subreg against register allocation?

[Bernd Schmidt]

On 06/14/2010 07:58 PM, Ian Lance Taylor wrote:
> "Amker.Cheng" <amker.cheng@gmail.com> writes:
> 
>> Wondering whether possible to handle multi-word mode with more accuracy,
>> in either subreg or IRA pass?
> 
> Yes, it is possible.  What you need to do is to write a split which
> turns the mult:DI insn into an insn which sets two separate subregs.

Is it valid to have an insn set two different subregs of the same pseudo
in parallel?  I have the same problem on ARM, but I couldn't convince
myself that writing such a split was safe so I'm currently trying to
solve the problem in the register allocator.


Bernd