------- Comment #6 from jobnoorman at gmail dot com 2010-08-17 10:49 -------
(In reply to comment #5)
> For inline-asm? Certainly not. Consider much simpler:
> void foo (void)
> {
> int i;
> i = 6;
> asm volatile ("" : : "i" (i));
> }
> which will work with -O and above, but not for -O0, for exactly the same
> reason.
IMHO, your example should always give an error. The "i" constraint is to be
used for constant integer operands. A variable of type "int" just isn't
constant, even if GCC is smart enough to optimize the variable away and use a
constant instead. Your example will always work if you make "i" of type "const
int".
I also think there is an important difference between your example and mine:
the expression "(plain_foobar_t)&Foo::foobar" is a constant expression (please
correct me if I'm wrong) and thus should always be allowed when using the "i"
constraint.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45303
