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-rw-r--r--tools/memory-model/litmus-tests/ISA2+pooncerelease+poacquirerelease+poacquireonce.litmus39
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diff --git a/tools/memory-model/litmus-tests/ISA2+pooncerelease+poacquirerelease+poacquireonce.litmus b/tools/memory-model/litmus-tests/ISA2+pooncerelease+poacquirerelease+poacquireonce.litmus
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+++ b/tools/memory-model/litmus-tests/ISA2+pooncerelease+poacquirerelease+poacquireonce.litmus
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+C ISA2+pooncerelease+poacquirerelease+poacquireonce
+
+(*
+ * Result: Never
+ *
+ * This litmus test demonstrates that a release-acquire chain suffices
+ * to order P0()'s initial write against P2()'s final read. The reason
+ * that the release-acquire chain suffices is because in all but one
+ * case (P2() to P0()), each process reads from the preceding process's
+ * write. In memory-model-speak, there is only one non-reads-from
+ * (AKA non-rf) link, so release-acquire is all that is needed.
+ *)
+
+{}
+
+P0(int *x, int *y)
+{
+ WRITE_ONCE(*x, 1);
+ smp_store_release(y, 1);
+}
+
+P1(int *y, int *z)
+{
+ int r0;
+
+ r0 = smp_load_acquire(y);
+ smp_store_release(z, 1);
+}
+
+P2(int *x, int *z)
+{
+ int r0;
+ int r1;
+
+ r0 = smp_load_acquire(z);
+ r1 = READ_ONCE(*x);
+}
+
+exists (1:r0=1 /\ 2:r0=1 /\ 2:r1=0)