> On 10 Nov 2025, at 01:39, Jason Merrill <[email protected]> wrote:
>
> On 11/10/25 4:17 PM, Jakub Jelinek wrote:
>> On Mon, Nov 10, 2025 at 03:48:01PM +0530, Jason Merrill wrote:
>>> On 11/10/25 12:06 PM, Jakub Jelinek wrote:
>>>> Trivial relocation was voted out of C++26, the following patch
>>>> removes it (note, the libstdc++ part was still waiting for patch review
>>>> and so doesn't need to be removed).
>>>>
>>>> This isn't a mere revert of r16-2206; I've kept -Wc++26-compat option,
>>>> from earlier patches the non-terminal stays to be class-property-specifier,
>>>> and I had to partially revert also various follow-up changes, e.g. for
>>>> modules to handle the new flags and test them, for -Wkeyword-macro
>>>> etc. to diagnose the conditional keywords or the feature test macro
>>>> etc.
>>>>
>>>> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>>>
>>> I think I would prefer to just remove it from -std=c++26, it's expected to
>>> come back in C++29. Maybe give it a -ftrivial-relocation for now?
>> Is it worth that though, especially because it is incomplete, as opposed to
>> just starting from the revert commit again when something is agreed for
>> C++29?
>> The point is that the libstdc++ part has not been reviewed (
>> https://gcc.gnu.org/pipermail/libstdc++/2025-September/063523.html
>> is the latest version), so all we have on the compiler side is:
>> 1) __cpp_trivial_relocation predefined macro
>> 2) parsing the {trivially_relocatable,replaceable}_if_eligible conditional
>> keywords for C++26
>> 3) parsing the __{trivially_relocatable,replaceable}_if_eligible conditional
>> keywords
>> 4) the builtin traits (__builtin_is_*)
>> So, users can use the keywords but I think we don't want to encourage them
>> to use the __builtin_is_* functions directly. I think at least 2) shouldn't
>> be done for -std=c++26 (or if we really want -ftrivial-relocation),
>> similarly the pedantic -Wkeyword-macro etc. stuff.
>
> Hmm, I guess that makes sense. The patch is OK.
In that case, I guess it would be good to have it on a branch somewhere so
that people can experiment with it - on the assumption that there are
contentious
aspects that could be resolved by trial usage.
Iain
>
> Jason
