http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48052
--- Comment #7 from vincenzo Innocente <vincenzo.innocente at cern dot ch>
2011-03-11 10:16:37 UTC ---
what's the probablity to have this fixed?
We depend on a third party matrix library
that is fully templated and uses everywhere "unsigned int"
I made a test with a
sed -i 's/unsigned int/unsigned long long/g'
and it MAKES a difference (up to a factor 2 in speed).
This modification (although trivial) changes the type of templated vector and
matrix, the signature of functions
and also affects user code.
It is neither transparent nor backward compatible.
I think we cannot afford the change in production: much easier to change
compiler version!
Thanks for any effort dedicated to solve this issue,
Vincenzo
On 10 Mar, 2011, at 12:22 PM, paolo.carlini at oracle dot com wrote:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48052
>
> Paolo Carlini <paolo.carlini at oracle dot com> changed:
>
> What |Removed |Added
> ----------------------------------------------------------------------------
> CC| |paolo.carlini at oracle dot
> | |com
>
> --- Comment #5 from Paolo Carlini <paolo.carlini at oracle dot com>
> 2011-03-10 11:22:26 UTC ---
> Vincenzo, if I understand correctly, maybe Sebastian can also tell us more,
> the
> issue seems that, at some stage, the logic is fully general only assuming the
> widest unsigned type (*), doesn't cope with smaller types. Thus, if my theory
> is correct, unsigned char, unsigned short, etc, all should cause problems. On
> the other hand, on x86_64, unsigned long, unsigned long long, size_t, are all
> the same size, and all work (**)
>
> (*) I don't consider int128, I don't think is relevant for loop optimization.
> (**) On x86, however, unsigned int (aka unsigned long) appears to work, hum.
>
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--
Il est bon de suivre sa pente, pourvu que ce soit en montant.
A.G.
http://www.flickr.com/photos/vin60/1320965757/
