Lightning Talk: Saturday Is Coming Faster - Convert year_month_day to Weekday Faster - Part 1
summary
Claims up to 3× faster conversion from year_month_day to weekday, with a concrete algorithm and assembly evidence rather than handwaving. Implementation exists in libstdc++ and performance is shown by inspecting generated code: a multiply-shift trick replaces slow mod 7, producing as little as six instructions (sometimes three operations plus a removed comparison). It requires a tight input range precondition so it is not a drop‑in replacement but is dramatically faster where applicable.
AI-written summary · about
related talks
06mLightning Talk: A Compiler Optimization and the 2-Adic Numbers
12mLightning Talk: Expected Application of BeamAsm
01h 00mFloating-Point ＜charconv＞: Making Your Code 10x Faster With C++17's Final Boss
01h 01mMoving to C++20 for Fun, Beauty... and Results!
06mLightning Talk Slot #4: Modularizing GHC
05mLightning Talk: Simple Compile Time Dynamic Programming
01mTalk Preview: A new dragon in the den: fast conversion from floating-point numbers
01h 07mC++20 Concepts: A Day in the Life