[llvm-dev] MachineCSE ignores COPY

[Quentin Colombet via llvm-dev]

Hi Vivek,

My guess is because copies are transient, so we expect them to disappear anyway.

Maybe it has to do as well with the fact that chances are the are dealing with physical reg copies, e.g., used for ABI.

Cheers,
-Quentin

> On Oct 18, 2020, at 11:07 PM, vivek pandya via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> Hello,
> 
> I see that MachienCSE ignores COPY instructions 
> bool MachineCSE::isCSECandidate(MachineInstr *MI) {
> ...
>   // Ignore copies.
>   if (MI->isCopyLike())
>     return false;
> 
> Are there any correctness concerns?
> 
> Thanks,
> Vivek
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