[PATCH] Modify the register scavenger to operate on reg units when checking liveness

Jakob Stoklund Olesen jolesen at apple.com
Thu Jul 31 14:35:12 PDT 2014


> On Jul 31, 2014, at 2:29 PM, Chad Rosier <mcrosier at codeaurora.org> wrote:
> 
>> 
>> -    // Create callee-saved registers bitvector.
>> +    // Create callee-saved registers bitvector. (FIXME: Why is this
>> needed?)
> 
> I believe the callee-saved register is an ancient artifact.
> 
> Jakob simplified the FindUnusedReg function here:
> http://llvm.org/viewvc/llvm-project?view=revision&revision=79369
> 
> AFAICK, this should have been removed at that time.

Wow, that’s a long time ago, I don’t remember the details.

But it should be trivial to determine if the CSR bitvector is used for anything and delete it if it is unused.

Thanks,
/jakob





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