[PATCH] D37356: LiveIntervalAnalysis: Fix alias regunit reserved definition

[Matthias Braun via Phabricator via llvm-commits]

MatzeB added inline comments.


================
Comment at: lib/CodeGen/LiveIntervalAnalysis.cpp:279
       if (!MRI->reg_empty(Reg))
         LRCalc->createDeadDefs(LR, Reg);
       // A register unit is considered reserved if all its roots and all their
----------------
kparzysz wrote:
> Should this still happen if Reg is reserved?  For reserved units, the LR will only have dead defs.  Is that the intent?
The code in `RegisterCoalescer::joinReservedPhysReg()` expects it that way. The comment there reads:
```
  // The live range of the reserved register will look like a set of dead defs
  // - we don't properly track the live range of reserved registers.
```


Repository:
  rL LLVM

https://reviews.llvm.org/D37356