On Tue, 21 Nov 2023 at 18:11, Marc Glisse <marc.gli...@inria.fr> wrote: > > On Tue, 21 Nov 2023, Jonathan Wakely wrote: > > > CC Marc Glisse who added the relocation support. He might recall why > > we use memmove when all uses are for newly-allocated storage, which > > cannot overlap the existing storage. > > Going back a bit: > > https://gcc.gnu.org/pipermail/gcc-patches/2019-April/520658.html > > "I think the call to memmove in __relocate_a_1 could probably be > memcpy (I don't remember why I chose memmove)" > > Going back a bit further: > > https://gcc.gnu.org/pipermail/gcc-patches/2018-September/505800.html > > "I had to add a special case for trivial types, using memmove, to avoid > perf regressions, since relocation takes precedence over the old path that > is specialized to call memmove." > > So the reason seems to be because vector already used memmove before my > patch. You can dig further if you want to check why that is ;-)
Thanks for the quick archaeology, Marc!
