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On 09/04/17 10:07, Bernd Edlinger wrote:
> Hi,
>
> as you know we have a -Wcast-align warning which works only for
> STRICT_ALIGNMENT targets. But occasionally it would be nice to be
> able to switch this warning on even for other targets.
>
> Therefore I would like to add a strict version of this option
> which can be invoked with -Wcast-align=strict. With the only
> difference that it does not depend on STRICT_ALIGNMENT.
>
> I used the code from check_effective_target_non_strict_align
> in target-supports.exp for the first version of the test case,
> where we have this:
>
> return [check_no_compiler_messages non_strict_align assembly {
> char *y;
> typedef char __attribute__ ((__aligned__(__BIGGEST_ALIGNMENT__))) c;
> c *z;
> void foo(void) { z = (c *) y; }
> } "-Wcast-align"]
>
> ... and to my big surprise it did _not_ work for C++ as-is,
> because same_type_p considers differently aligned types identical,
> and therefore cp_build_c_cast tries the conversion first via a
> const_cast which succeeds, but did not emit the cast-align warning
> in this case.
>
> As a work-around I had to check the alignment in build_const_cast_1
> as well.
>
>
> Bootstrapped and reg-tested on x86_64-pc-linux-gnu.
> Is it OK for trunk?
>
>
> Thanks
> Bernd.
>
