[clang] [CIR][CodeGen] Implement VisitImplicitValueInitExpr in CIRGenExprScalar.cpp (PR #182256)

[Gauravsingh Sisodia via cfe-commits]

https://github.com/xaerru updated https://github.com/llvm/llvm-project/pull/182256

>From 782bdc8c87946c15eea9b819343e9574c848a6da Mon Sep 17 00:00:00 2001
From: Gauravsingh Sisodia <xaerru at gmail.com>
Date: Thu, 19 Feb 2026 12:14:11 +0000
Subject: [PATCH 1/2] [CIR][CodeGen] Implement VisitImplicitValueInitExpr in
 CIRGenExprScalar.cpp

---
 clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
index 2c5a57e1ba2ee..3d51a5c7e1979 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
@@ -420,9 +420,7 @@ class ScalarExprEmitter : public StmtVisitor<ScalarExprEmitter, mlir::Value> {
   }
 
   mlir::Value VisitImplicitValueInitExpr(const ImplicitValueInitExpr *e) {
-    cgf.cgm.errorNYI(e->getSourceRange(),
-                     "ScalarExprEmitter: implicit value init");
-    return {};
+    return emitNullValue(e->getType(), cgf.getLoc(e->getSourceRange()));
   }
 
   mlir::Value VisitExplicitCastExpr(ExplicitCastExpr *e) {

>From 1dbc21f0acaf615290f3b3eab52c28e134dd8931 Mon Sep 17 00:00:00 2001
From: Gauravsingh Sisodia <xaerru at gmail.com>
Date: Tue, 24 Feb 2026 17:34:20 +0000
Subject: [PATCH 2/2] [CIR][CodeGen] Add test for VisitImplicitValueInitExpr

---
 .../CIR/CodeGen/implicit-value-init-expr.cpp  | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 clang/test/CIR/CodeGen/implicit-value-init-expr.cpp

diff --git a/clang/test/CIR/CodeGen/implicit-value-init-expr.cpp b/clang/test/CIR/CodeGen/implicit-value-init-expr.cpp
new file mode 100644
index 0000000000000..ad9f430411fba
--- /dev/null
+++ b/clang/test/CIR/CodeGen/implicit-value-init-expr.cpp
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -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 -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 -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s -check-prefix=OGCG
+
+void* operator new(__SIZE_TYPE__, void* p) noexcept { return p; }
+
+void test(void *p) {
+  new (p) int();
+}
+
+// CIR:     cir.func{{.*}} @_Z4testPv
+// CIR-NEXT:    %[[P:.*]] = cir.alloca !cir.ptr<!void>, !cir.ptr<!cir.ptr<!void>>, ["p", init] {alignment = 8 : i64}
+// CIR-NEXT:    cir.store %arg0, %[[P]] : !cir.ptr<!void>, !cir.ptr<!cir.ptr<!void>>
+// CIR-NEXT:    %[[P1:.*]] = cir.load align(8) %[[P]] : !cir.ptr<!cir.ptr<!void>>, !cir.ptr<!void>
+// CIR-NEXT:    %[[P2:.*]] = cir.cast bitcast %[[P1]] : !cir.ptr<!void> -> !cir.ptr<!s32i>
+// CIR-NEXT:    %[[P3:.*]] = cir.const #cir.int<0> : !s32i
+// CIR-NEXT:    cir.store align(4) %[[P3]], %[[P2]] : !s32i, !cir.ptr<!s32i>
+
+// LLVM:    define{{.*}} void @_Z4testPv(ptr{{.*}} %[[ARG:.*]])
+// LLVM-NEXT:   %[[P:.*]] = alloca ptr, i64 1, align 8
+// LLVM-NEXT:   store ptr %[[ARG]], ptr %[[P]], align 8
+// LLVM-NEXT:   %[[P1:.*]] = load ptr, ptr %[[P]], align 8
+// LLVM-NEXT:   store i32 0, ptr %[[P1]], align 4
+// LLVM-NEXT:   ret void
+
+// OGCG:    define{{.*}} void @_Z4testPv(ptr{{.*}} %[[ARG:.*]])
+// OGCG-NEXT:   {{.*}}:
+// OGCG-NEXT:   %[[P:.*]] = alloca ptr, align 8
+// OGCG-NEXT:   store ptr %[[ARG]], ptr %[[P]], align 8
+// OGCG-NEXT:   %[[P1:.*]] = load ptr, ptr %[[P]], align 8
+// OGCG-NEXT:   store i32 0, ptr %[[P1]], align 4
+// OGCG-NEXT:   ret void