[llvm] [RegScavenger] Simplify state tracking for backwards scavenging (PR #71202)

[Jay Foad via llvm-commits]

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@@ -1515,11 +1515,6 @@ void PEI::replaceFrameIndicesBackward(MachineBasicBlock *BB,
         break;
     }
 
-    // Refresh the scavenger's internal iterator in case MI was removed or more
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jayfoad wrote:

Nice cleanup here. `LocalRS->MBBI` now points after `MI`, to an instruction which will not have been affected by the call to `TRI.eliminateFrameIndex`, so there is no need to refresh anything.

https://github.com/llvm/llvm-project/pull/71202