.cpp
new file mode 100644
index 000000000000..76b4f8a0284d
--- /dev/null
+++ b/clang/test/CIR/CodeGen/const-complex.cpp
@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -Wno-unused-value -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s -check-prefix=CHECK
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -Wno-unused-value -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --input-file=%t-cir.ll %s -check-prefix=LLVM
+
+int _Complex gci;
+
+float _Complex gcf;
+
+int _Complex gci2 = { 1, 2 };
+
+float _Complex gcf2 = { 1.0f, 2.0f };
+
+// CHECK: cir.global external {{.*}} = #cir.zero : !cir.complex<!s32i>
+// CHECK: cir.global external {{.*}} = #cir.zero : !cir.complex<!cir.float>
+// CHECK: cir.global external {{.*}} = #cir.complex<#cir.int<1> : !s32i, #cir.int<2> : !s32i> : !cir.complex<!s32i>
+// CHECK: cir.global external {{.*}} = #cir.complex<#cir.fp<1.000000e+00> : !cir.float, #cir.fp<2.000000e+00> : !cir.float> : !cir.complex<!cir.float>
+
+// LLVM: {{.*}} = global { i32, i32 } zeroinitializer, align 4
+// LLVM: {{.*}} = global { float, float } zeroinitializer, align 4
+// LLVM: {{.*}} = global { i32, i32 } { i32 1, i32 2 }, align 4
+// LLVM: {{.*}} = global { float, float } { float 1.000000e+00, float 2.000000e+00 }, align 4
\ No newline at end of file