Re: avr-ada ubuntu cross-compiler build failed

[Brian Drummond <brian_drummond@btconnect.com>]

On Sat, 12 Feb 2011 13:27:37 +0000, Simon Wright <simon@pushface.org> wrote:

>Brian Drummond <brian_drummond@btconnect.com> writes:
>
>> On Fri, 11 Feb 2011 18:16:27 +0000, Simon Wright <simon@pushface.org> wrote:
>>
>>>Brian Drummond <brian_drummond@btconnect.com> writes:
>>>
>>>> My dreams of success were short-lived, though, when someone pointed
>>>> out a catastrophic bug in GCC4.5.0 targeting the AVR...
>>
>>>Actually, this bug is also present in gcc version 4.6.0 20110203
>>>(experimental) [trunk revision 157963] for x86_64-apple-darwin10.
>>>
>>>I've updated bugzilla
>>>(http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46192).
>>>
>>>The problem is there at -O2, goes away at -O1 (and -O0).
>>
>> Do you happen to know if this applies ("goes away at -O1") in GCC4.5 too, or
>> just 4.6?
>>
>> (If so, I may stick with 4.5.0 and -O1 for the time being, until I run out of
>> space)
>
>Yes, it does. (on x86_64-apple-darwin10).

Thanks.

>Are you sure this is really a problem for you? It's that pragma Volatile
>isn't retained *through a renaming*. Do you have to rename?

Good point, there are other ways around the problem. 

However some of the example code uses renaming, and I can see why. Naming a
register or bit according to it's intent, rather than its address, does add a
lot to readability, essentially "for free" in terms of code generation. 

- Brian