[Openmp-commits] [PATCH] D46842: [OpenMP][libomptarget] Make bitcode library building depend on clang and llvm-linker being available

[Hal Finkel via Phabricator via Openmp-commits]

hfinkel added a comment.

In https://reviews.llvm.org/D46842#1104154, @guansong wrote:

> In https://reviews.llvm.org/D46842#1100723, @Hahnfeld wrote:
>
> > In https://reviews.llvm.org/D46842#1099392, @guansong wrote:
> >
> > > Can we double check this LLVM IR backward compatible thing? My understanding is that it is not that good, at least for the major versions.
> >
> >
> >
> >
> > In https://reviews.llvm.org/D46842#1099415, @guansong wrote:
> >
> > > I just want to comment this last point, my understanding is that it will not work even you try to inline older LLVM IR into a newer one.
> >
> >
> > I did just that: I built libomptarget-nvptx-bc with Clang 3.9.1 (which is actually the only released version that you can currently build with) and inlined the result with LLVM/Clang trunk which will become 7.0. It worked without problems for all simple test cases I tried. Do you have a scenario that fails for you?
>
>
> My understanding is that if things like the data layout is changed between versions, the old code will simply be wrong from the new version's perspective.


That's correct. If you change the data layout then you can't, in general, combine the IR with other IR with a different data layout in one module.


Repository:
  rOMP OpenMP

https://reviews.llvm.org/D46842