Proposed location for variable sizes etc in ARRAY_REF and COMPONENT_REF

[Richard Kenner]

    I see no reason why we'd always use these nodes for the optimizers.
    I'd only use them when needed.

To reduce the amount of code that needs to check for all the different
node types.

But I'm still leaning towards some sort of "out of the node" representation
of these values, either using a new expression annotation or a hash table.
The fact that is that for all languages, including Ada, the *vast* majority
of such nodes won't need these values and it seems overkill to double the
cost of checks for arrays all over the compiler.