[PyTorch] Fix missing move in unpickler (#63974)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/63974

Saw some time spent in this for model loading, no reason not to move here.
ghstack-source-id: 136760979

Test Plan: Re-profile model loading on devserver; IValue copy ctor time has gone down

Reviewed By: dhruvbird

Differential Revision: D30548923

fbshipit-source-id: 42000f2e18582762b43353cca10ae094833de3b3

diff --git a/torch/csrc/jit/serialization/unpickler.cpp b/torch/csrc/jit/serialization/unpickler.cpp
index f944387..b521dc8 100644 (file)
--- a/torch/csrc/jit/serialization/unpickler.cpp
+++ b/torch/csrc/jit/serialization/unpickler.cpp
@@ -318,7 +318,7 @@ PickleOpCode Unpickler::readInstruction() {
       tuple->elements().reserve(stack_.size() - start);
       auto start_it = stack_.begin() + start;
       for (auto it = start_it; it != stack_.end(); ++it) {
-        tuple->elements().emplace_back(*it);
+        tuple->elements().emplace_back(std::move(*it));
       }
       stack_.erase(start_it, stack_.end());
       stack_.emplace_back(std::move(tuple));