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Re: gcc -march=nocona -mtune=nocona --help=target
Alexander Monakov <amonakov@ispras.ru> writes:
> On Wed, Apr 22, 2009 at 06:30:39AM -0700, Ian Lance Taylor wrote:
>> Oleg Kravchenko <oleg@kaa.org.ua> writes:
>>
>> > Why gcc say what mmx, sse, sse2 is disabled?
>> >
>> > $ gcc -march=nocona -mtune=nocona --help=target
>>
>> They are disabled because you didn't explicitly request them.
>>
>> Ian
>
> Sorry, Ian, but is this behaviour really intended? These extensions are
> enabled by gcc/config/i386/i386.c:override_options() for -march=nocona, and if
> one uses -fverbose-asm, they are really listed as enabled there. IMHO, in
> this situation behaviour of -Q --help=target and -fverbose-asm seems
> contradictory and a bit confusing to the user.
>
> Perhaps GCC could do better by calling OVERRIDE_OPTIONS (currently in
> toplev.c:process_options()) before calling decode_options()? Is it worth a
> bugzilla entry?
As I see it, --help=target reports the state of the command line
options. I agree that this behaviour can be confusing, but I also think
it would be difficult to fix in a consistent way across targets. But,
yes, I think this would be worth an enhancement request in bugzilla to
avoid user confusion. Thanks.
Ian