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Re: Options of fixing biggest alignment in PR target/38736
"H.J. Lu" <hjl.tools@gmail.com> writes:
> On Wed, Jan 7, 2009 at 2:47 PM, Ian Lance Taylor <iant@google.com> wrote:
>> 2) Introduce __attribute__ ((aligned (max))). This will be documented
>> as having the largest value available for any version of the
>> architecture, and thus in particular it may change if new versions
>> of the architecture are released. The value will not change based
>> on command line options which do not change the ABI; that is, if it
>> is possible to link together two files compiled with different set
>> of command line options and expect the result to work, then those
>> command line options must not change the value of this attribute.
>> The value will be guaranteed to be sufficient to hold any type,
>> including any vector type. The default will be BIGGEST_ALIGNMENT.
>> The value for the x86/x86_64 will (presumably) be 256.
>>
>
> 256 isn't big enough. There are 512bit vectors in the future:
>
> http://en.wikipedia.org/wiki/Larrabee_(GPU)
>
> 1024bit vector isn't impossible either.
Of course a 1024 bit vector need not require 1024 bit alignment. In
any case, we can set it higher now if we want, or we can wait until we
support those processors.
Ian