{"action":"closed","issue":{"url":"https://api.github.com/repos/JuliaLang/julia/issues/12132","labels_url":"https://api.github.com/repos/JuliaLang/julia/issues/12132/labels{/name}","comments_url":"https://api.github.com/repos/JuliaLang/julia/issues/12132/comments","events_url":"https://api.github.com/repos/JuliaLang/julia/issues/12132/events","html_url":"https://github.com/JuliaLang/julia/issues/12132","id":94706287,"number":12132,"title":"Document `jl_zero_subnormals` and also mention denormals in the document","user":{"login":"yuyichao","id":712232,"avatar_url":"https://avatars.githubusercontent.com/u/712232?v=3","gravatar_id":"","url":"https://api.github.com/users/yuyichao","html_url":"https://github.com/yuyichao","followers_url":"https://api.github.com/users/yuyichao/followers","following_url":"https://api.github.com/users/yuyichao/following{/other_user}","gists_url":"https://api.github.com/users/yuyichao/gists{/gist_id}","starred_url":"https://api.github.com/users/yuyichao/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/yuyichao/subscriptions","organizations_url":"https://api.github.com/users/yuyichao/orgs","repos_url":"https://api.github.com/users/yuyichao/repos","events_url":"https://api.github.com/users/yuyichao/events{/privacy}","received_events_url":"https://api.github.com/users/yuyichao/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/JuliaLang/julia/labels/doc","name":"doc","color":"02d7e1"},{"url":"https://api.github.com/repos/JuliaLang/julia/labels/intro%20issue","name":"intro issue","color":"0052cc"}],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":12,"created_at":"2015-07-13T12:11:40Z","updated_at":"2015-07-19T13:06:49Z","closed_at":"2015-07-19T13:06:49Z","body":"Ref: [julia-users](https://groups.google.com/forum/?fromgroups=#!topic/julia-users/KJ3u_2R06vM)\r\n\r\nIt took me a really long time to figure out why there's such a performance difference for exactly the same code but different input. I did check the floating point and performance tip section of the manual but didn't find anything. Would be nice to mention `jl_zero_subnormals` and its performance/accuracy impact in the document.\r\n\r\nIt's also worth noting that `@fastmath` does not have exactly the same effect with `-ffast-math` (at least in this regard). It also took me a long time to figure out why.\r\n\r\nThe document also only mentions subnormals rather than denormals (#3105). I agree the interface should be consistent but it would be nice to mentions both to help searching especially since the [wiki page](https://en.wikipedia.org/wiki/Denormal_number) is still using \"denormal\".\r\n"}}