[all-commits] [llvm/llvm-project] c858f4: [flang][OpenMP] Fix firstprivate with barrier

[Shraiysh via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c858f4dbd5d06b227ff87bbe5ebd787d04148749
      https://github.com/llvm/llvm-project/commit/c858f4dbd5d06b227ff87bbe5ebd787d04148749
  Author: Shraiysh Vaishay <Shraiysh.Vaishay at amd.com>
  Date:   2022-06-21 (Tue, 21 Jun 2022)

  Changed paths:
    M flang/lib/Lower/OpenMP.cpp
    M flang/test/Lower/OpenMP/omp-parallel-firstprivate-clause-scalar.f90
    M flang/test/Lower/OpenMP/omp-parallel-wsloop.f90

  Log Message:
  -----------
  [flang][OpenMP] Fix firstprivate with barrier

This patch fixes the unintentional data race in firstprivate
implementation. There is a Read-Write race when one thread tries
to copy the value inside the omp.parallel region while other
thread modifies it from inside the region (using pointers or
some other form of indirect access).

For detailed discussion please refer to [[ https://discourse.llvm.org/t/issues-with-the-current-implementation-of-privatization-in-openmp-with-fortran/62335 | discourse ]].

Reviewed By: kiranchandramohan, peixin, NimishMishra

Differential Revision: https://reviews.llvm.org/D125689