[X-POST] Alignas broken when used with constexpr array data member for structure

[Alec Teal]

More specific please, there's a lot in here.

For example I had a look in constexpr - seems like a good place to 
start! 7k lines; things may have moved.

It seems I might have been wrong, I need more than a directory!

I'm currently trying to set a breakpoint where errors are emitted (and 
hopefully find something on the stack, even if it's a function doing the 
passes!) - it's hard to find!

Usually I'd take more of a guess but this bug means I'm very far off the 
mark with the implementation.

Alec


On 09/01/18 13:40, Jonathan Wakely wrote:
> And I've now told you both on IRC and in reply to your original email,
> the directory is gcc/cp
>
> On 9 January 2018 at 13:39, Alec Teal <a.teal@warwick.ac.uk> wrote:
>> Per recommendation asking on GCC help
>>
>>
>>
>> -------- Forwarded Message --------
>> Subject:        Alignas broken when used with constexpr array data member
>> for structure
>> Date:   Tue, 9 Jan 2018 13:15:37 +0000
>> From:   Alec Teal <a.teal@warwick.ac.uk>
>> To:     gcc@gcc.gnu.org <gcc@gcc.gnu.org>
>>
>>
>>
>> [This sender failed our fraud detection checks and may not be who they
>> appear to be. Learn about spoofing at http://aka.ms/LearnAboutSpoofing]
>>
>>
>> Hi there,
>>
>> In GCC 4.8.4 I have something like the following:
>>
>> constexpr int x = 5;
>>
>> constexpr int y = 4;
>>
>> struct alignas(y) my_data_block {
>>
>>     char data[x];
>>
>> };
>>
>>
>> And it causes some weird errors to the tune of "size of array ‘data’ is
>> not an integral constant-expression" in the presence of the alignas
>>
>> This is a pretty nasty bug and means it's not implemented as I thought.
>> I don't know the front-ends (but I do actually know GIMPLE-low and below
>> quite well, love the pattern matching) and I'd like to dig more, it's
>> almost certainly fixed - this is just for personal curiosity.
>>
>> Where would I look? A 1 line reply with a directory would be a great
>> start; even if it's just a guess.
>>
>> I did ask in #gcc on freenode - it didn't go so well, sorry to ping you
>> all for this.
>>
>>
>> Alec
>>