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Re: [PATCH 00/89] Compile-time gimple-checking

David Malcolm <> writes:
> Alternatively we could change the is-a.h API to eliminate this
> discrepancy, and keep the typedefs; giving something like the following:
>   static void
>   dump_gimple_switch (pretty_printer *buffer, gimple_switch gs, int spc,
>                       int flags)
>   [...snip...]
>   [...later, within pp_gimple_stmt_1:]
>      case GIMPLE_SWITCH:
>        dump_gimple_switch (buffer, as_a <gimple_switch> (gs), spc, flags);
>        break;
> which is concise, readable, and avoid the change in pointerness compared
> to the "gimple" typedef; the local decls above would look like this:
>   gimple some_stmt;  /* note how this doesn't have a star... */
>   gimple_assign assign_stmt; /* ...and neither do these */
>   gimple_cond assign_stmt;
>   gimple_phi phi;
> I think this last proposal is my preferred API, but it requires the
> change to is-a.h
> Attached is a proposed change to the is-a.h API that elimintates the
> discrepancy, allowing the use of typedefs with is-a.h (doesn't yet
> compile, but hopefully illustrates the idea).  Note how it changes the
> API to match C++'s  dynamic_cast<> operator i.e. you do
>   Q* q = dyn_cast<Q*> (p);
> not:
>   Q* q = dyn_cast<Q> (p);

Thanks for being flexible. :-)  I like this version too FWIW, for the
reason you said: it really does look like a proper C++ cast.

If we ever decide to get rid of the typedefs (maybe at the same time as
using "auto") then the choice might be different, but that would be a much
more systematic and easily-automated change than this one.


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