On Wed, Jun 27, 2007 at 09:34:55AM -0700, Josh Triplett wrote: > > is actually nice code for something like the kernel, but it turns out that > > in order to make this work, you have to do it as > > > > #define htons(x) (__builtin_constant_p(x) ? constant_htons(x) : > > __htons(x))
That's not quite right. In principle, __builtin_choose_expr() could be used for that kind of stuff and builtins can change the rules. > Also agreed. Same goes for other short-circuiting operations like &&, > ||, and ?: without the center argument; if you can determine at > compilation time that it does not need to evaluate part of the > expression at all, go ahead and ignore that part of the expression even > if it does not constitute an integer constant expression. If you want > to optionally check for this case and issue a diagnostic, put it under > -Wstrict-constant-expressions or similar. That actually means extra work for evaluate_expression(). Unfortunately. The thing is, we want to typecheck all branches, even ones not taken. _However_, we don't want to expand all of them. Having extra places where we have to do expansion means extra work. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
