[flang][Lower] get ultimate symbol when querying if pointer or allocatable (#99528)

This fixes a bug in OpenMP privatisation. The privatised variables are
created as though they are host associated clones of the original
variables. These privatised variables do not contain the allocatable
attribute themselves and so we need to check if the ultimate symbol is
allocatable. Having or not having this flag influences whether lowering
determines that this is a whole allocatable assignment, which then
causes hlfir.assign not to get the realloc flag, which cases the
allocatable not to be allocated when it is assigned to (leading to a
segfault running the newly added test).

I also did the same for pointer variables because I would imagine they
could experience the same issue.

There is no fallout on tests outside of OpenMP, and the gfortran test
suite still passes, so I think this doesn't break host other kinds of
host associated symbols.

Author: tblah

flang/lib/Lower/Allocatable.cpp

@@ -1104,14 +1104,14 @@ void Fortran::lower::associateMutableBox(
 bool Fortran::lower::isWholeAllocatable(const Fortran::lower::SomeExpr &expr) {
   if (const Fortran::semantics::Symbol *sym =
           Fortran::evaluate::UnwrapWholeSymbolOrComponentDataRef(expr))
-    return Fortran::semantics::IsAllocatable(*sym);
+    return Fortran::semantics::IsAllocatable(sym->GetUltimate());
   return false;
 }
 
 bool Fortran::lower::isWholePointer(const Fortran::lower::SomeExpr &expr) {
   if (const Fortran::semantics::Symbol *sym =
           Fortran::evaluate::UnwrapWholeSymbolOrComponentDataRef(expr))
-    return Fortran::semantics::IsPointer(*sym);
+    return Fortran::semantics::IsPointer(sym->GetUltimate());
   return false;
 }
 

flang/test/Lower/OpenMP/firstprivate-allocatable.f90

@@ -0,0 +1,25 @@
+! RUN: bbc -emit-hlfir -fopenmp -o - %s | FileCheck %s
+! RUN: %flang_fc1 -emit-hlfir -fopenmp -o - %s | FileCheck %s
+
+program firstprivateallocatable
+  Integer, Allocatable :: a,u
+  a = 137
+
+  !$omp parallel firstprivate(a,u)
+  u = a**2
+  !$omp end parallel
+end program
+
+
+! CHECK-LABEL:   func.func @_QQmain()
+! [...]
+! CHECK:           omp.parallel {
+! [...]
+! CHECK:             %[[VAL_50:.*]] = arith.constant 2 : i32
+! CHECK:             %[[VAL_51:.*]] = math.ipowi %{{.*}}, %[[VAL_50]] : i32
+! this is what we are really checking: the hlfir.assign must have realloc so that
+! u is allocated when the assignment occurs
+! CHECK:             hlfir.assign %[[VAL_51]] to %{{.*}}#0 realloc : i32, !fir.ref<!fir.box<!fir.heap<i32>>>
+! [...]
+! CHECK:             omp.terminator
+! CHECK:           }

flang/test/Lower/OpenMP/wsloop-reduction-allocatable-array-minmax.f90

@@ -244,8 +244,7 @@ program reduce15
 ! CHECK:                   %[[VAL_85:.*]] = arith.select %[[VAL_84]], %[[VAL_76]], %[[VAL_83]] : i32
 ! CHECK:                   hlfir.yield_element %[[VAL_85]] : i32
 ! CHECK:                 }
-! CHECK:                 %[[VAL_86:.*]] = fir.load %[[VAL_62]]#0 : !fir.ref<!fir.box<!fir.heap<!fir.array<?xi32>>>>
-! CHECK:                 hlfir.assign %[[VAL_68]] to %[[VAL_86]] : !hlfir.expr<?xi32>, !fir.box<!fir.heap<!fir.array<?xi32>>>
+! CHECK:                 hlfir.assign %[[VAL_68]] to %[[VAL_62]]#0 realloc : !hlfir.expr<?xi32>, !fir.ref<!fir.box<!fir.heap<!fir.array<?xi32>>>>
 ! CHECK:                 hlfir.destroy %[[VAL_68]] : !hlfir.expr<?xi32>
 ! CHECK:                 omp.yield
 ! CHECK:               }
@@ -288,8 +287,7 @@ program reduce15
 ! CHECK:                   %[[VAL_117:.*]] = arith.select %[[VAL_116]], %[[VAL_108]], %[[VAL_115]] : i32
 ! CHECK:                   hlfir.yield_element %[[VAL_117]] : i32
 ! CHECK:                 }
-! CHECK:                 %[[VAL_118:.*]] = fir.load %[[VAL_94]]#0 : !fir.ref<!fir.box<!fir.heap<!fir.array<?xi32>>>>
-! CHECK:                 hlfir.assign %[[VAL_100]] to %[[VAL_118]] : !hlfir.expr<?xi32>, !fir.box<!fir.heap<!fir.array<?xi32>>>
+! CHECK:                 hlfir.assign %[[VAL_100]] to %[[VAL_94]]#0 realloc : !hlfir.expr<?xi32>, !fir.ref<!fir.box<!fir.heap<!fir.array<?xi32>>>>
 ! CHECK:                 hlfir.destroy %[[VAL_100]] : !hlfir.expr<?xi32>
 ! CHECK:                 omp.yield
 ! CHECK:               }

flang/test/Lower/OpenMP/wsloop-reduction-allocatable.f90

@@ -85,9 +85,7 @@ program reduce
 ! CHECK:                 %[[VAL_16:.*]]:2 = hlfir.declare %[[VAL_14]] {fortran_attrs = {{.*}}<allocatable>, uniq_name = "_QFEr"} : (!fir.ref<!fir.box<!fir.heap<i32>>>) -> (!fir.ref<!fir.box<!fir.heap<i32>>>, !fir.ref<!fir.box<!fir.heap<i32>>>)
 ! CHECK:                 fir.store %[[VAL_15]] to %[[VAL_10]]#1 : !fir.ref<i32>
 ! CHECK:                 %[[VAL_17:.*]] = fir.load %[[VAL_10]]#0 : !fir.ref<i32>
-! CHECK:                 %[[VAL_18:.*]] = fir.load %[[VAL_16]]#0 : !fir.ref<!fir.box<!fir.heap<i32>>>
-! CHECK:                 %[[VAL_19:.*]] = fir.box_addr %[[VAL_18]] : (!fir.box<!fir.heap<i32>>) -> !fir.heap<i32>
-! CHECK:                 hlfir.assign %[[VAL_17]] to %[[VAL_19]] : i32, !fir.heap<i32>
+! CHECK:                 hlfir.assign %[[VAL_17]] to %[[VAL_16]]#0 realloc : i32, !fir.ref<!fir.box<!fir.heap<i32>>>
 ! CHECK:                 omp.yield
 ! CHECK:               }
 ! CHECK:               omp.terminator