[LLVMdev] NO-OP

[Fernando Magno Quintao Pereira]

>> I've built a pass to split critical edges of machine functions, and I have
>> to insert new basic blocks. Some of them will have MBB->begin() ==
>> MBB->end().
>
> Ah, machine basic blocks are different.  They *are* allowed to be empty.
>

I would like to build an "insertNoOp" and add it to MRegisterInfo. I would 
have one for each target. For the x86 I am moving the stack pointer to 
itself. Is there a better "no-op"? A better one would be one that does not 
use any register, so it will add absolutely no burden on the register 
allocator.

Fernando