Re: 2.6.22-rc2 built on ppc

[Stefan Richter <stefanr@s5r6.in-berlin.de>]

Segher Boessenkool wrote:
>>> I don't know what's to blame for the warnings --- new gcc versions or
>>> the change from do { } while (0) to ((void)0)?  Either way, the compiler
>>> should comprehend that the arguments stuffed into the dma_unmap_single
>>> macro are _not_ unused by accident; it should stay quiet and optimize
>>> the unused variables away if run with -Osomething.
>>
>> There is not much that the compiler can do by itself, since the macro
>> expansion happens in the preprocessor.
> 
> Even if the compiler could see that the variables are
> used as macro arguments, this doesn't automatically
> equate to it being able to infer the variables are
> unused on purpose.

Strange.  I believe we had code before with variables that were only
used in macros that expanded to <nil>, notably debug logging macros
which were usually configured out.  Perhaps I'm mistaken.
-- 
Stefan Richter
-=====-=-=== -=-= =-=--
http://arcgraph.de/sr/