[clang] [CIR] Upstream GenericSelectionExpr (PR #146211)

[Amr Hesham via cfe-commits]

https://github.com/AmrDeveloper created https://github.com/llvm/llvm-project/pull/146211

Upstream GenericSelectionExpr for ScalarExpr

>From 351422fe7f124351b06048048dfa28dd03ca35e5 Mon Sep 17 00:00:00 2001
From: AmrDeveloper <amr96 at programmer.net>
Date: Sat, 28 Jun 2025 15:10:36 +0200
Subject: [PATCH] [CIR] Upstream GenericSelectionExpr

---
 clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp |  4 ++++
 clang/test/CIR/CodeGen/generic-selection.c | 24 ++++++++++++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 clang/test/CIR/CodeGen/generic-selection.c

diff --git a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
index 955bb5ffc4395..038df2115f73c 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
@@ -127,6 +127,10 @@ class ScalarExprEmitter : public StmtVisitor<ScalarExprEmitter, mlir::Value> {
 
   mlir::Value VisitParenExpr(ParenExpr *pe) { return Visit(pe->getSubExpr()); }
 
+  mlir::Value VisitGenericSelectionExpr(GenericSelectionExpr *ge) {
+    return Visit(ge->getResultExpr());
+  }
+
   /// Emits the address of the l-value, then loads and returns the result.
   mlir::Value emitLoadOfLValue(const Expr *e) {
     LValue lv = cgf.emitLValue(e);
diff --git a/clang/test/CIR/CodeGen/generic-selection.c b/clang/test/CIR/CodeGen/generic-selection.c
new file mode 100644
index 0000000000000..c1659382a7059
--- /dev/null
+++ b/clang/test/CIR/CodeGen/generic-selection.c
@@ -0,0 +1,24 @@
+// 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=CIR
+// 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
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -Wno-unused-value -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s -check-prefix=OGCG
+
+void foo() {
+  int a;
+  int r = _Generic(a, double: 1, float: 2, int: 3, default: 4);
+}
+
+// CIR: %[[A:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["a"]
+// CIR: %[[RES:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["r", init]
+// CIR: %[[RES_VAL:.*]] = cir.const #cir.int<3> : !s32i
+// CIR: cir.store{{.*}} %[[RES_VAL]], %[[RES]] : !s32i, !cir.ptr<!s32i>
+
+// LLVM: %[[A:.*]] = alloca i32, i64 1, align 4
+// LLVM: %[[RES:.*]] = alloca i32, i64 1, align 4
+// LLVM: store i32 3, ptr %[[RES]], align 4
+
+// OGCG: %[[A:.*]] = alloca i32, align 4
+// OGCG: %[[RES:.*]] = alloca i32, align 4
+// OGCG: store i32 3, ptr %[[RES]], align 4