[llvm] [MachineScheduler][NFCI] Add Offset and OffsetIsScalable args to shouldClusterMemOps (PR #73778)

[Alex Bradbury via llvm-commits]

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@@ -1496,12 +1496,18 @@ class TargetInstrInfo : public MCInstrInfo {
   /// to TargetPassConfig::createMachineScheduler() to have an effect.
   ///
   /// \p BaseOps1 and \p BaseOps2 are memory operands of two memory operations.
+  /// \p Offset1 and \p Offset2 are the byte offsets for the memory
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asb wrote:

Looking at ElementCount, I'm not sure it's semantically the right abstraction? e.g. for `LW %0:gpr, 12` we'd be passing `Offset1=12` and `OffsetIsScalable1=false`. `ElementCount` doesn't seem right for representing that.

https://github.com/llvm/llvm-project/pull/73778