In some cases, a clause on a composite simd construct applied to simd
can be using a symbol that is also used by another privatizer, not
applied to simd. Correctly handle this scenario by checking which
directive the privatizer is being generated for while determining
whether to emit the copy region.

Fixes #155195.

Signed-off-by: Kajetan Puchalski <kajetan.puchalski@arm.com>

I'm trying to remove the redirection in SmallSet.h:

template <typename PointeeType, unsigned N>
class SmallSet<PointeeType*, N> : public SmallPtrSet<PointeeType*, N>
{};

to make it clear that we are using SmallPtrSet.  There are only
handful places that rely on this redirection.

This patch replaces SmallSet to SmallPtrSet where the element type is
a pointer.

See https://github.com/llvm/llvm-project/pull/147168 for more info.

This PR proposes re-modelling `reduce` specifiers to match OpenMP and
OpenACC. In particular, this PR includes the following:

* A new `fir` op: `fir.delcare_reduction` which is identical to OpenMP's
`omp.declare_reduction` op.
* Updating the `reduce` clause on `fir.do_concurrent.loop` to use the
new op.
* Re-uses the `ReductionProcessor` component to emit reductions for `do
concurrent` just like we do for OpenMP. To do this, the
`ReductionProcessor` had to be refactored to be more generalized.
* Upates mapping `do concurrent` to `fir.loop ... unordered` nests using
the new reduction model.

Unfortunately, this is a big PR that would be difficult to divide up in
smaller parts because the bottom of the changes are the `fir` table-gen
changes to `do concurrent`. However, doing these MLIR changes cascades
to the other parts that have to be modified to not break things.

This PR goes in the same direction we went for `private/local`
speicifiers. Now the `do concurrent` and OpenMP (and OpenACC) dialects
are modelled in essentially the same way which makes mapping between
them more trivial, hopefully.

PR stack:
- https://github.com/llvm/llvm-project/pull/145837 (this one)
- https://github.com/llvm/llvm-project/pull/146025
- https://github.com/llvm/llvm-project/pull/146028
- https://github.com/llvm/llvm-project/pull/146033

Fixes the build failure due to missing includes introduced in
f8dcb059ae06376b0991936026d5befb3d7b109b.

Extends support for locality specifiers in `do concurrent` by supporting
data types that need `init` regions.

This further unifies the paths taken by the compiler for OpenMP
privatization clauses and `do concurrent` locality specifiers.

Refactors the utils needed to create privtization/locatization ops for
both the fir and OpenMP dialects into a shared location isolating OpenMP
stuff out of it as much as possible.

Bring the typed expression representation of a coindexed reference up to
F'2023, which removed some restrictions that had allowed the current
representation to suffice for older revisions of the language. This new
representation is somewhat more simple -- it uses a DataRef as its base,
so any subscripts in a part-ref can be represented as an ArrayRef there.

Update the code that creates the CoarrayRef, and add more checking to
it, as well as actually capturing any STAT=, TEAM=, & TEAM_NUMBER=
specifiers that might appear. Enforce the constraint that the part-ref
must have subscripts if it is an array. (And update a pile of
copied-and-pasted test code that lacked such subscripts.)

This also includes comparing the two ImpliedDo

Details
- For ArrayConstructor, check if x and y have the same
  elements and type
- For ImpliedDo, check if x and y have the same lower,
  upper, stride and values

Fixes: https://github.com/llvm/llvm-project/issues/104526