Don't use native atomics on ivars whose size is not a power of two,

even on architectures that support unaligned access (which is the
only way this is otherwise legal, given that ivars apparently do
not honor alignment attributes).

llvm-svn: 139590

1 files changed, 29 insertions, 0 deletions

diff --git a/clang/test/CodeGenObjC/property-aggregate.m b/clang/test/CodeGenObjC/property-aggregate.m
new file mode 100644
index 00000000000..f4b4dc96151
--- /dev/null
+++ b/clang/test/CodeGenObjC/property-aggregate.m
@@ -0,0 +1,29 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -fobjc-nonfragile-abi -emit-llvm %s -o - | FileCheck %s
+
+// This structure's size is not a power of two, so the property does
+// not get native atomics, even though x86-64 can do unaligned atomics
+// with a lock prefix.
+struct s3 { char c[3]; };
+
+// This structure's size is, so it does, because it can.
+struct s4 { char c[4]; };
+
+@interface Test0
+@property struct s3 s3;
+@property struct s4 s4;
+@end
+@implementation Test0
+@synthesize s3, s4;
+@end
+
+// CHECK: define internal i24 @"\01-[Test0 s3]"(
+// CHECK: call void @objc_copyStruct
+
+// CHECK: define internal void @"\01-[Test0 setS3:]"(
+// CHECK: call void @objc_copyStruct
+
+// CHECK: define internal i32 @"\01-[Test0 s4]"(
+// CHECK: load atomic i32* {{%.*}} unordered, align 1
+
+// CHECK: define internal void @"\01-[Test0 setS4:]"(
+// CHECK: store atomic i32 {{%.*}}, i32* {{%.*}} unordered, align 1