In 2012, we were debating which of the new C++11 features could be adopted as part of the canon of acceptable coding practices. Being fastest is great, but not having bugs is even more important.

Obviously, nicely written, testable code is extremely importantespecially if that code has the potential to make thousands of financial transactions per second. Just as before, knowing what the compiler was doing with code helped inform the way we wrote the code. Writing custom assembly, and reading the compiler output to see what it was capable of, was par for the course.įast-forward five years and I was at a trading company, having switched out sprites and polygons for fast processing of financial data. I spent a decade making video games where every CPU cycle counted in the war to get more sprites, explosions, or complicated scenes on the screen than our competitors. I have always been fascinated by what compilers are capable of. Indeed, the advent of front-end-agnostic compiler toolkits such as LLVM 3 means most of these optimizations work in the exact same way in languages such as Rust, Swift, and D. The examples shown here are in C or C++, which are the languages I have had the most experience with, but many of these optimizations are also available in other compiled languages. Most of all, you may learn to love looking at the assembly output and may learn to respect the quality of the engineering in your compilers. I hope you will gain an appreciation for what kinds of optimizations you can expect your compiler to do for you, and how you might explore the subject further. This article introduces some compiler and code generation concepts, and then shines a torch over a few of the very impressive feats of transformation your compilers are doing for you, with some practical demonstrations of my favorite optimizations. You may spend a lot of time carefully considering algorithms and fighting error messages but perhaps not enough time looking at what compilers are capable of doing. Their sophistication at doing this is often overlooked. Compilers are a necessary technology to turn high-level, easier-to-write code into efficient machine code for computers to execute.

Codeblocks compiler optimization flags