[llvm-commits] Fixing Bug 13662: paired register for inline asm with 64-bit data on ARM

[Jakob Stoklund Olesen]

On Oct 1, 2012, at 8:40 AM, Jim Grosbach <grosbach at apple.com> wrote:

> Hello,
> 
> I'm a bit confused by the following FIXME from the patch:
> +      // FIXME: When LLVM supports paired register class for 64-bit data in
> +      // future, we should just return that register class here and let register
> +      // allocator to assign physical registers.
> 
> Why not just add such a register class and use it? It seems that would make all of the AssignedPhysRegs handling unnecessary.

I agree, we need a GPRPair register class similar to the DPair class.

The problems caused by SelectionDAG's type system can be worked around by making the register class untyped, like the DTriple class. I agree that i64 should not be a legal type on ARM.

/jakob