fix flaky ConnectTFOTimeout and ConnectTFOFallbackTimeout tests

[folly.git] / folly / FBVector.h

diff --git a/folly/FBVector.h b/folly/FBVector.h
index e1809f3179370ed5455c7ef93d6d1f5b5547a199..036882a4930414a1c8def4cafae5785c66454720 100644 (file)
--- a/folly/FBVector.h
+++ b/folly/FBVector.h
@@ -522,7 +522,9 @@ private:
 
   static void
   S_uninitialized_copy_bits(T* dest, const T* first, const T* last) {
-    std::memcpy((void*)dest, (void*)first, (last - first) * sizeof(T));
+    if (last != first) {
+      std::memcpy((void*)dest, (void*)first, (last - first) * sizeof(T));
+    }
   }
 
   static void
@@ -530,7 +532,9 @@ private:
                        std::move_iterator<T*> last) {
     T* bFirst = first.base();
     T* bLast = last.base();
-    std::memcpy((void*)dest, (void*)bFirst, (bLast - bFirst) * sizeof(T));
+    if (bLast != bFirst) {
+      std::memcpy((void*)dest, (void*)bFirst, (bLast - bFirst) * sizeof(T));
+    }
   }
 
   template <typename It>
@@ -636,7 +640,9 @@ private:
   }
 
   void relocate_move_or_memcpy(T* dest, T* first, T* last, std::true_type) {
-    std::memcpy((void*)dest, (void*)first, (last - first) * sizeof(T));
+    if (first != nullptr) {
+      std::memcpy((void*)dest, (void*)first, (last - first) * sizeof(T));
+    }
   }
 
   void relocate_move_or_memcpy(T* dest, T* first, T* last, std::false_type) {