v3.1.x: opal/asm: work around possible gcc compiler bug #6042
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It seems in some cases (gcc older than v6.0.0) the __atomic_thread_fence is a no-op with __ATOMIC_ACQUIRE. This appears to be the case with X86_64 so go ahead and use __ATOMIC_SEQ_CST for the x86_64 read memory barrier. This should not cause any performance issues as it is equivalent to the memory barrier in the hand-written atomics. References open-mpi#6014 Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov> (cherry picked from commit 30119ee) Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
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Nov 8, 2018
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It seems in some cases (gcc older than v6.0.0) the __atomic_thread_fence is a
no-op with __ATOMIC_ACQUIRE. This appears to be the case with X86_64 so go
ahead and use __ATOMIC_SEQ_CST for the x86_64 read memory barrier. This should
not cause any performance issues as it is equivalent to the memory barrier
in the hand-written atomics.
References #6014
Signed-off-by: Nathan Hjelm hjelmn@lanl.gov
(cherry picked from commit 30119ee)
Signed-off-by: Nathan Hjelm hjelmn@lanl.gov