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

[Chris Lattner]

On Jul 8, 2009, at 3:09 PM, Dan Gohman wrote:

>>
>> I haven't been tracking this, so can someone explain what the
>> "vectors of
>> i1 problem" is?  Is it a problem of how to generate code on
>> architectures
>> that don't have a mask concept?
>
> Yes. One approach to the problem to require IR producers to know that
> certain targets require comparison results to be sign-extended into
> vectors of larger integer types. This is essentially the solution
> being used today.

I don't think this is related.  The reason that clang generates compare 
+sext is that is how the comparison operators are defined at the C  
level in OpenCL.  It doesn't have anything to do with the capabilities  
of the hardware, it is the semantics of the "vec1 = vec2 < vec3"  
operation at the source level.

-Chris