diff --git a/test/CodeGen/X86/rdtsc.ll b/test/CodeGen/X86/rdtsc.ll
new file mode 100644
index 00000000000..289224ea268
--- /dev/null
+++ b/test/CodeGen/X86/rdtsc.ll
@@ -0,0 +1,10 @@
+; RUN: llvm-as < %s | llc -march=x86 | grep rptsc
+
+declare ulong %llvm.readcyclecounter()
+
+void %foo() {
+entry:
+%tmp.1 = call ulong %llvm.readcyclecounter ()
+ret void
+}
+