merge of 5.1-bugteam

3 files changed, 9 insertions, 8 deletions

diff --git a/sql/field_conv.cc b/sql/field_conv.cc
index ea6ff82e0aa..20c647ccc00 100644
--- a/sql/field_conv.cc
+++ b/sql/field_conv.cc
@@ -787,11 +787,8 @@ int field_conv(Field *to,Field *from)
          ((Field_varstring*)from)->length_bytes ==
           ((Field_varstring*)to)->length_bytes))
     {						// Identical fields
-#ifdef HAVE_purify
-      /* This may happen if one does 'UPDATE ... SET x=x' */
-      if (to->ptr != from->ptr)
-#endif
-        memcpy(to->ptr,from->ptr,to->pack_length());
+      // to->ptr==from->ptr may happen if one does 'UPDATE ... SET x=x'
+      memmove(to->ptr, from->ptr, to->pack_length());
       return 0;
     }
   }
diff --git a/sql/item_func.cc b/sql/item_func.cc
index bef0e461a1f..4551962a2c1 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -4331,7 +4331,7 @@ update_hash(user_var_entry *entry, bool set_null, void *ptr, uint length,
       length--;					// Fix length change above
       entry->value[length]= 0;			// Store end \0
     }
-    memcpy(entry->value,ptr,length);
+    memmove(entry->value, ptr, length);
     if (type == DECIMAL_RESULT)
       ((my_decimal*)entry->value)->fix_buffer_pointer();
     entry->length= length;
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index e9373bc455f..066b279cba0 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -4050,8 +4050,12 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
 	  continue;
       }
 
-#ifdef HAVE_purify
-      /* Valgrind complains about overlapped memcpy when save_pos==use. */
+#if defined(__GNUC__) && !MY_GNUC_PREREQ(4,4)
+      /*
+        Old gcc used a memcpy(), which is undefined if save_pos==use:
+        http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19410
+        http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39480
+      */
       if (save_pos != use)
 #endif
         *save_pos= *use;