On Thu, 17 Jul 2025, Jonathan Wakely wrote: > On 17/07/25 15:31 +0200, Tomasz Kamiński wrote: > > From: Jonathan Wakely <jwak...@redhat.com> > > > > Implement std::inplace_vector as specified in P0843R14, without follow > > up papers, in particular P3074R7 (trivial unions). In consequence > > inplace_vector<T, N> can be used inside constant evaluations only > > if T is trivial of N is equal to zero. > > > > We provide a separate specialization for inplace_vector<T, 0> to meet > > the requirements of N5008 [inplace.vector.overview] p5. In particular > > objects of such types needs to be empty. > > > > To allow contexpr variable of inplace_vector v, where v.size() < > > v.capacity(), > > we need to guaranteed that all elements of the storage array are > > initialized, > > even ones in range [v.data() + v.size(), v.data() + v.capacity()). This is > > perfomed by _M_init function, that is alled by each constructored. By > > storing > > the array in animous union, we can perform this intialization in constant > > evaluation, avoiding the impact on runtime path. > > > > The size() function conveys the information that _M_size <= _Nm to compiler, > > by calling __builtin_unreachable(). In particular this allows us to > > eliminate > > FP warnings by using _Nm - size() instead of _Nm - _M_size, when computing > > available elements. > > > > However, we still have one -Waggressive-loop-optimizations (to best of our > > knowledge false-positive warning produced in cons/from_range.cc and > > cons/throws.cc. Currently it is pruned using dg-prune-output and tracked by > > PR121143. > > > > The included test cover almost all code paths at runtime, however some > > compile time evaluation test are not yet implemented: > > * operations on range, they depenend on making testsuite_iterators constexpr > > * negative test for invoking operations with preconditions at compile time, > > especially for zero size specialization. > > > > PR libstdc++/119137 > > > > libstdc++-v3/ChangeLog: > > > > * doc/doxygen/user.cfg.in (INPUT): Add new header. > > * include/Makefile.am: Add new header. > > * include/Makefile.in: Regenerate. > > * include/bits/version.def (inplace_vector): Define. > > * include/bits/version.h: Regenerate. > > * include/precompiled/stdc++.h: Include new header. > > * src/c++23/std.cc.in: Export contents if new header. > > * include/std/inplace_vector: New file. > > * testsuite/23_containers/inplace_vector/access/capacity.cc: New file. > > * testsuite/23_containers/inplace_vector/access/elem.cc: New file. > > * testsuite/23_containers/inplace_vector/access/elem_neg.cc: New file. > > * testsuite/23_containers/inplace_vector/cons/1.cc: New file. > > * testsuite/23_containers/inplace_vector/cons/from_range.cc: New file. > > * testsuite/23_containers/inplace_vector/cons/throws.cc: New file. > > * testsuite/23_containers/inplace_vector/copy.cc: New file. > > * testsuite/23_containers/inplace_vector/erasure.cc: New file. > > * testsuite/23_containers/inplace_vector/modifiers/assign.cc: New > > file. > > * testsuite/23_containers/inplace_vector/modifiers/erase.cc: New file. > > * testsuite/23_containers/inplace_vector/modifiers/multi_insert.cc: > > New file. > > * testsuite/23_containers/inplace_vector/modifiers/single_insert.cc: > > New file. > > * testsuite/23_containers/inplace_vector/move.cc: New file. > > * testsuite/23_containers/inplace_vector/relops.cc: New file. > > * testsuite/23_containers/inplace_vector/version.cc: New file. > > * testsuite/util/testsuite_iterators.h (input_iterator_wrapper::base): > > Define. > > > > Co-authored-by: Tomasz Kamiński <tkami...@redhat.com> > > Signed-off-by: Tomasz Kamiński <tkami...@redhat.com> > > --- > > Jonathan have provided initial implementation, that I (Tomasz) have > > later finished and extended the test coverate. Details can be found at: > > https://forge.sourceware.org/gcc/gcc-TEST/pulls/58 > > > > Tested on x86_64-linux. OK for trunk? > > OK for trunk with the typos in the commit msg fixed, and the redundant > header remove that Patrick noticed.
I don't know why Gmail decided to garble my mail by wrapping it to 80 characters but I also have some other review comments in there.
