[LLVMdev] NO-OP

[Evan Cheng]

On Jul 13, 2007, at 11:43 AM, Fernando Magno Quintao Pereira wrote:

>
>> Why do you want to do this?  Empty MBBs are valid, and it's probably
>> better to have your code handle them.
>
> Currently, that is the solution. I have a special treatment for empty
> basic blocks. I think the code would be more homogeneous if there  
> were no
> empty basic blocks.
>
>>
>> There is a NOP "instruction" on x86, equivalent to XCHG EAX, EAX.
>
> The problem with xchk EAX, EAX is that is uses registers, and it would
> add a small burden on the register allocator.

It won't. EAX is not an explicit operand. The register allocator  
doesn't need to know it touches any register.

Evan


>
> Fernando
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