[flang][OpenMP] Try to unify induction var privatization

This PR tries to unify the paths taken by flang to privatize the induction variable of loops. With the changes introduced here, both cases below are now privatized in the same way: ```fortran subroutine nested_constructs implicit none integer :: i !$omp parallel default(private) do i = 1, 10 end do !$omp end parallel end subroutine ``` ```fortran subroutine nested_constructs implicit none integer :: i !$omp parallel private(i) do i = 1, 10 end do !$omp end parallel end subroutine ```

Author: ergawy

flang/lib/Semantics/resolve-directives.cpp

@@ -1674,7 +1674,6 @@ void OmpAttributeVisitor::ResolveSeqLoopIndexInParallelOrTaskConstruct(
  // parallel or task
  if (auto *symbol{ResolveOmp(iv, Symbol::Flag::OmpPrivate, targetIt->scope)}) {
  targetIt++;
- symbol->set(Symbol::Flag::OmpPreDetermined);
  iv.symbol = symbol; // adjust the symbol within region
  for (auto it{dirContext_.rbegin()}; it != targetIt; ++it) {
  AddToContextObjectWithDSA(*symbol, Symbol::Flag::OmpPrivate, *it);

flang/test/Lower/OpenMP/default-clause.f90

@@ -537,16 +537,21 @@ subroutine nested_constructs
 
  integer :: y, z
 !CHECK: omp.parallel {
-!CHECK: %[[INNER_J:.*]] = fir.alloca i32 {bindc_name = "j", pinned}
-!CHECK: %[[INNER_J_DECL:.*]]:2 = hlfir.declare %[[INNER_J]] {{.*}}
-!CHECK: %[[INNER_I:.*]] = fir.alloca i32 {bindc_name = "i", pinned}
-!CHECK: %[[INNER_I_DECL:.*]]:2 = hlfir.declare %[[INNER_I]] {{.*}}
+
 !CHECK: %[[INNER_Y:.*]] = fir.alloca i32 {bindc_name = "y", pinned, uniq_name = "_QFnested_constructsEy"}
 !CHECK: %[[INNER_Y_DECL:.*]]:2 = hlfir.declare %[[INNER_Y]] {{.*}}
 !CHECK: %[[TEMP:.*]] = fir.load %[[Y_DECL]]#0 : !fir.ref<i32>
 !CHECK: hlfir.assign %[[TEMP]] to %[[INNER_Y_DECL]]#0 temporary_lhs : i32, !fir.ref<i32>
+
+!CHECK: %[[INNER_I:.*]] = fir.alloca i32 {bindc_name = "i", pinned, uniq_name
+!CHECK: %[[INNER_I_DECL:.*]]:2 = hlfir.declare %[[INNER_I]] {{.*}}
+
+!CHECK: %[[INNER_J:.*]] = fir.alloca i32 {bindc_name = "j", pinned, uniq_name
+!CHECK: %[[INNER_J_DECL:.*]]:2 = hlfir.declare %[[INNER_J]] {{.*}}
+
 !CHECK: %[[INNER_Z:.*]] = fir.alloca i32 {bindc_name = "z", pinned, uniq_name = "_QFnested_constructsEz"}
 !CHECK: %[[INNER_Z_DECL:.*]]:2 = hlfir.declare %[[INNER_Z]] {{.*}}
+
  !$omp parallel default(private) firstprivate(y)
 !CHECK: {{.*}} = fir.do_loop {{.*}} {
  do i = 1, 10

flang/test/Semantics/OpenMP/do05-positivecase.f90

@@ -9,7 +9,7 @@ program omp_do
  !DEF: /omp_do/n ObjectEntity INTEGER(4)
  integer i,n
  !$omp parallel
- !DEF: /omp_do/OtherConstruct1/i (OmpPrivate, OmpPreDetermined) HostAssoc INTEGER(4)
+ !DEF: /omp_do/OtherConstruct1/i (OmpPrivate) HostAssoc INTEGER(4)
  do i=1,10
  !$omp single
  print *, "hello"

flang/test/Semantics/OpenMP/symbol08.f90

@@ -37,7 +37,7 @@ subroutine test_do
  do j=6,10
  !REF: /test_do/a
  a(1,1,1) = 0.
- !DEF: /test_do/OtherConstruct1/k (OmpPrivate, OmpPreDetermined) HostAssoc INTEGER(4)
+ !DEF: /test_do/OtherConstruct1/k (OmpPrivate) HostAssoc INTEGER(4)
  do k=11,15
  !REF: /test_do/a
  !REF: /test_do/OtherConstruct1/k
@@ -170,9 +170,9 @@ subroutine test_simd
 !$omp parallel do simd
  !DEF: /test_simd/OtherConstruct1/i (OmpLinear, OmpPreDetermined) HostAssoc INTEGER(4)
  do i=1,5
- !DEF: /test_simd/OtherConstruct1/j (OmpPrivate, OmpPreDetermined) HostAssoc INTEGER(4)
+ !DEF: /test_simd/OtherConstruct1/j (OmpPrivate) HostAssoc INTEGER(4)
  do j=6,10
- !DEF: /test_simd/OtherConstruct1/k (OmpPrivate, OmpPreDetermined) HostAssoc INTEGER(4)
+ !DEF: /test_simd/OtherConstruct1/k (OmpPrivate) HostAssoc INTEGER(4)
  do k=11,15
  !REF: /test_simd/a
  !REF: /test_simd/OtherConstruct1/k
@@ -228,7 +228,7 @@ subroutine test_seq_loop
  print *, i, j
  !$omp parallel
  !REF: /test_seq_loop/i
- !DEF: /test_seq_loop/OtherConstruct1/OtherConstruct1/j (OmpPrivate, OmpPreDetermined) HostAssoc INTEGER(4)
+ !DEF: /test_seq_loop/OtherConstruct1/OtherConstruct1/j (OmpPrivate) HostAssoc INTEGER(4)
  print *, i, j
  !$omp do
  !DEF: /test_seq_loop/OtherConstruct1/OtherConstruct1/OtherConstruct1/i (OmpPrivate, OmpPreDetermined) HostAssoc INTEGER(4)