[all-commits] [llvm/llvm-project] 622f72: [OpenMP] Fix firstprivate pointer handling in targ...

[Sairudra More via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 622f72f4bef8b177e1e4f318465260fbdb7711ef
      https://github.com/llvm/llvm-project/commit/622f72f4bef8b177e1e4f318465260fbdb7711ef
  Author: Sairudra More <sairudra60 at gmail.com>
  Date:   2025-11-21 (Fri, 21 Nov 2025)

  Changed paths:
    M clang/lib/CodeGen/CGOpenMPRuntime.cpp
    M clang/test/OpenMP/target_codegen.cpp
    M clang/test/OpenMP/target_defaultmap_codegen_01.cpp
    M clang/test/OpenMP/target_depend_codegen.cpp
    A clang/test/OpenMP/target_firstprivate_pointer_codegen.cpp
    M clang/test/OpenMP/target_map_codegen_01.cpp
    M clang/test/OpenMP/target_map_codegen_09.cpp
    M clang/test/OpenMP/target_map_codegen_10.cpp
    M clang/test/OpenMP/target_map_codegen_26.cpp
    M clang/test/OpenMP/target_parallel_depend_codegen.cpp
    M clang/test/OpenMP/target_parallel_for_depend_codegen.cpp
    M clang/test/OpenMP/target_parallel_for_simd_depend_codegen.cpp
    M clang/test/OpenMP/target_simd_depend_codegen.cpp
    M clang/test/OpenMP/target_teams_depend_codegen.cpp
    M clang/test/OpenMP/target_teams_distribute_depend_codegen.cpp
    M clang/test/OpenMP/target_teams_distribute_parallel_for_depend_codegen.cpp
    M clang/test/OpenMP/target_teams_distribute_parallel_for_simd_depend_codegen.cpp
    M clang/test/OpenMP/target_teams_distribute_simd_depend_codegen.cpp

  Log Message:
  -----------
  [OpenMP] Fix firstprivate pointer handling in target regions (#167879)

Firstprivate pointers in OpenMP target regions were not being lowered
correctly, causing the runtime to perform unnecessary present table
lookups instead of passing pointer values directly.

This patch adds the OMP_MAP_LITERAL flag for firstprivate pointers,
enabling the runtime to pass pointer values directly without lookups.
The fix handles both explicit firstprivate clauses and implicit
firstprivate semantics from defaultmap clauses.

Key changes:
- Track defaultmap(firstprivate:...) clauses in MappableExprsHandler
- Add isEffectivelyFirstprivate() to check both explicit and implicit
firstprivate semantics
- Apply OMP_MAP_LITERAL flag to firstprivate pointers in
generateDefaultMapInfo()

Map type values:
- 288 = OMP_MAP_TARGET_PARAM | OMP_MAP_LITERAL (explicit firstprivate)
- 800 = OMP_MAP_TARGET_PARAM | OMP_MAP_LITERAL | OMP_MAP_IS_PTR
(implicit firstprivate from defaultmap)

Before: Pointers got 544 (TARGET_PARAM | IS_PTR) causing runtime lookups
After:  Pointers get 288 or 800 (includes LITERAL) for direct pass

Updated the 16 existing test cases in OpenMP that were expecting the
previous (buggy) behavior. The tests were checking for map type values
of 544 (TARGET_PARAM | IS_PTR) and 32 (TARGET_PARAM) for firstprivate
pointers, which lacked the LITERAL flag (256). With this fix,
firstprivate pointers now correctly include the LITERAL flag, resulting
in map types 800 (TARGET_PARAM | LITERAL | IS_PTR) for implicit
firstprivate and 288 (TARGET_PARAM | LITERAL) for explicit firstprivate.
The updated tests now validate the correct behavior as per OpenMP 5.2
semantics, where firstprivate variables should be passed by value rather
than requiring runtime present table lookups.

---------

Co-authored-by: Sairudra More <moresair at pe31.hpc.amslabs.hpecorp.net>
Co-authored-by: Alexey Bataev <a.bataev at gmx.com>



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