Re: [tree-ssa-branch] Optimizing non-SIMPLE trees

[Richard Henderson <rth at redhat dot com>]

On Sat, Aug 10, 2002 at 02:15:12AM -0400, Diego Novillo wrote:
> Just the other day we were talking about trees that would need to
> be passed unsimplified.

I didn't buy it then either.

> You have to tell the optimizers that they cannot look *into* those
> trees.  MD builtins have this problem as well, we can't really
> simplify those trees as we don't know what the backend might expect.

You won't be incorrect if you treat them like a regular
function call.

> Builtin functions are always expanded after constant propagation.
> Aren't builtins expanded as part of the tree->RTL expansion?

Not all of them.  See fold_builtin.

> Will fold() deal with __builtin_strncmp if all its arguments are
> constants?

Apparently not, though it ought to.


r~