re PR middle-end/20493 (Bootstrap failure because of aliased symbols)

	PR middle-end/20493
	* fold-const.c (fold_widened_comparison): Don't optimize casts of
	function pointers on targets that require function pointer
	canonicalization.
	(fold_sign_changed_comparison): Likewise.

From-SVN: r96733

gcc/ChangeLog

+2005-03-19  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
+
+	PR middle-end/20493
+	* fold-const.c (fold_widened_comparison): Don't optimize casts of
+	function pointers on targets that require function pointer
+	canonicalization.
+	(fold_sign_changed_comparison): Likewise.
+
 2005-03-19  Bernd Schmidt  <bernd.schmidt@analog.com>
 
 	* combine.c (try_combine): When changing the mode of a hard reg, make

gcc/fold-const.c

@@ -6074,6 +6074,15 @@ fold_widened_comparison (enum tree_code code, tree type, tree arg0, tree arg1)
     return NULL_TREE;
   shorter_type = TREE_TYPE (arg0_unw);
 
+#ifdef HAVE_canonicalize_funcptr_for_compare
+  /* Disable this optimization if we're casting a function pointer
+     type on targets that require function pointer canonicalization.  */
+  if (HAVE_canonicalize_funcptr_for_compare
+      && TREE_CODE (shorter_type) == POINTER_TYPE
+      && TREE_CODE (TREE_TYPE (shorter_type)) == FUNCTION_TYPE)
+    return NULL_TREE;
+#endif
+
   if (TYPE_PRECISION (TREE_TYPE (arg0)) <= TYPE_PRECISION (shorter_type))
     return NULL_TREE;
 
@@ -6156,6 +6165,15 @@ fold_sign_changed_comparison (enum tree_code code, tree type,
   arg0_inner = TREE_OPERAND (arg0, 0);
   inner_type = TREE_TYPE (arg0_inner);
 
+#ifdef HAVE_canonicalize_funcptr_for_compare
+  /* Disable this optimization if we're casting a function pointer
+     type on targets that require function pointer canonicalization.  */
+  if (HAVE_canonicalize_funcptr_for_compare
+      && TREE_CODE (inner_type) == POINTER_TYPE
+      && TREE_CODE (TREE_TYPE (inner_type)) == FUNCTION_TYPE)
+    return NULL_TREE;
+#endif
+
   if (TYPE_PRECISION (inner_type) != TYPE_PRECISION (outer_type))
     return NULL_TREE;