From 21b6d4fa519aa1505c8e102071d06830ac4d7ff4 Mon Sep 17 00:00:00 2001
From: Chuanqi Xu <yedeng.yd@linux.alibaba.com>
Date: Tue, 15 Oct 2024 14:50:53 +0800
Subject: [PATCH] [CIR] [Lowering] care trailing zero for lowering constant
 array

---
 clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp | 5 ++++-
 clang/test/CIR/Lowering/str.c                       | 9 +++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 clang/test/CIR/Lowering/str.c

diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 94d889d535d0..93221b409df2 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -2229,7 +2229,10 @@ class CIRGlobalOpLowering
     if (auto constArr =
             mlir::dyn_cast<mlir::cir::ConstArrayAttr>(init.value())) {
       if (auto attr = mlir::dyn_cast<mlir::StringAttr>(constArr.getElts())) {
-        init = rewriter.getStringAttr(attr.getValue());
+        llvm::SmallString<256> literal(attr.getValue());
+        if (constArr.getTrailingZerosNum())
+          literal.append(constArr.getTrailingZerosNum(), '\0');
+        init = rewriter.getStringAttr(literal);
       } else if (auto attr =
                      mlir::dyn_cast<mlir::ArrayAttr>(constArr.getElts())) {
         // Failed to use a compact attribute as an initializer:
diff --git a/clang/test/CIR/Lowering/str.c b/clang/test/CIR/Lowering/str.c
new file mode 100644
index 000000000000..cc393daee884
--- /dev/null
+++ b/clang/test/CIR/Lowering/str.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s -check-prefix=LLVM
+
+void f(char *fmt, ...);
+void test() {
+    f("test\0");
+}
+
+// LLVM: @.str = {{.*}}[6 x i8] c"test\00\00"