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Re: std::norm improvement
- From: Andrew Pinski <pinskia at gmail dot com>
- To: Jaroslav Hajek <highegg at gmail dot com>
- Cc: libstdc++ at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org
- Date: Wed, 4 Mar 2009 00:22:29 -0800
- Subject: Re: std::norm improvement
- References: <69d8d540903032342l70cb7169uefec213cd27b00d0@mail.gmail.com>
" Still, I think
gcc is pointlessly (is that an English word?) decreasing performance
if ffast-math is not on (it's not on even with -O3).
"
No it is not, this is the problem here. That is from the thread you
wrote in. You did not test every single input to figure out if your
implementation is better or worse. I think it might be best if you
tested every input include NaNs and infs. That is where some problems
come into play also I think.
Remember that a NaN input should result in a NaN result.
Thanks,
Andrew Pinski