forked from abseil/abseil-cpp
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
PR abseil#1625: absl::is_trivially_relocatable now respects assignmen…
…t operators Imported from GitHub PR abseil#1625 Trivial relocatability also requires that the type not do anything weird with its assignment operator; update the type-trait to reflect this. (This is the definition used by BSL, Folly, HPX, Thrust, Parlay, Amadeus, and P1144.) This is important if we want to use `absl::is_trivially_relocatable` as a gate for memcpy optimizations in `inlined_vector::erase` and/or `inlined_vector::swap`, because in those cases relocation is used to replace part of a sequence involving assignment; the optimization requires an assignment operator that behaves value-semantically. Clang's builtin currently fails to check the assignment operator, so we stop using it entirely for now. We already refused to use it on Win32, Win64, and Apple, for various unrelated reasons. I'm working on giving Clang's builtin the behavior that would let us re-enable it here. Assume that any compiler providing both `__cpp_impl_trivially_relocatable` and a builtin `__is_trivially_relocatable(T)` will use the appropriate (P1144) definition for its builtin. Right now there's only one such compiler (the P1144 reference implementation, which forks Clang), so this is largely a moot point, but I'm being optimistic. Merge d943abd into 34604d5 Merging this change closes abseil#1625 COPYBARA_INTEGRATE_REVIEW=abseil#1625 from Quuxplusone:trivially-relocatable d943abd PiperOrigin-RevId: 607977323 Change-Id: I6436a60326c6d1064bdd71ec2e15b86b7a29efd4
- Loading branch information
1 parent
7b7f840
commit af87d19
Showing
2 changed files
with
70 additions
and
39 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters