On Sat, Jun 20, 2015 at 03:02:06AM +0300, Mikhail Maltsev wrote:
> - /* We do not warn for constants because they are typical of macro
> - expansions that test for features. */
> - if (CONSTANT_CLASS_P (op_left) || CONSTANT_CLASS_P (op_right))
> + /* We do not warn for literal constants because they are typical of macro
> + expansions that test for features. Likewise, we do not warn for
> + const-qualified and constexpr variables which are initialized by
> constant
> + expressions, because they can come from e.g. <type_traits> or similar
> user
> + code. */
> + if (TREE_CONSTANT (op_left) || TREE_CONSTANT (op_right))
> return;
That looks wrong, because with TREE_CONSTANT we'd warn in C but not in C++
for the following:
const int a = 4;
void
f (void)
{
const int b = 4;
static const int c = 5;
if (a && a) {}
if (b && b) {}
if (c && c) {}
}
Note that const-qualified types are checked using TYPE_READONLY.
But I'm not even sure that the warning in the original testcase in the PR
is bogus; you won't get any warning when using e.g.
foo<unsigned, signed>();
in main().
Marek
