[llvm-commits] [PATCH (try 4)] Add an atomic lowering pass

[Daniel Dunbar]

Hi Peter,

Patch looks good to me, thanks!

 - Daniel

On Tue, Aug 3, 2010 at 6:01 AM, Peter Collingbourne <peter at pcc.me.uk> wrote:
> Ping...
>
> On Sun, Jul 11, 2010 at 04:52:11PM +0100, Peter Collingbourne wrote:
>> 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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