[cfe-commits] [cfe-dev] [PATCH] Asm multiple alternative constraints revisited

[Eli Friedman]

On Mon, Aug 9, 2010 at 3:02 PM, John Thompson
<john.thompson.jtsoftware at gmail.com> wrote:
> May I have permission to check this in?

The stopgap should really be to cut off the constraints just before
the first comma rather than ignore the comma... otherwise, it would be
possible to end up with very strange errors in the assembler with more
complicated multi-alternative constraint usages.  Would that be much
more difficult?

-Eli

> On Fri, Aug 6, 2010 at 9:28 AM, John Thompson
> <john.thompson.jtsoftware at gmail.com> wrote:
>>
>> Thanks, Eli.
>>
>> Then do I have permission to check in the front end changes, leaving the
>> back end as-is for now, treating any further work there as a separate issue
>> to be discussed first on llvmdev?
>>
>> Basically, without these front-end changes, there will be an assert in the
>> front end code gen (-emit-llvm) if multi-alt constraints are seen, because
>> the extra commas are not expected.
>>
>> -John
>>
>> On Thu, Aug 5, 2010 at 8:14 PM, Eli Friedman <eli.friedman at gmail.com>
>> wrote:
>>>
>>> On Thu, Aug 5, 2010 at 7:54 PM, John Thompson
>>> <john.thompson.jtsoftware at gmail.com> wrote:
>>> > Eli,
>>> >
>>> > So, then this is a problem with the back-end, right?  Do you agree that
>>> > the
>>> > back end is a better place to try to choose constraints, given that it
>>> > knows
>>> > better which things are already in registers and so forth?
>>>
>>> Yes, it would fit more naturally there... but I'm not sure a proposal
>>> to make inline asm in the backend more complicated will be greeted
>>> with much enthusiasm.  If you're really interested in pursuing that
>>> path, though, ask on llvmdev first.
>>>
>>> -Eli
>>
>>
>>
>> --
>> John Thompson
>> John.Thompson.JTSoftware at gmail.com
>>
>
>
>
> --
> John Thompson
> John.Thompson.JTSoftware at gmail.com
>
>
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