On Wed, Apr 30, 2014 at 7:49 PM, Daniel Gutson <daniel.gut...@tallertechnologies.com> wrote: > Hi, > > assuming the need to generate code in which > almost everything is used 3x (e.g. 3x registers, > 3 times data, etc.) for a specific purpose (*) for any > given target, > what would be the best way to implement it? > > (let's name this 3ple-voting behavior) > > a) as a forked backend target of each target (e.g. > a 3ple-voting version of x86, a 3ple-voting version > of ARM, etc.) > > b) as a late GIMPLE phase pluging? > > (*) The need comes from radiation bit-flipping > tolerant software (the interested reader may > check http://en.wikipedia.org/wiki/Single_event_upset). > I am interested in SEUs affecting microprocessor registers > and data. > There is a voting technique in which > the subjects under protection are triplicated, so on each operation, > a check is performed whether the three are equal, or two are equal > (in which case the third is fixed), or the three are distinct. > > Would a late GIMPLE phase plugin suffice? > I think that I should manage to get the RTL tree > with the necessary nodes triplicated and let > the backend do its job, right? Or, am I forgetting > any backend pass that may optimize/get screwed > because of this?
It really depends on how "3x" should materialize in the end. How do you triplicate ops with side-effects? If you only triplicate ops without side-effects what is the sink that keeps the duplicated ops live? Richard. > Thanks! > > Daniel.
