[llvm] TargetSchedule: factor out code in computeOperandLatency (NFC) (PR #73769)

[Francesco Petrogalli via llvm-commits]

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@@ -186,21 +189,16 @@ unsigned TargetSchedModel::computeOperandLatency(
       unsigned DefClass = DefMI->getDesc().getSchedClass();
       OperLatency = InstrItins.getOperandCycle(DefClass, DefOperIdx);
     }
-    if (OperLatency >= 0)
-      return OperLatency;
-
-    // No operand latency was found.
-    unsigned InstrLatency = TII->getInstrLatency(&InstrItins, *DefMI);
 
     // Expected latency is the max of the stage latency and itinerary props.
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fpetrogalli wrote:

Maybe update this comment? Nobody is calling "a TTI hook" at this point, it was done before.

https://github.com/llvm/llvm-project/pull/73769