pytorch

79e10ce9 - [PyTorch] Construct IValue from List without copies in args (#52325)

[PyTorch] Construct IValue from List without copies in args (#52325) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/52325 List's move constructor is comparatively expensive (copies the type) and so is its destructor (has to destroy the type, which isn't null). So, it's best not to create intermediate `List` objects in function parameters. Copy elision won't save us here; it's not allowed to! (see https://en.cppreference.com/w/cpp/language/copy_elision) ghstack-source-id: 121807291 Test Plan: Profile AdIndexer benchmark. Time spent in push_outputs is down from 0.2% to 0.01%. Inspecting assembly for `c10::impl::push_outputs<c10::List<at::Tensor>,false>::call` shows that we have gone from 2 List move ctor calls and 3 ~instrusive_ptr dtor calls to 0 calls and 1 call, respectively. Reviewed By: bhosmer Differential Revision: D26471092 fbshipit-source-id: 412a85fcc36d141fb91710c7855df24c137813a9