state of a typical C compiler, 1998

[ratsnakegames@mastodon.social]

@joe the heck is -!0

[ratsnakegames@mastodon.social]

@joe if you put that in your code, you deserve a compiler error

[rotopenguin@mastodon.social]

@atax1a @joe

[joe@f.duriansoftware.com]

@ratsnakegames not much, what’s -! With you

[regehr@mastodon.social]

@joe "Twenty-minute compile time" is so perfect and understated

[regehr@mastodon.social]

@joe of course with modern OOO processors this would be like 0.2 seconds and would go unnoticed

[cr1901@mastodon.social]

@regehr @joe "Server crash" is doing some work here :D

[regehr@mastodon.social]

@cr1901 @joe it's so good because it implicates the OS as an accomplice

[rotopenguin@mastodon.social]

@regehr @joe good thing it was on the best OO processor of its day, the iAPX432

[rotopenguin@mastodon.social]

@cr1901 singularity (1 million parentheses)

[aburka@hachyderm.io]

@joe "several compiler crashes"

[aburka@hachyderm.io]

@joe crashing multiple times in a single run implies some advanced error handling

[rygorous@mastodon.gamedev.place]

@regehr @joe we had widespread OoO by 1998, John! :P

[tay@transfem.social]

@joe@f.duriansoftware.com okay I'm curious about the original source for this and the reason as to why these happen. Some are obvious but how does if (sizeof(char)+d) f(d) cause an illegal instruction to be emitted?

[rygorous@mastodon.gamedev.place]

@regehr @joe

wild to think how 1989-1999 went from 33MHz pipelined in-order scalar to 500MHz out-of-order superscalar, 1999 to 2004 went to like 3GHz from there, and then 2004 to 2014 was "oh boy, hair shirt time"

[dotstdy@mastodon.social]

@regehr @joe thankfully with modern computers we also have 64 bits so we can now shift by UINT64_MAX

[rygorous@mastodon.gamedev.place]

@regehr @joe or I guess, more accurately, waiting for the cooling people to catch up.

[joe@f.duriansoftware.com]

@tay I put a link to the paper in the alt text: https://www.cs.swarthmore.edu/~bylvisa1/cs97/f13/Papers/DifferentialTestingForSoftware.pdf

[tay@transfem.social]

@joe@f.duriansoftware.com

For example, the server crash occurred when the tested compiler got a stack overflow on a heavily loaded machine with a very large memory. The operating system attempted to dump a gigabyte of compiler stack, which caused all the other active users to thrash, and many of them also dumped for lack of memory. The many disk drives on the server began a dance of the lights that sopped up the remaining free resources, causing the operators to boot the server to recover. Excellent testing can make you unpopular with almost everyone.

[rygorous@mastodon.gamedev.place]

@regehr @joe it's very funny in retrospect to look at the "incredibly power-wasting" Pentium 4 and see that the launch models consumed... like 50W

granted perf/W was definitely way off but still