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Re: [RFC] Tightening up the type system

From: Jan Hubicka <hubicka at ucw dot cz>
To: Andrew Haley <aph at redhat dot com>
Cc: Diego Novillo <dnovillo at redhat dot com>,"gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
Date: Tue, 28 Sep 2004 19:16:41 +0200
Subject: Re: [RFC] Tightening up the type system
References: <1096385758.18087.55.camel@localhost.localdomain> <16729.39370.815293.198564@cuddles.cambridge.redhat.com>

> Diego Novillo writes:
>  > 
>  > 
>  > My question to the FE folks is: what are the right semantics for
>  > checking MODIFY_EXPR?  Is compatible_types_p too strict?  Should we have
>  > had a cast operation in the above assignment?
>  > 
>  > Not having the right types is increasingly getting in the way of the
>  > optimizers because we use compatible_types_p quite often to validate
>  > propagation opportunities.
> 
> It's an interesting view.  I'm pretty sure that we violate this is the
> Java FE in a few places, but perhaps we shouldn't.  The trouble is
> that the GENERIC type system has never been so well-defined.
> 
> I'm sure that enforcing this would break things and it would take some
> time to find and fix them all. 

Also note that in the archives should be simply type checking code for
verify_stmts I implemented while back.  It also had trouble witht he way
we elliminate useless NOP_EXPR conversions

Honza

References:
- [RFC] Tightening up the type system
  - From: Diego Novillo
- [RFC] Tightening up the type system
  - From: Andrew Haley

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