1 files changed, 42 insertions, 0 deletions
diff --git a/test/tsan/memcmp_race.cc b/test/tsan/memcmp_race.cc
new file mode 100644
index 000000000000..b76f427e121c
--- /dev/null
+++ b/test/tsan/memcmp_race.cc
@@ -0,0 +1,42 @@
+// RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
+#include "test.h"
+#include <string.h>
+
+char *data0 = new char[10];
+char *data1 = new char[10];
+char *data2 = new char[10];
+
+void *Thread1(void *x) {
+  static volatile int size = 1;
+  static volatile int sink;
+  sink = memcmp(data0+5, data1, size);
+  barrier_wait(&barrier);
+  return NULL;
+}
+
+void *Thread2(void *x) {
+  static volatile int size = 4;
+  barrier_wait(&barrier);
+  memcpy(data0+5, data2, size);
+  return NULL;
+}
+
+int main() {
+  barrier_init(&barrier, 2);
+  print_address("addr=", 1, &data0[5]);
+  pthread_t t[2];
+  pthread_create(&t[0], NULL, Thread1, NULL);
+  pthread_create(&t[1], NULL, Thread2, NULL);
+  pthread_join(t[0], NULL);
+  pthread_join(t[1], NULL);
+  return 0;
+}
+
+// CHECK: addr=[[ADDR:0x[0-9,a-f]+]]
+// CHECK: WARNING: ThreadSanitizer: data race
+// CHECK:   Write of size 1 at [[ADDR]] by thread T2:
+// CHECK:     #0 {{(memcpy|memmove)}}
+// CHECK:     #1 Thread2
+// CHECK:   Previous read of size 1 at [[ADDR]] by thread T1:
+// CHECK:     #0 memcmp
+// CHECK:     #1 Thread1