[TSan] use efficient real_memcpy inside runtime

llvm-svn: 158260
diff --git a/compiler-rt/lib/tsan/rtl/tsan_sync.cc b/compiler-rt/lib/tsan/rtl/tsan_sync.cc
index e917c5b..36b316a 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_sync.cc
+++ b/compiler-rt/lib/tsan/rtl/tsan_sync.cc
@@ -155,7 +155,7 @@
     return;
   n_ = cnt;
   s_ = (uptr*)internal_alloc(MBlockStackTrace, cnt * sizeof(s_[0]));
-  internal_memcpy(s_, pcs, cnt * sizeof(s_[0]));
+  real_memcpy(s_, pcs, cnt * sizeof(s_[0]));
 }
 
 void StackTrace::ObtainCurrent(ThreadState *thr, uptr toppc) {