Why are compilers so stupid?

Question

I always wonder why compilers can\'t figure out simple things that are obvious to the human eye. They do lots of simple optimizations, but never something even a little bit

Answer 1

I hate to bring this up on such an old question (how did I get here, anyway?), but I think part of this might be something of a holdout from the days of the Commodore 64.

In the early 1980s, everything ran on a fixed clock. There was no Turbo Boosting and code was always created for a specific system with a specific processor and specific memory, etc. In Commodore BASIC, the standard method for implementing delays looked a lot like:

10 FOR X = 1 TO 1000
20 NEXT : REM 1-SECOND DELAY

(Actually, in practice, it more closely resembled 10FORX=1TO1000:NEXT, but you know what I mean.)

If they were to optimize this, it would break everything—nothing would ever be timed. I don't know of any examples, but I'm sure there are lots of little things like this scattered through the history of compiled languages that prevented things from being optimized.

Admittedly, these non-optimizations aren't necessary today. There's probably, however, some unspoken rule among compiler developers not to optimize things like this. I wouldn't know.

Just be glad that your code is optimized somewhat, unlike code on the C64. Displaying a bitmap on the C64 could take up to 60 seconds with the most efficient BASIC loops; thus, most games, etc. were written in machine language. Writing games in machine language isn't fun.

Just my thoughts.