Note 11, DM546, fall 2019

Exercises March 22

• Cover the most important exercises left over from previous sessions. Then briefly talk about the discussion points below:
• Consider possible targets for optimization other than time and space and describe plausible goals.
• Try to find patterns which could be used in a high-level peep-hole optimization of for instance C-programs. Are there any possible dangers in writing a high-level optimizer for C-programs where simple but inefficient code is replaced by more complicated but also more efficient code?
• Take a look at code generated by gcc (compile with gcc -S) for a few well-known and relatively short source files, such as factorial, for instance. Try to investigate the effect of the three options -O1, -O2, and -O3 with regards to code optimization.
• Find more peephole patterns in the categories from the lecture or from new catagories that you come up with.