[clang] [CIR] Upstream CXXParenListInitExpr for AggregateExpr (PR #161876)

[Amr Hesham via cfe-commits]

https://github.com/AmrDeveloper created https://github.com/llvm/llvm-project/pull/161876

Upstream the CXXParenListInitExpr support for AggregateExpr

>From ea59456b47fe0f64a8ab7b2d2211667ca10e5fe0 Mon Sep 17 00:00:00 2001
From: Amr Hesham <amr96 at programmer.net>
Date: Fri, 3 Oct 2025 18:19:19 +0200
Subject: [PATCH] [CIR] Upstream CXXParenListInitExpr for AggregateExpr

---
 clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp |  6 ++--
 clang/test/CIR/CodeGen/paren-init-list.cpp    | 30 +++++++++++++++++++
 2 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100644 clang/test/CIR/CodeGen/paren-init-list.cpp

diff --git a/clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp b/clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp
index 1e987f3bedc7e..ba60ba4657800 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp
@@ -212,9 +212,11 @@ class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
   }
   void VisitChooseExpr(const ChooseExpr *e) { Visit(e->getChosenSubExpr()); }
   void VisitCXXParenListInitExpr(CXXParenListInitExpr *e) {
-    cgf.cgm.errorNYI(e->getSourceRange(),
-                     "AggExprEmitter: VisitCXXParenListInitExpr");
+    visitCXXParenListOrInitListExpr(e, e->getInitExprs(),
+                                    e->getInitializedFieldInUnion(),
+                                    e->getArrayFiller());
   }
+
   void VisitArrayInitLoopExpr(const ArrayInitLoopExpr *e,
                               llvm::Value *outerBegin = nullptr) {
     cgf.cgm.errorNYI(e->getSourceRange(),
diff --git a/clang/test/CIR/CodeGen/paren-init-list.cpp b/clang/test/CIR/CodeGen/paren-init-list.cpp
new file mode 100644
index 0000000000000..0efa36352899e
--- /dev/null
+++ b/clang/test/CIR/CodeGen/paren-init-list.cpp
@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --check-prefix=LLVM --input-file=%t-cir.ll %s
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o %t.ll
+// RUN: FileCheck --check-prefix=OGCG --input-file=%t.ll %s
+
+struct CompleteS {
+  int a;
+  char b;
+};
+
+void cxx_paren_list_init_expr() { CompleteS a(1, 'a'); }
+
+// CIR: %[[A_ADDR:.*]] = cir.alloca !rec_CompleteS, !cir.ptr<!rec_CompleteS>, ["a", init]
+// CIR: %[[ELEM_0_PTR:.*]] = cir.get_member %[[A_ADDR]][0] {name = "a"} : !cir.ptr<!rec_CompleteS> -> !cir.ptr<!s32i>
+// CIR: %[[ELEM_0_VAL:.*]] = cir.const #cir.int<1> : !s32i
+// CIR: cir.store{{.*}} %[[ELEM_0_VAL]], %[[ELEM_0_PTR]] : !s32i, !cir.ptr<!s32i>
+// CIR: %[[ELEM_1_PTR:.*]] = cir.get_member %[[A_ADDR]][1] {name = "b"} : !cir.ptr<!rec_CompleteS> -> !cir.ptr<!s8i>
+// CIR: %[[ELEM_1_VAL:.*]] = cir.const #cir.int<97> : !s8i
+// CIR: cir.store{{.*}} %[[ELEM_1_VAL]], %[[ELEM_1_PTR]] : !s8i, !cir.ptr<!s8i>
+
+// LLVM: %[[A_ADDR:.*]] = alloca %struct.CompleteS, i64 1, align 4
+// LLVM: %[[ELEM_0_PTR:.*]] = getelementptr %struct.CompleteS, ptr %[[A_ADDR]], i32 0, i32 0
+// LLVM: store i32 1, ptr %[[ELEM_0_PTR]], align 4
+// LLVM: %[[ELEM_1_PTR:.*]] = getelementptr %struct.CompleteS, ptr %[[A_ADDR]], i32 0, i32 1
+// LLVM: store i8 97, ptr %[[ELEM_1_PTR]], align 4
+
+// OGCG: %[[A_ADDR:.*]] = alloca %struct.CompleteS, align 4
+// OGCG: call void @llvm.memcpy.p0.p0.i64(ptr align 4 %[[A_ADDR]], ptr align 4 @__const._Z24cxx_paren_list_init_exprv.a, i64 8, i1 false)