I think we need to reserve an additional register for other uses, like the
smi tag.
I thought it wouldn't hurt to do it now, but I guess we shouldn't  do it
until we have
a definition, like kSmiMaskRegister.  I definitely would use R12, in that
case, since
it is not used in any memory operands.  Removed.

On Fri, Jun 12, 2009 at 11:24 AM, <[email protected]> wrote:

> LGTM
>
>
> http://codereview.chromium.org/126043/diff/1/2
> File src/x64/register-allocator-x64-inl.h (right):
>
> http://codereview.chromium.org/126043/diff/1/2#newcode41
> Line 41: reg.is(kScratchRegister) || reg.is(r12);
> See below for r12.
>
> http://codereview.chromium.org/126043/diff/1/2#newcode49
> Line 49: static int numbers[] = {
> Would it help compiler optimization to make this "const int"?

I don't know.  I hope so.  I'll do it.

>
>
> http://codereview.chromium.org/126043/diff/1/2#newcode62
> Line 62: -1,  // r12
> No need to exclude r12 (unless you reserve it for something yourself).
> We currently disallow r12 as index register, but we shouldn't - it works
> fine. I'll post a CL to remove the restriction.
>
> If anything, if we can make r12 and r13 low priority registers (last in
> line to get used), it might make code a little smaller, since opcodes
> using r13 (with no displacement) or r12 (with no index) as base
> registers cost an extra byte.
>
>
> http://codereview.chromium.org/126043
>



-- 
William Hesse
Software Engineer
[email protected]

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