Index: source/Utility/FileSpec.cpp
===================================================================
--- source/Utility/FileSpec.cpp
+++ source/Utility/FileSpec.cpp
@@ -404,8 +404,30 @@
   // case sensitivity of equality test
   const bool case_sensitive = a.IsCaseSensitive() || b.IsCaseSensitive();
 
+  // First test for filename inequality since that is cheap.
+  // The only case where the filenames might be unequal but GetNormalizedPath
+  // will resolve to equal paths is if the filename component of one or 
+  // the other FileSpec's is "." or "..", and then only if remove_backups
+  // is true.
+  
+  static ConstString g_dot_string(".");
+  static ConstString g_dot_dot_string("..");
+  
+  bool filenames_equal = ConstString::Equals(a.m_filename, 
+                                             b.m_filename, 
+                                             case_sensitive);
+  bool last_component_is_dot = ConstString::Equals(a.m_filename, g_dot_string) 
+                               || ConstString::Equals(a.m_filename, 
+                                                      g_dot_dot_string)
+                               || ConstString::Equals(b.m_filename, 
+                                                      g_dot_string)
+                               || ConstString::Equals(b.m_filename, 
+                                                      g_dot_dot_string);
+  if (!filenames_equal && !(remove_backups || last_component_is_dot))
+    return false;
+
   if (!full && (a.GetDirectory().IsEmpty() || b.GetDirectory().IsEmpty()))
-    return ConstString::Equals(a.m_filename, b.m_filename, case_sensitive);
+    return filenames_equal;
 
   if (remove_backups == false)
     return a == b;