This does far more than I did back in my PET and then Amiga days, but one thing I did was write a multi-pass compiler. Each pass at first found ways to make the come better (usually smaller so it ran faster). Even simple code I wrote could see a 10-20% improvement.
Of-course, this is because the original code was quick and dirty. I wonder what improvement modern compilers could have added.
Of-course, this is because the original code was quick and dirty. I wonder what improvement modern compilers could have added.