Weddington, Eric wrote:
-----Original Message----- From:
avr-gcc-list-bounces+eric.weddington=atmel....@nongnu.org
[mailto:avr-gcc-list-bounces+eric.weddington=atmel....@nongnu. org]
On Behalf Of hutchinsona...@aim.com Sent: Friday, August 21, 2009
4:39 PM To: r...@betaresearch.nl; avr-gcc-list@nongnu.org Subject:
Re: [avr-gcc-list] char to int promotion in bitwise operators
Gcc does not permit backends to control optimization pass order.
I don't see any reason why we cannot apply an AVR-specific patch,
post-release to all distributions, that changes the pass order as we
see fit. As long as it works properly for our needs.
Has anyone versed in avr-gcc development looked at the new plugin
architecture in gcc 4.5 ? To my limited understanding, it is (or will
be) possible for a plugin to change the pass order:
<http://gcc.gnu.org/onlinedocs/gccint/Plugins.html>
The hope with the plugins is that it will make it easier and faster to
develop gcc, and it would allow such changes to be done as a plugin
rather than needing open-heart surgery on the gcc pass manager
internals. Surely that would also make it easier to maintain these
changes between gcc versions.
I would hope it is also possible to use plugins to allow extra peephole
optimisations to be written and tested externally to gcc, allowing much
easier and faster testing than rebuilding gcc for each change.
Well-proven peepholes could then be moved back into the main gcc code
for efficiency.
mvh.,
David
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