[PATCH] D71170: [PowerPC] [NFC] Cleanup xxpermdi peephole optimization

[Jinsong Ji via Phabricator via llvm-commits]

jsji added inline comments.


================
Comment at: llvm/lib/Target/PowerPC/PPCMIPeephole.cpp:350
+
+        if (TrueReg1 != TrueReg2 || Register::isPhysicalRegister(TrueReg1))
+          break;
----------------
vddvss wrote:
> jsji wrote:
> >  Looks like this might have a problem with `Stack slots`? We used to only handle virtual registers,
> > but now, we might also let throughg stack slots (and Not a register), which might cause build break?
> > 
> > ``` 
> >   //   0           Not a register, can be used as a sentinel.
> >   //   [1;2^30)    Physical registers assigned by TableGen.
> >   //   [2^30;2^31) Stack slots. (Rarely used.)
> >   //   [2^31;2^32) Virtual registers assigned by MachineRegisterInfo.```
> Oh, I didn't know about that. I had used `isPhysicalRegister` based on the pattern in D69497. Should I change this or both of them to `!isVirtualRegister`?
I think so, it is the simplest NFC change. Or else you should go through following code to double check, may sure it won't break anything.


Repository:
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  https://reviews.llvm.org/D71170/new/

https://reviews.llvm.org/D71170