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Re: What is acceptable for -ffast-math? A numerical viewpoint
- To: dewar at gnat dot com
- Subject: Re: What is acceptable for -ffast-math? A numerical viewpoint
- From: Laurent Guerby <guerby at acm dot org>
- Date: Sun, 5 Aug 2001 14:42:04 +0200
- CC: jthorn at galileo dot thp dot univie dot ac dot at, gcc at gcc dot gnu dot org, guerby at acm dot org
- References: <20010805105124.38520F2B53@nile.gnat.com>
- Reply-to: guerby at acm dot org
<<
The point is that the rules have to be coherent and well documented and
understood. You are NOT going to achieve that unless you have input from
people who understand :-)
>>
I was merely proposing to have a flag (one of the name I proposed
was -funsafe-fast-math) where the rules would be:
1. anyone can go ahead, code and document an optimization
2. volunteers field test it and report on performance and precision
3. unless 2 showed up unfixable practical problems, the optimization
is enabled under -funsafe-fast-math
Do you actively oppose to this proposal?
I have no opinion on other flags, since I do not consider myself an
expert. (My only feeling is that no GCC FP optimization work will be
done at all since all proposals will be discussed endlessly - even
with a "clear set of criteria", whatever that means - and there will
always someone to show up with something that will be badly broken by
the optimization.)
--
Laurent Guerby <guerby@acm.org>