We just replaced SmallSet<T *, N> with SmallPtrSet<T *, N>, bypassing
the redirection found in SmallSet.h.  With that, we no longer need to
include SmallSet.h in many files.

insertParsePoints collects live variables and then deduplicate them
while retaining the original insertion order, which is exactly what
SetVector is designed for.  This patch replaces SmallVector with
SetSmallVector while deleting unique_unsorted.

While we are at it, this patch reduces the number of inline elements
to a reasonable level for linear search.

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.

This patch add cost kind to `getAddressComputationCost()` for #149955.

Note that this patch also remove all the default value in `getAddressComputationCost()`. 

In some places we were passing the type of value being accessed, in
other cases we were passing the type of the pointer for the access.

The most "involved" user is
LoopVectorizationCostModel::getMemInstScalarizationCost, which is the
only call site that passes in the SCEV, and it passes along the pointer
type.

This changes call sites to consistently pass the pointer type, and
renames the arguments to clarify this.

No target actually checks the contents of the type passed, only to see
if it's a vector or not, so this shouldn't have an effect.

Migrate their usage to the `AnyMem*Inst` family, and add a isAtomic()
query on the base class for that hierarchy. This matches the idioms we
use for e.g. isAtomic on load, store, etc.. instructions, the existing
isVolatile idioms on mem* routines, and allows us to more easily share
code between atomic and non-atomic variants.

As with #138568, the goal here is to simplify the class hierarchy and
make it easier to reason about. I'm moving from easiest to hardest, and
will stop at some point when I hit "good enough". Longer term, I'd sorta
like to merge or reverse the naming on the plain Mem*Inst and the
AnyMem*Inst, but that's a much larger and more risky change. Not sure
I'm going to actually do that.

Add support for specifying range attributes in Intrinsics.td. Use this
to specify the ucmp/scmp range [-1,2).

This case is trickier than existing intrinsic attributes, because we
need to create the attribute with the correct bitwidth. As such, the
attribute construction now needs to be aware of the function type.

We also need to be careful to no longer assign attributes on intrinsics
with invalid signatures, as we'd make invalid assumptions about the
number of arguments etc otherwise.

Fixes https://github.com/llvm/llvm-project/issues/130179.