Re: [RFC] Contributing tree-ssa to mainline

[kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)]

    Instead of emitting runtime calls, would it be possible to emit tree
    codes with well defined semantics?  On finding them, the optimizers
    would know that it's not just an arbitrary function call for instance
    (perhaps adding attributes to the libcall).
    
    But I'm oversimplifying.  We would have to talk about specific cases.

You are oversimplifying.  There is a *huge* amount of code generated
that has subtle dependencies on these things.

Just as one example, the representation and generated code for packed
array of Boolean is completely different if the array bounds are constant
and small (say 1..32) vs. if they are variable.

There's no practical way to represent all the different possibilities
and expect language-independent code to choose one based on constant
propagation: it has to be done in the front end or not at all.