[lldb] [lit/Register] XFAIL on Darwin

llvm-svn: 358224
diff --git a/lldb/lit/Register/x86-mm-xmm-read.test b/lldb/lit/Register/x86-mm-xmm-read.test
index f806c03..510d131 100644
--- a/lldb/lit/Register/x86-mm-xmm-read.test
+++ b/lldb/lit/Register/x86-mm-xmm-read.test
@@ -1,3 +1,4 @@
+# XFAIL: system-darwin
 # XFAIL: system-windows
 # REQUIRES: native && (target-x86 || target-x86_64)
 # RUN: %clangxx %p/Inputs/x86-mm-xmm-read.cpp -o %t