[flang] [llvm] [flang][OpenMP] Add parsing support for Task detach (PR #112312)

[Leandro Lupori via llvm-commits]

================
@@ -0,0 +1,16 @@
+! RUN: %flang_fc1 -fdebug-dump-parse-tree -fopenmp -fopenmp-version=50  %s | FileCheck --ignore-case %s
+! RUN: %flang_fc1 -fdebug-unparse -fopenmp -fopenmp-version=50  %s | FileCheck --ignore-case --check-prefix="CHECK-UNPARSE" %s
+
+!CHECK: OmpBlockDirective -> llvm::omp::Directive = task
+!CHECK: OmpClauseList -> OmpClause -> Detach -> OmpDetachClause -> OmpObject -> Designator -> DataRef -> Name = 'event'
+
+!CHECK-UNPARSE: INTEGER(KIND=8_4) event
+!CHECK-UNPARSE: !$OMP TASK  DETACH(event)
+!CHECK-UNPARSE: !$OMP END TASK
+subroutine task_detach
+  use omp_lib
----------------
luporl wrote:

`use omp_lib` needs `! REQUIRES: openmp_runtime`, to avoid errors when OpenMP runtime is not available.

https://github.com/llvm/llvm-project/pull/112312