[flang][OpenMP] Fix the use-associated bug in threadprivate directive lowering

[peixin]

Summary

The symbol may be used by use-association for multiple times such
as one in module specification part and one in module procedure.
Then in module procedure, the variable instantiation will be called
for multiple times. But we only need to threadprivatize it once and
use the threadprivatized value for the second time.

Fix #58379.

[peixin]

Think out one better idea to fix this. Doing it.

[kiranchandramohan]

LGTM. Thanks for the quick fix.

flang/lib/Lower/OpenMP.cpp

1778–1780

flang/test/Lower/OpenMP/threadprivate-use-association-2.f90

3

[peixin]

Address the comments.

flang/lib/Lower/OpenMP.cpp

if (Fortran::semantics::IsAllocatableOrPointer(sym)) {
           });
     }
     mlir::Value symValue = firOpBuilder.create<fir::AddrOfOp>(
         currentLocation, global.resultType(), global.getSymbol());
     symThreadprivateValue = firOpBuilder.create<mlir::omp::ThreadprivateOp>(
         currentLocation, symValue.getType(), symValue);
   } else {
     mlir::Value symValue = converter.getSymbolAddress(sym);
+    mlir::Operation *op = symValue.getDefiningOp();
+    // The symbol may be use-associated multiple times, and nothing needs to be
+    // done after the original symbol is mapped to the threadprivatized value
+    // for the first time. Use the threadprivatized value directly.
+    if (mlir::isa<mlir::omp::ThreadprivateOp>(op))
+      return;
     symThreadprivateValue = firOpBuilder.create<mlir::omp::ThreadprivateOp>(
         currentLocation, symValue.getType(), symValue);
   }
 
   fir::ExtendedValue sexv = converter.getSymbolExtendedValue(sym);
   fir::ExtendedValue symThreadprivateExv =
       getExtendedValue(sexv, symThreadprivateValue);
   converter.bindSymbol(sym, symThreadprivateExv);

flang/test/Lower/OpenMP/threadprivate-use-association-2.f90

+! This test checks lowering of OpenMP Threadprivate Directive.
+! Test for threadprivate variable double use in use association.
+
+!RUN: %flang_fc1 -emit-fir -fopenmp %s -o - | FileCheck %s
+!RUN: bbc -emit-fir -fopenmp %s -o - | FileCheck %s
+
+! CHECK-LABEL: fir.global @_QMmEx : i32
+module m
+  integer :: x
+  !$omp threadprivate(x)
+end
+
+! CHECK-LABEL: func.func @_QMm2Ptest() {
+! CHECK:         %[[VAL_0:.*]] = fir.address_of(@_QMmEx) : !fir.ref<i32>
+! CHECK:         %[[VAL_1:.*]] = omp.threadprivate %[[VAL_0]] : !fir.ref<i32> -> !fir.ref<i32>
+! CHECK:         fir.call @_QPbar(%[[VAL_1]]) : (!fir.ref<i32>) -> ()
+! CHECK:         return
+! CHECK:       }
+!
+! CHECK-LABEL: func.func @_QMm2FtestPinternal_test() {
+! CHECK:         %[[VAL_0:.*]] = fir.address_of(@_QMmEx) : !fir.ref<i32>
+! CHECK:         %[[VAL_1:.*]] = omp.threadprivate %[[VAL_0]] : !fir.ref<i32> -> !fir.ref<i32>
+! CHECK:         fir.call @_QPbar(%[[VAL_1]]) : (!fir.ref<i32>) -> ()
+! CHECK:         return
+! CHECK:       }
+
+module m2
+  use m
+ contains
+  subroutine test()
+    use m
+    call bar(x)
+   contains
+    subroutine internal_test()
+      use m
+      call bar(x)
+    end
+  end
+end