[Bug middle-end/105640] New: [OpenMP] Context selectors missing for PowerPC

["burnus at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105640

            Bug ID: 105640
           Summary: [OpenMP] Context selectors missing for PowerPC
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Keywords: openmp
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: burnus at gcc dot gnu.org
                CC: jakub at gcc dot gnu.org
  Target Milestone: ---
            Target: powerpc64le,powerpc

Looking at https://gcc.gnu.org/onlinedocs/libgomp/OpenMP-Context-Selectors.html
, I realized that we do now have OpenMP context selectors for PowerPC, which is
somewhat widely used with HPC and offloading and, thus, a relevant omission.

I think something like:
arch = powerpc, powerpc64, powerpc64le, rs64
  ?
kind = cpu
isa = ?
  maybe all values of RS6000_CPU (in rs6000-cpus.def)  excluding or not the
ones from arch
  = documentation wise, -mcpu= w/o 'native' (and possibly the values from arch)

Any other ISA flag?
https://gcc.gnu.org/onlinedocs/gcc/RS_002f6000-and-PowerPC-Options.html

Namely:
* TARGET_OMP_DEVICE_KIND_ARCH_ISA needs to be defined +
   associated rs6000_omp_device_kind_arch_isa be created
* t-omp-device be created
* libgomp.texi updated (cf. link above)
* a test to – or eqiuvalent:
    gcc/testsuite/c-c++-common/gomp/declare-variant-11.c