[PATCH][4.3] Deprecate -ftrapv

[Richard Guenther]

On Sat, 1 Mar 2008, Joseph S. Myers wrote:

> On Sat, 1 Mar 2008, Richard Guenther wrote:
> 
> > This is a request to depcrecate -ftrapv which has numerous problems
> > making it not work as expected since a long time.  As nobody seems
> > to have the energy to ensure it is working I propose to deprecate it
> > for GCC 4.3 to make it possible to remove it during 4.4 (and not
> > block removing libcall notes by it).
> > 
> > Ok for 4.3?  I'll prepare an entry for the changes.html as well.
> 
> If this does need to be deprecated (and it's a feature for which I hope 
> someone will step forward to fix or reimplement it, since we know people 
> have used it to find integer overflow bugs in their code, despite its 
> known limitations), it should give a deprecation warning on all 
> compilations using the option, not just be deprecated in documentation.

I seriously doubt anyone has used it for anything useful since at least
the advent of tree-ssa.  I see we for example warn for -fforce-mem
in 4.2, but that is a no-op there.  Do we have an option to disable
such warnings?  After all it would break -Werror.

Richard.