[Flang][OpenMP] Skip default privatization of implied do indices (#89915)

The scope of these indices is limited to the implied-do and is mapped to
SSA values or registers and hence need not be privatized.

Fixes #87216

Author: kiranchandramohan

flang/lib/Lower/OpenMP/DataSharingProcessor.cpp

@@ -339,6 +339,7 @@ void DataSharingProcessor::defaultPrivatize(
     if (!Fortran::semantics::IsProcedure(*sym) &&
         !sym->GetUltimate().has<Fortran::semantics::DerivedTypeDetails>() &&
         !sym->GetUltimate().has<Fortran::semantics::NamelistDetails>() &&
+        !Fortran::semantics::IsImpliedDoIndex(sym->GetUltimate()) &&
         !symbolsInNestedRegions.contains(sym) &&
         !symbolsInParentRegions.contains(sym) &&
         !privatizedSymbols.contains(sym))

flang/test/Lower/OpenMP/default-clause-implied-do-fix.f90

@@ -0,0 +1,11 @@
+!RUN: %flang_fc1 -emit-hlfir -fopenmp %s -o - | FileCheck %s
+
+!CHECK: @_QPsb
+subroutine sb(a)
+  integer :: a(:)
+!CHECK: omp.parallel
+  !$omp parallel default(private)
+!CHECK: hlfir.elemental
+    if (any(a/=(/(100,i=1,5)/))) print *, "OK"
+  !$omp end parallel
+end subroutine