[clang] [CodeGen] Fix handling of nullptr in initializers (PR #137364)

[Alexander Kornienko via cfe-commits]

https://github.com/alexfh created https://github.com/llvm/llvm-project/pull/137364

Fixes https://github.com/llvm/llvm-project/issues/137276.


>From 5431de1664814a7a2dcc93695eed8745ae6bfef5 Mon Sep 17 00:00:00 2001
From: Alexander Kornienko <alexfh at google.com>
Date: Fri, 25 Apr 2025 17:51:03 +0200
Subject: [PATCH] [CodeGen] Fix handling of nullptr in initializers

Fixes https://github.com/llvm/llvm-project/issues/137276.
---
 clang/lib/CodeGen/CodeGenTypes.cpp |  6 ++++--
 clang/test/CodeGenCXX/pr137276.cpp | 13 +++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)
 create mode 100644 clang/test/CodeGenCXX/pr137276.cpp

diff --git a/clang/lib/CodeGen/CodeGenTypes.cpp b/clang/lib/CodeGen/CodeGenTypes.cpp
index b94c11802a268..d1b292f23c2d2 100644
--- a/clang/lib/CodeGen/CodeGenTypes.cpp
+++ b/clang/lib/CodeGen/CodeGenTypes.cpp
@@ -850,12 +850,14 @@ CodeGenTypes::getCGRecordLayout(const RecordDecl *RD) {
 }
 
 bool CodeGenTypes::isPointerZeroInitializable(QualType T) {
-  assert((T->isAnyPointerType() || T->isBlockPointerType()) && "Invalid type");
+  assert((T->isAnyPointerType() || T->isBlockPointerType() ||
+          T->isNullPtrType()) &&
+         "Invalid type");
   return isZeroInitializable(T);
 }
 
 bool CodeGenTypes::isZeroInitializable(QualType T) {
-  if (T->getAs<PointerType>())
+  if (T->getAs<PointerType>() || T->isNullPtrType())
     return Context.getTargetNullPointerValue(T) == 0;
 
   if (const auto *AT = Context.getAsArrayType(T)) {
diff --git a/clang/test/CodeGenCXX/pr137276.cpp b/clang/test/CodeGenCXX/pr137276.cpp
new file mode 100644
index 0000000000000..0664a121ad6a0
--- /dev/null
+++ b/clang/test/CodeGenCXX/pr137276.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-linux-gnu -emit-llvm -o - %s | FileCheck %s
+
+using ulong = unsigned long;
+template <class... Ts>
+void g(Ts... args) {
+  ulong arr[3] = {ulong(args)...};
+  (void)arr;
+}
+extern void f() {
+  g(nullptr, 17);
+}
+
+// CHECK: {{^}}  store i64 0, ptr %arr, align 8{{$}}