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Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
- From: Andrew Pinski <pinskia at physics dot uc dot edu>
- To: dewar at adacore dot com (Robert Dewar)
- Cc: gdr at integrable-solutions dot net (Gabriel Dos Reis), richard dot guenther at gmail dot com (Richard Guenther), kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner), ebb9 at byu dot net, autoconf-patches at gnu dot org, bernds_cb1 at t-online dot de, bug-gnulib at gnu dot org, eggert at cs dot ucla dot edu, gcc at gcc dot gnu dot org, pinskia at physics dot uc dot edu
- Date: Sat, 30 Dec 2006 18:57:12 -0500 (EST)
- Subject: Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
>
> Gabriel Dos Reis wrote:
>
> > I have been looking into infer_loop_bounds_from_signedness() called
> > from infer_loop_bounds_from_undefined().
> > At some places, nowrap_type_p() is used but this function operates
> > only on types, so there will be too many false positive there; yet we
> > will miss warning through that case.
>
> My inclination is to skip the warning for the loop
> induction variable case. I think this will generate
> lots of false positives, and almost no useful
> warnings (I still think this is the one and only
> case where the undefined optimization should be done,
> in fact I think it would be useful to have a switch
> that says
>
> -fwrapv-in-all-cases-except-loop-bounds
Again, please don't this the default for Fortran as integer
overflow has been undefined since at least 1977 so I don't think
it is a good idea for GCC in general anyways as evidence of Fortran.
-- Pinski