[llvm-commits] [llvm] r52454 - /llvm/trunk/lib/Target/X86/X86InstrInfo.td

[Chris Lattner]

On Jun 18, 2008, at 10:54 AM, Evan Cheng wrote:

>
> On Jun 18, 2008, at 9:20 AM, Dan Gohman wrote:
>
>> On Wed, June 18, 2008 1:13 am, Evan Cheng wrote:
>>> Author: evancheng
>>> Date: Wed Jun 18 03:13:07 2008
>>> New Revision: 52454
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=52454&view=rev
>>> Log:
>>> XOR32rr, etc. are not AsCheapAsMove, but MOV32ri, etc. are.
>>
>> MOV32ri is 5 bytes of encoding, while MOV32rr is 2 bytes.
>> Is MOV32ri really "as cheap"?
>
> Don't blame me for the name. :-) It's AsFastAsMove.

Cheapness should eventually be predicated on "optimize for size" I  
guess.  However, remember that we're often avoiding spill/restore code  
when we use this, so it will probably be smaller too.

-Chris