Unverified Commit 8116e869 authored by CHANDRA GHALE's avatar CHANDRA GHALE Committed by GitHub
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[Flang][OpenMP] Fix crash lowering parallel do with nested tile construct (#193955) 

This fixes a crash in OpenMP lowering for cases like `!$omp parallel do
with nested !$omp tile sizes(...)` .
The loop-walk logic now correctly steps through intermediate OpenMP
transformation wrappers to find the actual do construct, instead of
assuming it is directly nested.

Fixes :
[https://github.com/llvm/llvm-project/issues/193256](https://github.com/llvm/llvm-project/issues/193256)
sample reproducer :
[https://godbolt.org/z/b7zecYEMT](https://godbolt.org/z/b7zecYEMT)



Co-authored-by: default avatarChandra Ghale <ghale@pe34genoa.hpc.amslabs.hpecorp.net>
parent 889708ee

flang/lib/Lower/OpenMP/Utils.cpp

+7 −3
Original line number Diff line number Diff line
@@ -702,9 +702,13 @@ pft::Evaluation *getNestedDoConstruct(pft::Evaluation &eval) { 
    //     <<DoConstruct>> -> 7

    if (nested.getIf<parser::NonLabelDoStmt>())

      continue;

    assert(nested.getIf<parser::DoConstruct>() &&

           "Unexpected construct in the nested evaluations");

    if (nested.getIf<parser::DoConstruct>())

      return &nested;

    // Loop transformations can introduce nested OpenMP

    // constructs between the directive and the actual do-loop nest.

    if (nested.getIf<parser::OpenMPConstruct>())

      return getNestedDoConstruct(nested);

    assert(false && "Unexpected construct in the nested evaluations");

  }

  llvm_unreachable("Expected do loop to be in the nested evaluations");

}

flang/test/Lower/OpenMP/tile-parallel-do.f90

0 → 100644
+22 −0
Original line number Diff line number Diff line 
! RUN: %flang_fc1 -emit-hlfir -fopenmp -fopenmp-version=51 -o - %s | FileCheck %s



subroutine func7(a)

  implicit none

  double precision :: a(100, 100)

  integer :: i, j



  !$omp parallel do

  !$omp tile sizes(4, 16)

  do i = 1, 100

    do j = 1, 100

      a(j, i) = a(j, i) + 1.0d0

    end do

  end do

end subroutine



! CHECK-LABEL: func.func @_QPfunc7(

! CHECK: omp.parallel

! CHECK: omp.wsloop

! CHECK: omp.loop_nest

! CHECK-SAME: tiles(4, 16)