I have created a separate bugzilla for it: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120994
On Tue, Jul 8, 2025 at 9:58 AM Luc Grosheintz <luc.groshei...@gmail.com> wrote: > How would you like to track this on bugzilla: > > 1. As part of submdspan: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110352 > https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p2630r4.html > > 2. As a new issue, because it's a different paper: > https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2024/p2897r7.html > > On 7/3/25 12:33, Luc Grosheintz wrote: > > This patch series implements the aligned_accessor paper P2897R7 in three > > parts: > > > > - Implement `is_sufficiently_aligned` which is part of <memory>. > > - Prepare the accessor tests for reuse. > > - Implement aligned_accessor. > > > > A couple of remarks: > > > > - The paper P2897R7 and spec N5008 don't specify that the aligment > > for is_sufficiently_aligned must be a power of two. > > > > - The reasoning for why is_sufficiently_aligned isn't constexpr is > > nicely described in the paper. > > > > - Use of `class` in is_sufficiently_aligned is for consistency within > > that file. > > > > - The tests create new unsupported tests and expected failures. The > > testsuite doesn't have all that many of those; so there's likely a > > strategy to avoid this. However, I don't know how. > > > > - These changes are independent of mdspan, but due to the precise > > location of the code it might conflict with the mdspan patch series. > > > > - I skipped updating `cxxapi-data.csv` for is_sufficiently_aligned > > due to consistency with the rest of the mdspan patches, i.e. there > > will be a bulk update of the file later. > > > > - Each commit was tested with/without PCH and with/without > > _GLIBCXX_DEBUG filtered by 20_util/is_sufficiently_aligned > > and 23_containers/mdspan. > > The last commit was tested fully with/without PCH. All tests on > > x86_64-linux. > > > > As always I'm happy to reorganize into different commits, if the > > grouping doesn't make sense. > > > > Luc Grosheintz (3): > > libstdc++: Implement is_sufficiently_aligned. > > libstdc++: Prepare test code for default_accessor for reuse. > > libstdc++: Implement aligned_accessor from mdspan. > > > > libstdc++-v3/include/bits/align.h | 16 ++ > > libstdc++-v3/include/bits/version.def | 18 ++ > > libstdc++-v3/include/bits/version.h | 20 +++ > > libstdc++-v3/include/std/mdspan | 72 ++++++++ > > libstdc++-v3/include/std/memory | 1 + > > libstdc++-v3/src/c++23/std.cc.in | 4 +- > > .../20_util/is_sufficiently_aligned/1.cc | 31 ++++ > > .../20_util/is_sufficiently_aligned/2.cc | 7 + > > .../23_containers/mdspan/accessors/aligned.cc | 43 +++++ > > .../mdspan/accessors/aligned_ftm.cc | 6 + > > .../mdspan/accessors/aligned_neg.cc | 33 ++++ > > .../accessors/debug/aligned_access_neg.cc | 23 +++ > > .../accessors/debug/aligned_offset_neg.cc | 23 +++ > > .../23_containers/mdspan/accessors/default.cc | 99 ----------- > > .../23_containers/mdspan/accessors/generic.cc | 168 ++++++++++++++++++ > > 15 files changed, 464 insertions(+), 100 deletions(-) > > create mode 100644 > libstdc++-v3/testsuite/20_util/is_sufficiently_aligned/1.cc > > create mode 100644 > libstdc++-v3/testsuite/20_util/is_sufficiently_aligned/2.cc > > create mode 100644 > libstdc++-v3/testsuite/23_containers/mdspan/accessors/aligned.cc > > create mode 100644 > libstdc++-v3/testsuite/23_containers/mdspan/accessors/aligned_ftm.cc > > create mode 100644 > libstdc++-v3/testsuite/23_containers/mdspan/accessors/aligned_neg.cc > > create mode 100644 > libstdc++-v3/testsuite/23_containers/mdspan/accessors/debug/aligned_access_neg.cc > > create mode 100644 > libstdc++-v3/testsuite/23_containers/mdspan/accessors/debug/aligned_offset_neg.cc > > delete mode 100644 > libstdc++-v3/testsuite/23_containers/mdspan/accessors/default.cc > > create mode 100644 > libstdc++-v3/testsuite/23_containers/mdspan/accessors/generic.cc > > > >
