system.h (CONST_CAST): Avoid union for gcc-4.0.x.

	* system.h (CONST_CAST): Avoid union for gcc-4.0.x.

From-SVN: r127878

gcc/ChangeLog

+2007-08-28  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+	* system.h (CONST_CAST): Avoid union for gcc-4.0.x.
+
 2007-08-28  Richard Guenther  <rguenther@suse.de>
 
 	* tree.h (struct tree_function_decl): Increase size of

gcc/system.h

@@ -774,7 +774,9 @@ extern void fancy_abort (const char *, int, const char *) ATTRIBUTE_NORETURN;
    execv, et al.  Another valid use would be in an allocation function
    that creates const objects that need to be initialized.  Most other
    cases should be viewed with extreme caution.  */
-#ifdef __GNUC__
+
+#if defined(__GNUC__) && GCC_VERSION != 4000
+/* GCC 4.0.x has a bug where it may ICE on this expression.  */
 #define CONST_CAST(X) ((__extension__(union {__typeof(X)_q; void *_v;})(X))._v)
 #else
 #define CONST_CAST(X) ((void*)(X))