[all-commits] [llvm/llvm-project] 74a875: [flang][MLIR][OpenMP] make reduction by-ref toggle...

[Tom Eccles via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 74a87548e5b62881108e6cd1fd63b45580fc3097
      https://github.com/llvm/llvm-project/commit/74a87548e5b62881108e6cd1fd63b45580fc3097
  Author: Tom Eccles <tom.eccles at arm.com>
  Date:   2024-05-16 (Thu, 16 May 2024)

  Changed paths:
    M flang/lib/Lower/OpenMP/ClauseProcessor.cpp
    M flang/lib/Lower/OpenMP/OpenMP.cpp
    M flang/lib/Lower/OpenMP/ReductionProcessor.cpp
    M flang/lib/Lower/OpenMP/ReductionProcessor.h
    M flang/test/Fir/omp-reduction-embox-codegen.fir
    M flang/test/Lower/OpenMP/default-clause-byref.f90
    M flang/test/Lower/OpenMP/delayed-privatization-reduction-byref.f90
    M flang/test/Lower/OpenMP/parallel-reduction-add-byref.f90
    M flang/test/Lower/OpenMP/parallel-reduction-allocatable-array.f90
    M flang/test/Lower/OpenMP/parallel-reduction-array-lb.f90
    M flang/test/Lower/OpenMP/parallel-reduction-array.f90
    M flang/test/Lower/OpenMP/parallel-reduction-array2.f90
    M flang/test/Lower/OpenMP/parallel-reduction-byref.f90
    M flang/test/Lower/OpenMP/parallel-reduction3.f90
    M flang/test/Lower/OpenMP/parallel-wsloop-reduction-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-add-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-add-hlfir-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-allocatable.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-array-assumed-shape.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-array.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-array2.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-iand-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-ieor-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-ior-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-logical-and-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-logical-eqv-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-logical-neqv-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-logical-or-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-max-2-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-max-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-max-hlfir-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-min-byref.f90
    M flang/test/Lower/OpenMP/wsloop-reduction-mul-byref.f90
    A flang/test/Lower/OpenMP/wsloop-reduction-multiple-clauses.f90
    M llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
    M llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
    M llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp
    M mlir/include/mlir/Dialect/OpenMP/OpenMPClauseOperands.h
    M mlir/include/mlir/Dialect/OpenMP/OpenMPOps.td
    M mlir/lib/Conversion/SCFToOpenMP/SCFToOpenMP.cpp
    M mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
    M mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
    M mlir/test/Dialect/OpenMP/invalid.mlir
    M mlir/test/Dialect/OpenMP/ops.mlir
    M mlir/test/Target/LLVMIR/openmp-parallel-reduction-cleanup.mlir
    M mlir/test/Target/LLVMIR/openmp-reduction-byref.mlir
    M mlir/test/Target/LLVMIR/openmp-reduction-init-arg.mlir
    M mlir/test/Target/LLVMIR/openmp-wsloop-reduction-cleanup.mlir

  Log Message:
  -----------
  [flang][MLIR][OpenMP] make reduction by-ref toggled per variable (#92244)

Fixes #88935

Toggling reduction by-ref broke when multiple reduction clauses were
used. Decisions made for the by-ref status for later clauses could then
invalidate decisions for earlier clauses. For example,

```
reduction(+:scalar,scalar2) reduction(+:array)
```

The first clause would choose by value reduction and generate by-value
reduction regions, but then after this the second clause would force
by-ref to support the array argument. But by the time the second clause
is processed, the first clause has already had the wrong kind of
reduction regions generated.

This is solved by toggling whether a variable should be reduced by
reference per variable. In the above example, this allows only `array`
to be reduced by ref.



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