On Wed, Jun 17, 2009 at 11:34 AM, Jeff Law<[email protected]> wrote:
> H.J. Lu wrote:
>> On Wed, Jun 17, 2009 at 11:18 AM, Vladimir Makarov<[email protected]>
>>> I am agree with Jeff and Richard. There is one more reason to avoid
>>> hard registers. Usage of hard registers tends to create more spill
>>> in reload.
>> It is not like you have a choice here. The register for those insns is
>> Sooner or later you have to allocate xmm0 for them.
> And how is that different from any other port that has insns which require
> specific registers for particular insns. This is nothing new or uncommon.
Have you compared generated codes on such insns with and
without early hard register assignment? My observations are
early hard register assignment improves RA on insn with
fixed hard registers: