Fix undefined use of memcpy and memcmp

Don't call them on a nullptr, even with a length of 0.

Change-Id: I7fee23303562e5771697a16365cae12e3e87af6f
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h
index eacc373ee3..2b1b155efb 100644
--- a/src/corelib/tools/qhash.h
+++ b/src/corelib/tools/qhash.h
@@ -397,7 +397,8 @@ struct Span {
         // we only add storage if the previous storage was fully filled, so
         // simply copy the old data over
         if constexpr (isRelocatable<Node>()) {
-            memcpy(newEntries, entries, allocated*sizeof(Entry));
+            if (allocated)
+                memcpy(newEntries, entries, allocated*sizeof(Entry));
         } else {
             for (size_t i = 0; i < allocated; ++i) {
                 new (&newEntries[i].node()) Node(std::move(entries[i].node()));