2008-01-31 Douglas Gregor <doug.gregor@gmail.com>

[pf3gnuchains/gcc-fork.git] / gcc / cp / typeck.c

diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index fd2a319..4d6e06b 100644 (file)
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -977,6 +977,30 @@ structural_comptypes (tree t1, tree t2, int strict)
   /* Compare the types.  Break out if they could be the same.  */
   switch (TREE_CODE (t1))
     {
+    case VOID_TYPE:
+    case BOOLEAN_TYPE:
+      /* All void and bool types are the same.  */
+      break;
+
+    case INTEGER_TYPE:
+    case FIXED_POINT_TYPE:
+    case REAL_TYPE:
+      /* With these nodes, we can't determine type equivalence by
+        looking at what is stored in the nodes themselves, because
+        two nodes might have different TYPE_MAIN_VARIANTs but still
+        represent the same type.  For example, wchar_t and int could
+        have the same properties (TYPE_PRECISION, TYPE_MIN_VALUE,
+        TYPE_MAX_VALUE, etc.), but have different TYPE_MAIN_VARIANTs
+        and are distinct types. On the other hand, int and the
+        following typedef
+
+           typedef int INT __attribute((may_alias));
+
+        have identical properties, different TYPE_MAIN_VARIANTs, but
+        represent the same type.  The canonical type system keeps
+        track of equivalence in this case, so we fall back on it.  */
+      return TYPE_CANONICAL (t1) == TYPE_CANONICAL (t2);
+
     case TEMPLATE_TEMPLATE_PARM:
     case BOUND_TEMPLATE_TEMPLATE_PARM:
       if (TEMPLATE_TYPE_IDX (t1) != TEMPLATE_TYPE_IDX (t2)