fix hash generation for 64bit processors

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@38294 72102866-910b-0410-8b05-ffd578937521

Source/NSObject.m

@@ -1902,13 +1902,16 @@ static id gs_weak_load(id obj)
 - (NSUInteger) hash
 {
   /*
-   * Ideally we would shift left to lose any zero bits produced by the
+   *  malloc() must return pointers aligned to point to any data type
-   * alignment of the object in memory ... but that depends on the
-   * processor architecture and the memory allocatiion implementation.
-   * In the absence of detailed information, pick a reasonable value
-   * assuming the object will be aligned to an eight byte boundary.
    */
-  return (NSUInteger)(uintptr_t)self >> 3;
+#define MAXALIGN (__alignof__(_Complex long double))
+
+  static int shift = MAXALIGN==16 ? 4 : (MAXALIGN==8 ? 3 : 2);
+
+  /* We shift left to lose any zero bits produced by the
+   * alignment of the object in memory.
+   */
+  return (NSUInteger)((uintptr_t)self >> shift);
 }
 
 /**