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  1. JDK
  2. JDK-8252990

Intrinsify Unsafe.storeStoreFence

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      These Unsafe.storeStoreFence currently delegates to stronger Unsafe.storeFence. We might want to teach C1/C2 to map this directly to matchers that already handle Op_MemBarStoreStore.

      For example:
       https://github.com/openjdk/jdk/compare/master...shipilev:JDK-8252990

      It realistically affects weakly memory ordered machines. But we need to figure out if it is even profitable to do. For example, on modern AArch64 both fences perform pretty much the same:

      Benchmark Mode Cnt Score Error Units
      Fences.releaseFence avgt 3 12.014 ± 0.069 ns/op # "dmb ish"
      Fences.storeStoreFence avgt 3 12.022 ± 0.145 ns/op # "dmb ishst"

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            • Assignee:
              shade Aleksey Shipilev
              Reporter:
              shade Aleksey Shipilev
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              • Created:
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