move dont swap

VowpalWabbit · Aug 15, 2023 · 8a1a524 · 8a1a524
1 parent b6ece99
commit 8a1a524
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Showing 3 changed files with 21 additions and 19 deletions.
diff --git a/vowpalwabbit/core/include/vw/core/example.h b/vowpalwabbit/core/include/vw/core/example.h
@@ -83,7 +83,7 @@ class polyprediction
 };
 
 std::string to_string(const v_array<float>& scalars, int decimal_precision = details::DEFAULT_FLOAT_PRECISION);
-void swap_prediction(polyprediction& a, polyprediction& b, prediction_type_t prediction_type);
+void move_pred_to(polyprediction& src, polyprediction& dest, prediction_type_t prediction_type);
 
 class example : public example_predict  // core example datatype.
 {

diff --git a/vowpalwabbit/core/src/example.cc b/vowpalwabbit/core/src/example.cc
@@ -16,45 +16,45 @@
 #include <climits>
 #include <cstdint>
 
-void VW::swap_prediction(VW::polyprediction& a, VW::polyprediction& b, VW::prediction_type_t prediction_type)
+void VW::move_pred_to(VW::polyprediction& src, VW::polyprediction& dest, VW::prediction_type_t prediction_type)
 {
-  switch(prediction_type)
+  switch (prediction_type)
   {
     case VW::prediction_type_t::SCALAR:
-      std::swap(a.scalar, b.scalar);
+      dest.scalar = std::move(src.scalar);
       break;
     case VW::prediction_type_t::SCALARS:
-      std::swap(a.scalars, b.scalars);
+      dest.scalars = std::move(src.scalars);
       break;
     case VW::prediction_type_t::ACTION_SCORES:
-      std::swap(a.a_s, b.a_s);
+      dest.a_s = std::move(src.a_s);
       break;
     case VW::prediction_type_t::PDF:
-      std::swap(a.pdf, b.pdf);
+      dest.pdf = std::move(src.pdf);
       break;
     case VW::prediction_type_t::ACTION_PROBS:
-      std::swap(a.a_s, b.a_s);
+      dest.a_s = std::move(src.a_s);
       break;
     case VW::prediction_type_t::MULTICLASS:
-      std::swap(a.multiclass, b.multiclass);
+      dest.multiclass = std::move(src.multiclass);
       break;
     case VW::prediction_type_t::MULTILABELS:
-      std::swap(a.multilabels, b.multilabels);
+      dest.multilabels = std::move(src.multilabels);
       break;
     case VW::prediction_type_t::PROB:
-      std::swap(a.prob, b.prob);
+      dest.prob = std::move(src.prob);
       break;
     case VW::prediction_type_t::MULTICLASS_PROBS:
-      std::swap(a.scalars, b.scalars);
+      dest.scalars = std::move(src.scalars);
       break;
     case VW::prediction_type_t::DECISION_PROBS:
-      std::swap(a.decision_scores, b.decision_scores);
+      dest.decision_scores = std::move(src.decision_scores);
       break;
     case VW::prediction_type_t::ACTION_PDF_VALUE:
-      std::swap(a.pdf_value, b.pdf_value);
+      dest.pdf_value = std::move(src.pdf_value);
       break;
     case VW::prediction_type_t::ACTIVE_MULTICLASS:
-      std::swap(a.active_multiclass, b.active_multiclass);
+      dest.active_multiclass = std::move(src.active_multiclass);
       break;
     case VW::prediction_type_t::NOPRED:
       // Noop

diff --git a/vowpalwabbit/core/src/global_data.cc b/vowpalwabbit/core/src/global_data.cc
@@ -93,9 +93,10 @@ void workspace::learn(example& ec)
     {
       VW::LEARNER::require_singleline(l)->predict(ec);
       VW::polyprediction saved_prediction;
-      VW::swap_prediction(saved_prediction, ec.pred, l->get_output_prediction_type());
+      VW::move_pred_to(ec.pred, saved_prediction, l->get_output_prediction_type());
+      new (&ec.pred) VW::polyprediction();
       VW::LEARNER::require_singleline(l)->learn(ec);
-      VW::swap_prediction(saved_prediction, ec.pred, l->get_output_prediction_type());
+      VW::move_pred_to(saved_prediction, ec.pred, l->get_output_prediction_type());
     }
   }
 }
@@ -112,9 +113,10 @@ void workspace::learn(multi_ex& ec)
     {
       VW::LEARNER::require_multiline(l)->predict(ec);
       VW::polyprediction saved_prediction;
-      VW::swap_prediction(saved_prediction, ec[0]->pred, l->get_output_prediction_type());
+      VW::move_pred_to(ec[0]->pred, saved_prediction, l->get_output_prediction_type());
+      new (&ec[0]->pred) VW::polyprediction();
       VW::LEARNER::require_multiline(l)->learn(ec);
-      VW::swap_prediction(saved_prediction, ec[0]->pred, l->get_output_prediction_type());
+      VW::move_pred_to(saved_prediction, ec[0]->pred, l->get_output_prediction_type());
     }
   }
 }