[llvm-dev] RFC: LoopIDs are not identifiers (and better loop-parallel metadata)

Michael Kruse via llvm-dev
2018-12-12T16:29:06Z

Am Mi., 12. Dez. 2018 um 10:10 Uhr schrieb Finkel, Hal J. <hfinkel at
anl.gov>:
> > As we have seen,
> > there are other reasons for loops to have identical LoopIDs. With
> > patches [3,4], llvm.loop metadata can be collapsed (unlike access
> > groups), thus the 'distinct' is not necessary anymore.
Unfortunately,
> > there is code in LLVM (and maybe elsewhere) that depends on
LoopIDs'
> > first item, i.e. we cannot get rid of it that easily.
>
> I don't think it's worth changing this first element, unless we
have
> some other reason to do so.

Would it be worthwhile to update the metadata uniquing algorithm to
consider shallow self-references?

Michael