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|---|---|
| From | christian.bau@cbau.wanadoo.co.uk |
| Newsgroups | comp.compilers |
| Subject | Re: Compiler optimization and floating point operations |
| Date | Mon, 28 Oct 2013 15:54:46 -0700 (PDT) |
| Organization | Compilers Central |
| Lines | 18 |
| Sender | johnl@iecc.com |
| Approved | comp.compilers@iecc.com |
| Message-ID | <13-10-038@comp.compilers> (permalink) |
| References | <13-10-026@comp.compilers> <13-10-029@comp.compilers> <13-10-032@comp.compilers> |
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| X-Trace | leila.iecc.com 1383014812 23217 64.57.183.58 (29 Oct 2013 02:46:52 GMT) |
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| NNTP-Posting-Date | Tue, 29 Oct 2013 02:46:52 +0000 (UTC) |
| Keywords | optimize |
| Posted-Date | 28 Oct 2013 22:46:52 EDT |
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| Xref | csiph.com comp.compilers:1021 |
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On Thursday, October 24, 2013 5:38:13 PM UTC+1, Steven G. Kargl wrote:
> #include <stdio.h>
> int
> main(void)
> {
> float a, b;
> a = 0.;
> b = a / a;
> if (a + b != b + a) printf("fubar\n");
> return (0);
> }
>
> Can an optimizing compiler eliminate the if-statement?
It can eliminate the test because it will always be true (on IEEE
implementations where 0.0 / 0.0 is NaN). It cannot eliminate the
if-statement because printf () should be called.
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Compiler optimization and floating point operations Abid <abidmuslim@gmail.com> - 2013-10-23 13:47 -0700
Re: Compiler optimization and floating point operations Cameron McInally <cameron.mcinally@nyu.edu> - 2013-10-23 22:55 -0400
Re: Compiler optimization and floating point operations glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-10-24 02:56 +0000
Re: Compiler optimization and floating point operations George Neuner <gneuner2@comcast.net> - 2013-10-24 07:41 -0400
Re: Compiler optimization and floating point operations Jean-Marc Bourguet <jm@bourguet.org> - 2013-10-24 15:51 +0200
Re: Compiler optimization and floating point operations "Steven G. Kargl" <sgk@troutmask.apl.washington.edu> - 2013-10-24 16:38 +0000
Re: Compiler optimization and floating point operations christian.bau@cbau.wanadoo.co.uk - 2013-10-28 15:54 -0700
Re: Compiler optimization and floating point operations George Neuner <gneuner2@comcast.net> - 2013-10-24 15:51 -0400
Re: Compiler optimization and floating point operations glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-10-24 20:21 +0000
Re: Compiler optimization and floating point operations christian.bau@cbau.wanadoo.co.uk - 2013-10-28 15:50 -0700
Re: Compiler optimization and floating point operations Cameron McInally <cameron.mcinally@nyu.edu> - 2013-10-28 20:41 -0400
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