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Re: [PATCH][RFC] A GIMPLE and "GIMPLE type system" verifier
On Fri, 1 Jun 2007, Richard Kenner wrote:
> > The other option i proposed was to add a new field called
> > TYPE_EQUIVALENCE, representing the equivalence set of a type. The
> > gimpliifer would simply unify all types using some equivalence metric
> > (structural, name, whatever), applied uniformly to all types. Two
> > types are equivalent if they have the same TYPE_EQUIVALENCE.
>
> What I don't understand is why the middle-end or anything past it would care
> about the front-end view of what types are equivalent. Isn't it too late to
> matter?
>
> Why isn't the only thing that matters to GIMPLE whether two types will
> generate the same RTL?
It is (should be) that way. If you disable calling into the frontend
in tree_ssa_useless_type_conversion_1 you should only get some more
explicit conversions and a few testsuite regressions due to missed
optimizations. At least the last time I tried.
Richard.