[LLVMdev] Proposal for atomic and synchronization instructions

[Chandler Carruth]

Hello,

After a fair amount of research and work, I have put together a
concrete proposal for LLVM representations of atomic operations and
synchronization constructs. These aim to provide the minimal
functionality in the IR for representing the hardware constructs that
threading libraries and parallel programming rely on.

http://chandlerc.net/llvm_atomics.html

While I am no expert on the various architectures, I've done my best
at providing base-line implementations for each instruction. I am sure
these will need tweaking and fixing, but should provide a very good
starting point for the targets.

Comments are more than welcome, especially suggestions for
improvement. I hope this provides a sound background and a good
starting place for bringing these features to LLVM. Many thanks also
go to Reid who has helped tremendously with putting this together, and
several of the people at Aerospace who helped in the research phase.

-Chandler Carruth