Merge r318848 into the 5.0 branch: Fix for OMP doacross implementation on Power

[hahnjo]

Bugzilla Link	35388
Resolution	FIXED
Resolved on	Nov 27, 2017 09:35
Version	unspecified
OS	All
Blocks	#33840
CC	@AndreyChurbanov,@tstellar
Fixed by commit(s)	r318848 r319057

Extended Description

Power has a weak consistency model so we need memory barriers to
make writes (both from runtime and from user code) available for
all threads.

https://reviews.llvm.org/rL318848

[hahnjo]

assigned to @tstellar

[hahnjo]

I know we are pretty late in the cycle but this commit would be needed for correctness on architectures with a weak memory model (at least Power, probably also ARM).

@​Andrey: Is this ok to merge?

[AndreyChurbanov]

It is OK to merge.

Did I correctly re-assigned the bug?

Thanks.

[tstellar]

Merged: r319057