C++ Unnecessary Objects

Recommendations

Compiler warnings

• -Wexit-time-destructors (Clang)
• -Wglobal-constructors (Clang)
• -Wpessimizing-move
• -Wrange-loop-construct

Clang-tidy checks

• performance-unnecessary-value-param
• performance-unnecessary-copy-initialization
• performance-for-range-copy
• modernize-pass-by-value
• performance-inefficient-vector-operation
• performance-noexcept-move-constructor
• modernize-use-emplace

Key points

• In-place construction without copies or moves
• Pass non-trivial objects by reference
• Use view types ( std::string_view , std::span )
• Use in-place constructors for STL types
• Use emplace
• Use transparent comparators for std::string in associative containers
• Move data to compile time
• Use clang-tidy checks and warnings

Reference

• C++ Performance Tips - Cutting Down on Unnecessary Objects - Prithvi Okade & Kathleen Baker
• GCC Warning Options
• Diagnostic flags in Clang
• Clang-Tidy Checks