[flang] [llvm] [flang][OpenMP] Overhaul implementation of ATOMIC construct (PR #137852)

[Krzysztof Parzyszek via llvm-commits]

kparzysz wrote:

I ran the Fujitsu test suite with main (`dec8f1314fbf`) and with my branch ('1cd625322638') + patch to allow elements of allocatable arrays.  The top of the main branch is the one that's merged in the atomic branch.

There were no failures introduced in the run using the atomic branch, moreover the following tests that failed with the main branch, now passed:

Fujitsu/Fortran/0352/Fujitsu-Fortran-0352_0059.test
Fujitsu/Fortran/0407/Fujitsu-Fortran-0407_0008.test
Fujitsu/Fortran/0407/Fujitsu-Fortran-0407_0012.test
Fujitsu/Fortran/0407/Fujitsu-Fortran-0407_0013.test
Fujitsu/Fortran/0407/Fujitsu-Fortran-0407_0014.test
Fujitsu/Fortran/0407/Fujitsu-Fortran-0407_0027.test
Fujitsu/Fortran/0407/Fujitsu-Fortran-0407_0028.test
Fujitsu/Fortran/0407/Fujitsu-Fortran-0407_0029.test
Fujitsu/Fortran/0407/Fujitsu-Fortran-0407_0034.test
Fujitsu/Fortran/0481/Fujitsu-Fortran-0481_0004.test
Fujitsu/Fortran/0481/Fujitsu-Fortran-0481_0006.test
Fujitsu/Fortran/0481/Fujitsu-Fortran-0481_0027.test
Fujitsu/Fortran/0481/Fujitsu-Fortran-0481_0028.test
Fujitsu/Fortran/0481/Fujitsu-Fortran-0481_0029.test
Fujitsu/Fortran/0481/Fujitsu-Fortran-0481_0030.test
Fujitsu/Fortran/0481/Fujitsu-Fortran-0481_0031.test
Fujitsu/Fortran/0481/Fujitsu-Fortran-0481_0038.test


https://github.com/llvm/llvm-project/pull/137852