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Re: [COMMITTED] tilegx: enable wordsize-64 support for ieee745 dbl-64.
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Chris Metcalf <cmetcalf at ezchip dot com>
- Cc: Andrew Pinski <pinskia at gmail dot com>, Joseph Myers <joseph at codesourcery dot com>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Fri, 26 Dec 2014 07:44:48 -0800
- Subject: Re: [COMMITTED] tilegx: enable wordsize-64 support for ieee745 dbl-64.
- Authentication-results: sourceware.org; auth=none
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On Fri, Dec 26, 2014 at 7:06 AM, Chris Metcalf <firstname.lastname@example.org> wrote:
> On 12/24/2014 6:45 PM, Andrew Pinski wrote:
>> On Wed, Dec 24, 2014 at 9:10 AM, Chris Metcalf <email@example.com>
>>> 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
>> 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.