[llvm-commits] [llvm] r75308 - in /llvm/trunk: include/llvm/CodeGen/ValueTypes.h include/llvm/CodeGen/ValueTypes.td lib/VMCore/ValueTypes.cpp utils/TableGen/CodeGenTarget.cpp

[Chris Lattner]

On Jul 12, 2009, at 12:03 PM, Anton Korobeynikov wrote:

> Hi, Chris
>
>> X86 idiv isn't a big problem, because it is two specific registers,
>> the allocator doesn't need to do anything fancy here.
> Right, but anyway regpairs could save some manual lowering :)

The issue with idiv is that we can't write patterns in .td files that  
have multiple outputs.  I don't think it is related to register pairs.

>
>> Right, just don't declare the regpair regclass as "legal" at isel
>> lowering time.
> Correct, but we currently don't have such functionality. We either
> treat regclass as 'fully legal' or not existent at all. However, this
> is something which can be easily added.

I specifically mean that you should not call "addRegisterClass" with  
the regclass.

-Chris