> In modern times, modern compilers can perform all kinds of optimizations, including this one. So it’s up to you to decide if making things harder to read is worth it.
It is still worthwhile to manually perform these arithmetic optimizations because you may want to build with optimizations off and switching to actual multiplication in hot code paths can cause performance regressions.
An unrelated area where I wouldn't do this sort of thing is bit twiddling tricks to implement branchless code. That generally defeats modern compilers' abilities to generate branchless code with conditional moves and ends up being slower.
It is still worthwhile to manually perform these arithmetic optimizations because you may want to build with optimizations off and switching to actual multiplication in hot code paths can cause performance regressions.
An unrelated area where I wouldn't do this sort of thing is bit twiddling tricks to implement branchless code. That generally defeats modern compilers' abilities to generate branchless code with conditional moves and ends up being slower.