1 files changed, 41 insertions, 0 deletions
diff --git a/test/CodeGenCXX/std-byte.cpp b/test/CodeGenCXX/std-byte.cpp
new file mode 100644
index 0000000000000..a3cc634221bf0
--- /dev/null
+++ b/test/CodeGenCXX/std-byte.cpp
@@ -0,0 +1,41 @@
+// RUN: %clang_cc1 -std=c++1z -Werror -triple i386-unknown-unknown -emit-llvm -O1 -disable-llvm-passes -o - %s | FileCheck %s
+
+// std::byte should be considered equivalent to char for aliasing.
+
+namespace std {
+enum byte : unsigned char {};
+}
+
+// CHECK-LABEL: define void @test0(
+extern "C" void test0(std::byte *sb, int *i) {
+  // CHECK: store i8 0, i8* %{{.*}} !tbaa [[TAG_CHAR:!.*]]
+  *sb = std::byte{0};
+
+  // CHECK: store i32 1, i32* %{{.*}} !tbaa [[TAG_INT:!.*]]
+  *i = 1;
+}
+
+enum byte : unsigned char {};
+namespace my {
+enum byte : unsigned char {};
+namespace std {
+enum byte : unsigned char {};
+} // namespace std
+} // namespace my
+
+// Make sure we don't get confused with other enums named 'byte'.
+
+// CHECK-LABEL: define void @test1(
+extern "C" void test1(::byte *b, ::my::byte *mb, ::my::std::byte *msb) {
+  *b = ::byte{0};
+  *mb = ::my::byte{0};
+  *msb = ::my::std::byte{0};
+  // CHECK-NOT: store i8 0, i8* %{{.*}} !tbaa [[TAG_CHAR]]
+}
+
+// CHECK:  !"any pointer", [[TYPE_CHAR:!.*]],
+// CHECK: [[TYPE_CHAR]] = !{!"omnipotent char", [[TAG_CXX_TBAA:!.*]],
+// CHECK: [[TAG_CXX_TBAA]] = !{!"Simple C++ TBAA"}
+// CHECK: [[TAG_CHAR]] = !{[[TYPE_CHAR:!.*]], [[TYPE_CHAR]], i64 0}
+// CHECK: [[TAG_INT]] = !{[[TYPE_INT:!.*]], [[TYPE_INT]], i64 0}
+// CHECK: [[TYPE_INT]] = !{!"int", [[TYPE_CHAR]]