[clang] [CIR] Implement DesignatedInitUpdateExpr for AggregateExpr (PR #161897)

[Amr Hesham via cfe-commits]

https://github.com/AmrDeveloper updated https://github.com/llvm/llvm-project/pull/161897

>From f26cf54f2d9101c7c59619eed20e1ba725ffee4a Mon Sep 17 00:00:00 2001
From: Amr Hesham <amr96 at programmer.net>
Date: Fri, 3 Oct 2025 21:36:31 +0200
Subject: [PATCH] [CIR] Implement DesignatedInitUpdateExpr for AggregateExpr

---
 clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp |  6 ++--
 clang/test/CIR/CodeGen/struct.cpp             | 33 +++++++++++++++++++
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp b/clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp
index 1e987f3bedc7e..29cb709d03beb 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp
@@ -203,8 +203,10 @@ class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
   }
 
   void VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *e) {
-    cgf.cgm.errorNYI(e->getSourceRange(),
-                     "AggExprEmitter: VisitDesignatedInitUpdateExpr");
+    AggValueSlot dest = ensureSlot(cgf.getLoc(e->getExprLoc()), e->getType());
+    LValue destLV = cgf.makeAddrLValue(dest.getAddress(), e->getType());
+    emitInitializationToLValue(e->getBase(), destLV);
+    VisitInitListExpr(e->getUpdater());
   }
   void VisitAbstractConditionalOperator(const AbstractConditionalOperator *e) {
     cgf.cgm.errorNYI(e->getSourceRange(),
diff --git a/clang/test/CIR/CodeGen/struct.cpp b/clang/test/CIR/CodeGen/struct.cpp
index 96db82a89977c..d95901fa66c0e 100644
--- a/clang/test/CIR/CodeGen/struct.cpp
+++ b/clang/test/CIR/CodeGen/struct.cpp
@@ -183,3 +183,36 @@ void generic_selection() {
 // OGCG:   %[[C_ADDR:.*]] = alloca i32, align 4
 // OGCG:   %[[D_ADDR:.*]] = alloca %struct.CompleteS, align 4
 // OGCG:   call void @llvm.memcpy.p0.p0.i64(ptr align 4 %[[D_ADDR]], ptr align 4 %[[A_ADDR]], i64 8, i1 false)
+
+void designated_init_update_expr() {
+  CompleteS a;
+
+  struct Container {
+    CompleteS c;
+  } b = {a, .c.a = 1};
+}
+
+// CIR: %[[A_ADDR:.*]] = cir.alloca !rec_CompleteS, !cir.ptr<!rec_CompleteS>, ["a"]
+// CIR: %[[B_ADDR:.*]] = cir.alloca !rec_Container, !cir.ptr<!rec_Container>, ["b", init]
+// CIR: %[[C_ADDR:.*]] = cir.get_member %[[B_ADDR]][0] {name = "c"} : !cir.ptr<!rec_Container> -> !cir.ptr<!rec_CompleteS>
+// CIR: cir.call @_ZN9CompleteSC1ERKS_(%2, %[[A_ADDR]]) nothrow : (!cir.ptr<!rec_CompleteS>, !cir.ptr<!rec_CompleteS>) -> ()
+// CIR: %[[ELEM_0_PTR:.*]] = cir.get_member %[[C_ADDR]][0] {name = "a"} : !cir.ptr<!rec_CompleteS> -> !cir.ptr<!s32i>
+// CIR: %[[CONST_1:.*]] = cir.const #cir.int<1> : !s32i
+// CIR: cir.store{{.*}} %[[CONST_1]], %[[ELEM_0_PTR]] : !s32i, !cir.ptr<!s32i>
+// CIR: %[[ELEM_1_PTR:.*]] = cir.get_member %[[C_ADDR]][1] {name = "b"} : !cir.ptr<!rec_CompleteS> -> !cir.ptr<!s8i>
+
+// LLVM: %[[A_ADDR:.*]] = alloca %struct.CompleteS, i64 1, align 4
+// LLVM: %[[B_ADDR:.*]] = alloca %struct.Container, i64 1, align 4
+// LLVM: %[[C_ADDR:.*]] = getelementptr %struct.Container, ptr %[[B_ADDR]], i32 0, i32 0
+// LLVM: call void @_ZN9CompleteSC1ERKS_(ptr %[[C_ADDR]], ptr %[[A_ADDR]])
+// LLVM: %[[ELEM_0_PTR:.*]] = getelementptr %struct.CompleteS, ptr %[[C_ADDR]], i32 0, i32 0
+// LLVM: store i32 1, ptr %[[ELEM_0_PTR]], align 4
+// LLVM: %[[ELEM_1_PTR:.*]] = getelementptr %struct.CompleteS, ptr %[[C_ADDR]], i32 0, i32 1
+
+// OGCG: %[[A_ADDR:.*]] = alloca %struct.CompleteS, align 4
+// OGCG: %[[B_ADDR:.*]] = alloca %struct.Container, align 4
+// OGCG: %[[C_ADDR:.*]] = getelementptr inbounds nuw %struct.Container, ptr %[[B_ADDR]], i32 0, i32 0
+// OGCG: call void @llvm.memcpy.p0.p0.i64(ptr align 4 %[[C_ADDR]], ptr align 4 %[[A_ADDR]], i64 8, i1 false)
+// OGCG: %[[ELEM_0_PTR:.*]] = getelementptr inbounds nuw %struct.CompleteS, ptr %[[C_ADDR]], i32 0, i32 0
+// OGCG: store i32 1, ptr %[[ELEM_0_PTR]], align 4
+// OGCG: %[[ELEM_1_PTR:.*]] = getelementptr inbounds nuw %struct.CompleteS, ptr %[[C_ADDR]], i32 0, i32 1