[clang] [CIR] Implement CXXScalarValueInitExpr for ComplexType (PR #147143)

[Amr Hesham via cfe-commits]

https://github.com/AmrDeveloper updated https://github.com/llvm/llvm-project/pull/147143

>From d8c01a7c98bea2440ab8b704501f7e3efb33549d Mon Sep 17 00:00:00 2001
From: AmrDeveloper <amr96 at programmer.net>
Date: Sat, 5 Jul 2025 14:27:21 +0200
Subject: [PATCH 1/2] [CIR] Implement CXXScalarValueInitExpr for ComplexType

---
 clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp | 12 ++++++++++++
 clang/test/CIR/CodeGen/complex.cpp          | 18 ++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp b/clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp
index c000b225f31f3..48024b457f848 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp
@@ -44,6 +44,7 @@ class ComplexExprEmitter : public StmtVisitor<ComplexExprEmitter, mlir::Value> {
   mlir::Value VisitBinComma(const BinaryOperator *e);
   mlir::Value VisitCallExpr(const CallExpr *e);
   mlir::Value VisitChooseExpr(ChooseExpr *e);
+  mlir::Value VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *e);
   mlir::Value VisitDeclRefExpr(DeclRefExpr *e);
   mlir::Value VisitGenericSelectionExpr(GenericSelectionExpr *e);
   mlir::Value VisitImplicitCastExpr(ImplicitCastExpr *e);
@@ -161,6 +162,17 @@ mlir::Value ComplexExprEmitter::VisitChooseExpr(ChooseExpr *e) {
   return Visit(e->getChosenSubExpr());
 }
 
+mlir::Value
+ComplexExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *e) {
+  mlir::Location loc = cgf.getLoc(e->getExprLoc());
+  QualType complexElemTy =
+      e->getType()->castAs<clang::ComplexType>()->getElementType();
+  mlir::Type complexElemLLVMTy = cgf.convertType(complexElemTy);
+  mlir::TypedAttr defaultValue = builder.getZeroInitAttr(complexElemLLVMTy);
+  auto complexAttr = cir::ConstComplexAttr::get(defaultValue, defaultValue);
+  return builder.create<cir::ConstantOp>(loc, complexAttr);
+}
+
 mlir::Value ComplexExprEmitter::VisitDeclRefExpr(DeclRefExpr *e) {
   if (CIRGenFunction::ConstantEmission constant = cgf.tryEmitAsConstant(e))
     return emitConstant(constant, e);
diff --git a/clang/test/CIR/CodeGen/complex.cpp b/clang/test/CIR/CodeGen/complex.cpp
index 09e0ca03aa540..567fc40df6236 100644
--- a/clang/test/CIR/CodeGen/complex.cpp
+++ b/clang/test/CIR/CodeGen/complex.cpp
@@ -654,3 +654,21 @@ void foo26(int _Complex* a) {
 // OGCG: %[[B_IMAG_PTR:.*]] = getelementptr inbounds nuw { i32, i32 }, ptr %[[COMPLEX_B]], i32 0, i32 1
 // OGCG: store i32 %[[A_REAL]], ptr %[[B_REAL_PTR]], align 4
 // OGCG: store i32 %[[A_IMAG]], ptr %[[B_IMAG_PTR]], align 4
+
+void foo28() {
+  using IntComplex = int _Complex;
+  int _Complex a = IntComplex();
+}
+
+// CIR: %[[INIT:.*]] = cir.alloca !cir.complex<!s32i>, !cir.ptr<!cir.complex<!s32i>>, ["a", init]
+// CIR: %[[COMPLEX:.*]] = cir.const #cir.const_complex<#cir.int<0> : !s32i, #cir.int<0> : !s32i> : !cir.complex<!s32i>
+// CIR: cir.store align(4) %[[COMPLEX]], %[[INIT]] : !cir.complex<!s32i>, !cir.ptr<!cir.complex<!s32i>>
+
+// LLVM: %[[INIT:.*]] = alloca { i32, i32 }, i64 1, align 4
+// LLVM: store { i32, i32 } zeroinitializer, ptr %[[INIT]], align 4
+
+// OGCG: %[[INIT:.*]] = alloca { i32, i32 }, align 4
+// OGCG: %[[INIT_REAL_PTR:.*]] = getelementptr inbounds nuw { i32, i32 }, ptr %[[INIT]], i32 0, i32 0
+// OGCG: %[[INIT_IMAG_PTR:.*]] = getelementptr inbounds nuw { i32, i32 }, ptr %[[INIT]], i32 0, i32 1
+// OGCG: store i32 0, ptr %[[INIT_REAL_PTR]], align 4
+// OGCG: store i32 0, ptr %[[INIT_IMAG_PTR]], align 4

>From d19361b0e27c6e52d5ef055713ded68961f4f4c4 Mon Sep 17 00:00:00 2001
From: AmrDeveloper <amr96 at programmer.net>
Date: Mon, 7 Jul 2025 21:51:44 +0200
Subject: [PATCH 2/2] Replace creating cir::ConstComplexAttr with getNullValue

---
 clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp         |  8 ++------
 clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp | 13 +++++++++++--
 clang/test/CIR/CodeGen/complex.cpp                  |  2 +-
 3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp b/clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp
index 48024b457f848..27c73870e1c4a 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp
@@ -165,12 +165,8 @@ mlir::Value ComplexExprEmitter::VisitChooseExpr(ChooseExpr *e) {
 mlir::Value
 ComplexExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *e) {
   mlir::Location loc = cgf.getLoc(e->getExprLoc());
-  QualType complexElemTy =
-      e->getType()->castAs<clang::ComplexType>()->getElementType();
-  mlir::Type complexElemLLVMTy = cgf.convertType(complexElemTy);
-  mlir::TypedAttr defaultValue = builder.getZeroInitAttr(complexElemLLVMTy);
-  auto complexAttr = cir::ConstComplexAttr::get(defaultValue, defaultValue);
-  return builder.create<cir::ConstantOp>(loc, complexAttr);
+  mlir::Type complexLLVMTy = cgf.convertType(e->getType());
+  return builder.getNullValue(complexLLVMTy, loc);
 }
 
 mlir::Value ComplexExprEmitter::VisitDeclRefExpr(DeclRefExpr *e) {
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 5ac42b6a63b09..09dea282e5718 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -1044,10 +1044,19 @@ mlir::LogicalResult CIRToLLVMConstantOpLowering::matchAndRewrite(
                                                getTypeConverter()));
     return mlir::success();
   } else if (auto complexTy = mlir::dyn_cast<cir::ComplexType>(op.getType())) {
-    auto complexAttr = mlir::cast<cir::ConstComplexAttr>(op.getValue());
-    mlir::Type complexElemTy = complexTy.getElementType();
+    auto complexElemTy = complexTy.getElementType();
     mlir::Type complexElemLLVMTy = typeConverter->convertType(complexElemTy);
 
+    if (auto zeroInitAttr = mlir::dyn_cast<cir::ZeroAttr>(op.getValue())) {
+      mlir::TypedAttr zeroAttr = rewriter.getZeroAttr(complexElemLLVMTy);
+      mlir::ArrayAttr array = rewriter.getArrayAttr({zeroAttr, zeroAttr});
+      rewriter.replaceOpWithNewOp<mlir::LLVM::ConstantOp>(
+          op, getTypeConverter()->convertType(op.getType()), array);
+      return mlir::success();
+    }
+
+    auto complexAttr = mlir::cast<cir::ConstComplexAttr>(op.getValue());
+
     mlir::Attribute components[2];
     if (mlir::isa<cir::IntType>(complexElemTy)) {
       components[0] = rewriter.getIntegerAttr(
diff --git a/clang/test/CIR/CodeGen/complex.cpp b/clang/test/CIR/CodeGen/complex.cpp
index 567fc40df6236..2984a46f3bad8 100644
--- a/clang/test/CIR/CodeGen/complex.cpp
+++ b/clang/test/CIR/CodeGen/complex.cpp
@@ -661,7 +661,7 @@ void foo28() {
 }
 
 // CIR: %[[INIT:.*]] = cir.alloca !cir.complex<!s32i>, !cir.ptr<!cir.complex<!s32i>>, ["a", init]
-// CIR: %[[COMPLEX:.*]] = cir.const #cir.const_complex<#cir.int<0> : !s32i, #cir.int<0> : !s32i> : !cir.complex<!s32i>
+// CIR: %[[COMPLEX:.*]] = cir.const #cir.zero : !cir.complex<!s32i>
 // CIR: cir.store align(4) %[[COMPLEX]], %[[INIT]] : !cir.complex<!s32i>, !cir.ptr<!cir.complex<!s32i>>
 
 // LLVM: %[[INIT:.*]] = alloca { i32, i32 }, i64 1, align 4