Implement CodeGen support for the may_alias attribute.

llvm-svn: 121734

1 files changed, 21 insertions, 0 deletions

diff --git a/clang/test/CodeGen/may-alias.c b/clang/test/CodeGen/may-alias.c
new file mode 100644
index 00000000000..66744b7ccea
--- /dev/null
+++ b/clang/test/CodeGen/may-alias.c
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -Werror -triple i386-unknown-unknown -emit-llvm -O1 -disable-llvm-optzns -o %t %s
+// RUN: FileCheck < %t %s
+
+// Types with the may_alias attribute should be considered equivalent
+// to char for aliasing.
+
+typedef int __attribute__((may_alias)) aliasing_int;
+
+void test0(aliasing_int *ai, int *i)
+{
+  *ai = 0;
+  *i = 1;
+}
+
+// CHECK: store i32 0, i32* %tmp, !tbaa !1
+// CHECK: store i32 1, i32* %tmp1, !tbaa !3
+
+// CHECK: !0 = metadata !{metadata !"any pointer", metadata !1}
+// CHECK: !1 = metadata !{metadata !"omnipotent char", metadata !2}
+// CHECK: !2 = metadata !{metadata !"Simple C/C++ TBAA", null}
+// CHECK: !3 = metadata !{metadata !"int", metadata !1}