Avoid copy of intersection in totalTurnAngle (#6938)

Author: SiarheiFedartsou

CHANGELOG.md

@@ -24,6 +24,7 @@
     - NodeJS:
       - CHANGED: Use node-api instead of NAN. [#6452](https://github.com/Project-OSRM/osrm-backend/pull/6452)
     - Misc:
+      - CHANGED: Avoid copy of intersection in totalTurnAngle. [#6938](https://github.com/Project-OSRM/osrm-backend/pull/6938)
       - CHANGED: Use std::unordered_map::emplace instead of operator[] when producing JSONs. [#6936](https://github.com/Project-OSRM/osrm-backend/pull/6936)
       - CHANGED: Avoid copy of vectors in MakeRoute function. [#6939](https://github.com/Project-OSRM/osrm-backend/pull/6939)
       - FIXED: Fix bugprone-unused-return-value clang-tidy warning. [#6934](https://github.com/Project-OSRM/osrm-backend/pull/6934)

include/engine/guidance/collapsing_utility.hpp

@@ -202,8 +202,8 @@ inline double totalTurnAngle(const RouteStep &entry_step, const RouteStep &exit_
     if (entry_step.geometry_begin > exit_step.geometry_begin)
         return totalTurnAngle(exit_step, entry_step);
 
-    const auto exit_intersection = exit_step.intersections.front();
-    const auto entry_intersection = entry_step.intersections.front();
+    const auto &exit_intersection = exit_step.intersections.front();
+    const auto &entry_intersection = entry_step.intersections.front();
     if ((exit_intersection.out >= exit_intersection.bearings.size()) ||
         (entry_intersection.in >= entry_intersection.bearings.size()))
         return entry_intersection.bearings[entry_intersection.out];