This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: [tree-ssa-branch] Optimizing non-SIMPLE trees
> On Sat, 2002-08-10 at 17:31, Richard Henderson wrote:
>
> > > 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.
> >
> That's exactly what we're doing now. Trees that cannot be simplified
> are flagged TF_NOT_SIMPLE. This causes the reference finder to create
> definitions for all the symbols referenced by the expression. Safe and
> easy.
Is this necesary? The builtins behave like real C functions, so they
don't modify their arguments.
I would believe that it is wortwhile to invest energy into simplifying
everything around to avoid creating of tons of special cases like we
have in RTL.
Honza