5 ms·

Why can't the compiler optimize this?

• to3m 15y ago
  Theoretically, it could do, at least in this case, I think? Very risky to rely on that though! I doubt compiler writers have people who haven't heard of the switch statement in mind when they decide which optimizations to put in. (The "fast" branch uses a switch statement - I guess the author is going for minimum number of lines in this one? I'm not sure saving 2-3 lines compared to a squeezed-together switch statement is a great tradeoff, though. You could get better results by just putting everything in one source file. Easier deployment, too. I bet it wouldn't affect readability significantly.)
• ori_b 15y ago
  It can. However, this is a very uncommon pattern, so it's not worth trying very hard to detect. On top of that, I'd expect the compiler to bail after the pattern gets to a certain size.