[llvm-commits] [PATCH (try 3)] Add an atomic lowering pass

[Peter Collingbourne]

Hi,

Ping...

I also updated the patch (attached) to add an entry in docs/Passes.html
for the pass.

Thanks,

On Wed, Jun 30, 2010 at 02:42:11PM +0100, Peter Collingbourne wrote:
> Hi,
> 
> Here is the new version of the patch.  I updated it to use
> getArgOperand and fixed a coding style issue (header ordering).
> 
> Thanks,
> 
> On Thu, Jun 24, 2010 at 12:32:42AM +0100, Peter Collingbourne wrote:
> > Hi Duncan,
> > 
> > On Wed, Jun 23, 2010 at 09:25:39AM +0200, Duncan Sands wrote:
> > > Hi Peter,
> > > 
> > > > My main motivation for the single-thread lowering is to be able to run
> > > > code that uses these intrinsics in the KLEE symbolic execution engine
> > > > but I imagine it could have other uses such as a whole-program LTO
> > > > that lowers atomic operations to more efficient non-atomic operations
> > > > when it is known to be safe to do so.
> > > 
> > > instead, how about writing an LLVM IR pass that turns atomic intrinsics into
> > > non-atomic equivalent LLVM IR?
> > 
> > Yes, that seems more sensible.  I refactored the lowering into a pass
> > and added the remaining intrinsics (see attached patch).  I'll commit
> > this if approved.
> > 
> > I wonder if IntrinsicLowering should also be made into a pass, for
> > consistency with the other lowering passes.
> > 
> > > Finally, I guess even "single threaded" code
> > > may have a use for some atomic operations if it makes use of signal handlers.
> > 
> > Yes, good point.  Perhaps "non-preemptible" is better terminology
> > which is what I used in the new patch.
-- 
Peter
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