[clang] [CIR] Implement ChooseExpr for Aggre Expr (PR #160999)

[Amr Hesham via cfe-commits]

https://github.com/AmrDeveloper created https://github.com/llvm/llvm-project/pull/160999

Implement the ChooseExpr for aggregate expr

>From ca7a482c87d003d5169abc188774e13a600ec018 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E2=80=9CAmr?= <amr96 at programmer.net>
Date: Sat, 27 Sep 2025 12:21:52 +0200
Subject: [PATCH] [CIR] Implement ChooseExpr for Aggre Expr

---
 clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp |  4 +---
 clang/lib/CIR/CodeGen/CIRGenFunction.cpp      |  2 ++
 clang/test/CIR/CodeGen/struct.cpp             | 24 +++++++++++++++++++
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp b/clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp
index 4a8aac900ee07..297fbccc6336e 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp
@@ -213,9 +213,7 @@ class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
     cgf.cgm.errorNYI(e->getSourceRange(),
                      "AggExprEmitter: VisitAbstractConditionalOperator");
   }
-  void VisitChooseExpr(const ChooseExpr *e) {
-    cgf.cgm.errorNYI(e->getSourceRange(), "AggExprEmitter: VisitChooseExpr");
-  }
+  void VisitChooseExpr(const ChooseExpr *e) { Visit(e->getChosenSubExpr()); }
   void VisitCXXParenListInitExpr(CXXParenListInitExpr *e) {
     cgf.cgm.errorNYI(e->getSourceRange(),
                      "AggExprEmitter: VisitCXXParenListInitExpr");
diff --git a/clang/lib/CIR/CodeGen/CIRGenFunction.cpp b/clang/lib/CIR/CodeGen/CIRGenFunction.cpp
index 0abb21a670719..9d98361a8b6a2 100644
--- a/clang/lib/CIR/CodeGen/CIRGenFunction.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenFunction.cpp
@@ -841,6 +841,8 @@ LValue CIRGenFunction::emitLValue(const Expr *e) {
     return emitCastLValue(cast<CastExpr>(e));
   case Expr::MaterializeTemporaryExprClass:
     return emitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(e));
+  case Expr::ChooseExprClass:
+    return emitLValue(cast<ChooseExpr>(e)->getChosenSubExpr());
   }
 }
 
diff --git a/clang/test/CIR/CodeGen/struct.cpp b/clang/test/CIR/CodeGen/struct.cpp
index ee6c4cab7341f..0a0290e16a008 100644
--- a/clang/test/CIR/CodeGen/struct.cpp
+++ b/clang/test/CIR/CodeGen/struct.cpp
@@ -93,3 +93,27 @@ void f3() {
 // OGCG:   %[[O:.*]] = alloca %struct.Outer, align 4
 // OGCG:   %[[O_I:.*]] = getelementptr inbounds nuw %struct.Outer, ptr %[[O]], i32 0, i32 0
 // OGCG:   %[[O_I_N:.*]] = getelementptr inbounds nuw %struct.Inner, ptr %[[O_I]], i32 0, i32 0
+
+void choose_expr() {
+  CompleteS a;
+  CompleteS b;
+  CompleteS c = __builtin_choose_expr(true, a, b);
+}
+
+// CIR: cir.func{{.*}} @_Z11choose_exprv()
+// CIR:   %[[A_ADDR:.*]] = cir.alloca !rec_CompleteS, !cir.ptr<!rec_CompleteS>, ["a"]
+// CIR:   %[[B_ADDR:.*]] = cir.alloca !rec_CompleteS, !cir.ptr<!rec_CompleteS>, ["b"]
+// CIR:   %[[C_ADDR:.*]] = cir.alloca !rec_CompleteS, !cir.ptr<!rec_CompleteS>, ["c", init]
+// CIR:   cir.call @_ZN9CompleteSC1ERKS_(%[[C_ADDR]], %[[A_ADDR]]) nothrow : (!cir.ptr<!rec_CompleteS>, !cir.ptr<!rec_CompleteS>) -> ()
+
+// LLVM: define{{.*}} void @_Z11choose_exprv()
+// LLVM:   %[[A_ADDR:.*]] = alloca %struct.CompleteS, i64 1, align 4
+// LLVM:   %[[B_ADDR:.*]] = alloca %struct.CompleteS, i64 1, align 4
+// LLVM:   %[[C_ADDR:.*]] = alloca %struct.CompleteS, i64 1, align 4
+// LLVM:   call void @_ZN9CompleteSC1ERKS_(ptr %[[C_ADDR]], ptr %[[A_ADDR]])
+
+// OGCG: define{{.*}} void @_Z11choose_exprv()
+// OGCG:   %[[A_ADDR:.*]] = alloca %struct.CompleteS, align 4
+// OGCG:   %[[B_ADDR:.*]] = alloca %struct.CompleteS, align 4
+// OGCG:   %[[C_ADDR:.*]] = alloca %struct.CompleteS, align 4
+// OGCG:   call void @llvm.memcpy.p0.p0.i64(ptr align 4 %[[C_ADDR]], ptr align 4 %[[A_ADDR]], i64 8, i1 false)