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Re: [tree-ssa] Disastrous simplification of large switch stmt
On Mon, 23 Sep 2002, Diego Novillo wrote:
> > T.134 = "../../gcc/gcc/tree.c";
> > T.135 = (const char *)T.134;
> > T.136 = "make_node";
> > T.137 = (const char *)T.136;
> > tree_class_check_failed (__t, 116, T.135, 317, T.137);
> >
> > For 15 identical cases in the function body, we create 60 temporaries at
> > the entry of the function. And this is only a relatively small switch
> > statement.
> >
> Ah, now I see what you're getting at. In this case copy propagation
^^^^^^^^^^^^^^^^
> should help. Notice that if you had made different scopes for all these
>
Er, constant propagation. Sorry. Right now CCP doesn't do much
more than folding expressions with constants in them. We need to
remove all the dead assignments, conditional jumps and other side
effects of CCP.
Diego.