[flang][OpenMP] failure in lowering `taskgroup` construct with `allocate` to llvm-ir

[SouraVX]

Reproducer:

subroutine omp_taskgroup
use omp_lib
integer :: allocated_x
!$omp taskgroup allocate(omp_high_bw_mem_alloc: allocated_x)
!$omp task
   call work()
!$omp end task
end subroutine

Err Log:

$ bbc taskgroup.f90 -o -|tco
Relevant pieces of Err:
loc("taskgroup.mlir":4:3): error: null operand found
"llvm.func"() ({
  %0 = "llvm.mlir.constant"() {value = 1 : i32} : () -> i32
  %1 = "llvm.mlir.constant"() {value = 1 : i64} : () -> i64
  %2 = "llvm.alloca"(%1) {bindc_name = "allocated_x", in_type = i32, operand_segment_sizes = array<i32: 0, 0>, uniq_name = "_QFomp_taskgroupEallocated_x"} : (i64) -> !llvm.ptr<i32>
  "omp.taskgroup"(<<NULL VALUE>>, %0) ({
    "omp.task"() ({
      "llvm.call"() {callee = @_QPwork, fastmathFlags = #llvm.fastmath<>} : () -> ()
      "omp.terminator"() : () -> ()
    }) {operand_segment_sizes = array<i32: 0, 0, 0, 0, 0, 0>} : () -> ()
    "omp.terminator"() : () -> ()
  }) {operand_segment_sizes = array<i32: 0, 1, 1>} : (<<NULL TYPE>>, i32) -> ()
  "llvm.return"() : () -> ()
}) {CConv = #llvm.cconv<ccc>, function_type = !llvm.func<void ()>, linkage = #llvm.linkage<external>, sym_name = "_QPomp_taskgroup"} : () -> ()

[llvmbot]

@llvm/issue-subscribers-openmp

[llvmbot]

@llvm/issue-subscribers-flang-ir

[PeixinQiao]

@SouraVX I think the root cause is there is no conversion for taskgroup operation from OpenMP Op in FIR side to OpenMP Op in MLIR side. The code is here. You can refer to @kiranchandramohan 's previous patch for Critical construct https://reviews.llvm.org/D130343.

[llvmbot]

@llvm/issue-subscribers-bug