[llvm] [CodeGen] Combine two loops in SloIndexes.cpp file (PR #127631)

[Matt Arsenault via llvm-commits]

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@@ -220,32 +221,39 @@ void SlotIndexes::repairIndexesInRange(MachineBasicBlock *MBB,
     MachineInstr *SlotMI = ListI->getInstr();
     MachineInstr *MI = (MBBI != MBB->end() && !pastStart) ? &*MBBI : nullptr;
     bool MBBIAtBegin = MBBI == Begin && (!includeStart || pastStart);
+    bool MIIndexNotFound = MI && mi2iMap.find(MI) == mi2iMap.end();
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arsenm wrote:

this can still use contains 

https://github.com/llvm/llvm-project/pull/127631