3 ms·

I forgot to do this last night. I think the compiler is able to apply the optimization in many cases even if the loop variable is unsigned, so it’s more accurat

I forgot to do this last night. I think the compiler is able to apply the optimization in many cases even if the loop variable is unsigned, so it’s more accurate to say that a pessimization is added when the compiler has to account for overflow. If the rant had said the pessimization wasn’t all that common, or that a decent programmer should ask “how can I go through this loop fewer times?” before asking “how can I speed up each time through the loop?” I wouldn’t consider it a rant. As it is, the writer acknowledges that the other side has an argument, and then he dismisses it with a hand wave and a “supposedly.”

vyodaiken 8y ago
So "rant" is an unnecessary pejorative. Try to make your case without yelling. And I don't get your point. You have just agreed that the compiler can optimize these loops without UB. The pessimization is minor and programmer choice. So what is the argument on the other side ? How do you justify a code transformation that, e.g. produces an infinite loop by removing a programmer check for a condition that actually can occur?
- maxlybbert 8y ago
  I don’t think that saying “the article is a rant because it doesn’t make a serious effort to respond to counterguments” qualifies as yelling. As for my point: in my opinion, the title promised something interesting, but the article didn’t deliver. It acknowledged that the standard committee and compiler writers disagree with its premise, but then simply asserts that the committee and compiler writers are wrong. I put it at DH3 ( http://www.paulgraham.com/disagree.html http://www.paulgraham.com/disagree.html ).
- maxlybbert 8y ago
  If I claim somebody is ranting and raving, I’m not claiming anything about whether I’m yelling, but whether they are. Of course, “rant” has more than one meaning. I did not mean “the writer should be held in a mental institution as a threat to themself or others,” or even “writer should feel embarrassed and ashamed for publishing this.” I meant “article makes statements that generally aren’t supported by valid arguments.” I then gave an example that (1) was not the only case of a supporting argument not actually supporting the claim, and (2) perhaps wasn’t completely fair. But first, a story: Recently, one of my sons had diarrhea. He complained that his sister made him sick, since she had just recovered from a cold. He never understood why we rejected that argument (yes, people with colds can give other people colds, but he didn’t have a cold), and then told him he didn’t have anything to support his claim. As far as he was concerned, he had made something that looked like a valid argument: his sister had a cold, now he was sick, q.e.d. So when I said that the statement “‘supposed’ optimization” isn’t really an argument, but a statement that “there are people who disagree with me, but they’re wrong,” which isn’t a supporting argument — if anything, it’s a placeholder for a supporting argument — I forgot that the essay does advance one reason to reject the “‘supposed’ optimization,” but I rejected this reason (the issue about whether it’s slower to increment a value that has defined overflow than one that does not isn’t a question of whether the two values are the same size), and then said the statement had no support. It is true that at this point, I can provide other reasons to reject the compiler writers’ argument, but then the whole exercise feels like a psychic reading (writer: “I feel like blue will be important for my next argument, can you tell me why?” reader: “wow, that’s uncanny; blue is important ...”).

vyodaiken 8y ago

So "rant" is an unnecessary pejorative. Try to make your case without yelling. And I don't get your point. You have just agreed that the compiler can optimize these loops without UB. The pessimization is minor and programmer choice. So what is the argument on the other side ? How do you justify a code transformation that, e.g. produces an infinite loop by removing a programmer check for a condition that actually can occur?

maxlybbert 8y ago
I don’t think that saying “the article is a rant because it doesn’t make a serious effort to respond to counterguments” qualifies as yelling. As for my point: in my opinion, the title promised something interesting, but the article didn’t deliver. It acknowledged that the standard committee and compiler writers disagree with its premise, but then simply asserts that the committee and compiler writers are wrong. I put it at DH3 ( http://www.paulgraham.com/disagree.html http://www.paulgraham.com/disagree.html ).
maxlybbert 8y ago
If I claim somebody is ranting and raving, I’m not claiming anything about whether I’m yelling, but whether they are. Of course, “rant” has more than one meaning. I did not mean “the writer should be held in a mental institution as a threat to themself or others,” or even “writer should feel embarrassed and ashamed for publishing this.” I meant “article makes statements that generally aren’t supported by valid arguments.” I then gave an example that (1) was not the only case of a supporting argument not actually supporting the claim, and (2) perhaps wasn’t completely fair. But first, a story: Recently, one of my sons had diarrhea. He complained that his sister made him sick, since she had just recovered from a cold. He never understood why we rejected that argument (yes, people with colds can give other people colds, but he didn’t have a cold), and then told him he didn’t have anything to support his claim. As far as he was concerned, he had made something that looked like a valid argument: his sister had a cold, now he was sick, q.e.d. So when I said that the statement “‘supposed’ optimization” isn’t really an argument, but a statement that “there are people who disagree with me, but they’re wrong,” which isn’t a supporting argument — if anything, it’s a placeholder for a supporting argument — I forgot that the essay does advance one reason to reject the “‘supposed’ optimization,” but I rejected this reason (the issue about whether it’s slower to increment a value that has defined overflow than one that does not isn’t a question of whether the two values are the same size), and then said the statement had no support. It is true that at this point, I can provide other reasons to reject the compiler writers’ argument, but then the whole exercise feels like a psychic reading (writer: “I feel like blue will be important for my next argument, can you tell me why?” reader: “wow, that’s uncanny; blue is important ...”).