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Re: [COMMITTED] tilegx: enable wordsize-64 support for ieee745 dbl-64.


On Fri, Dec 26, 2014 at 7:06 AM, Chris Metcalf <cmetcalf@ezchip.com> wrote:
> On 12/24/2014 6:45 PM, Andrew Pinski wrote:
>>
>> On Wed, Dec 24, 2014 at 9:10 AM, Chris Metcalf <cmetcalf@ezchip.com>
>> wrote:
>>>
>>> On 12/23/2014 5:39 PM, H.J. Lu wrote:
>>>>
>>>> You can provide a safe default and let x32 override it.
>>>
>>>
>>> I think it's conventional now to require that platforms are explicit
>>> about #defines, and use #if with -Wundef.  It seems to make good sense
>>> in this case, since it's really not clear what the right default for
>>> any given platform is.
>>>
>>> And since there are currently just two platforms that use wordsize-64
>>> and are !_LP64 (x32 and tilegx32), it feels pretty reasonable to be
>>> explicit for both.  The AArch64 guys will need to set the right default
>>> for their ILP32 mode; I'm not even sure what the right answer is for
>>> them.
>>
>> AARCH64:ILP32 is fine with having the upper bits being undefined when
>> dealing with passing and return values.
>
>
> So sounds like two in each "camp", x32 and AArch64:ILP32 not wanting a cast,
> and tilegx32 and MIPS needing the explicit cast, so requiring a
> preprocessor symbol to be defined for that code seems like the right thing.
>
> Any objections to the proposed code to do the extension in llround.c?
>

Can we find a better name that USE_32BIT_NORMALIZE? How
about REGISTER_CAST_INT32_TO_INT64?  Also it should be an
error if the macro is undefined.

-- 
H.J.


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