[llvm-commits] PATCH: remove VICmp and VFCmp.

[Dan Gohman]

On Jul 8, 2009, at 2:03 AM, Duncan Sands wrote:


> Hi Eli,
>
>
>>> I think this is a misunderstanding of the roles of type and
>>>
>>> operation legalization.  The getTypeToTransformTo method exists
>>>
>>> entirely for the benefit of type legalization.  Since <4 x i1> is
>>>
>>> an illegal type, it needs to be transformed into the legal type
>>>
>>> given by getTypeToTransformTo, for example <4 x i8>.
>>>
>>
>>
>> We don't support that kind of promotion at the moment, although I
>>
>> suppose that's an implementation detail rather than a fundamental
>>
>> issue.
>>
>
> exactly.  The fact that this might not actually work right now is
> an implementation problem, not a conceptual problem.

I'm not saying there are fundamental obstacles here, just that there
is more work to be done than just hooking up existing parts. Teaching
type legalization how to promote illegal vectors of i1 to legal vectors
of wider element types and using operand legalization to finish the
work is an interesting idea.

However, I'm also thinking a few steps beyond what's immediately being
sought here.  The removal of v[if]cmp doesn't require this level of
generality.

Dan