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.
Jason
