[flang] [llvm] [AtomicExpand] Let targets keep the release fence out of the reservation (PR #214867)

[via llvm-commits]

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@@ -506,7 +511,8 @@ def ProcessorFeatures {
      FeatureQuadwordAtomic,
      FeaturePredictableSelectIsExpensive,
      FeatureISA2_07,
-     FeatureCRBits
+     FeatureCRBits,
+     FeatureFenceKeepsReservation
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RolandF77 wrote:

Yes, I think this is the right way - but I would like to have it inherited from pwr7 up rather than pwr8 up.

https://github.com/llvm/llvm-project/pull/214867