[llvm] [RISCV] add load/store misched/PostRA subtarget features (PR #149409)

[Mikhail Gudim via llvm-commits]

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@@ -1700,6 +1700,18 @@ def TuneNLogNVRGather
 def TunePostRAScheduler : SubtargetFeature<"use-postra-scheduler",
     "UsePostRAScheduler", "true", "Schedule again after register allocation">;
 
+def TuneDisableMISchedLoadClustering : SubtargetFeature<"disable-misched-load-clustering",
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mgudim wrote:

I think @topperc meant to mimic something like "bool RISCVSubtarget::useAA()" for example

https://github.com/llvm/llvm-project/pull/149409