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Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."

On Sat, Dec 30, 2006 at 08:57:12PM -0500, Richard Kenner wrote:
> > I suppose there is
> > 
> >       *hv = (HOST_WIDE_INT) -(unsigned HOST_WIDE_INT) h1;
> > 
> > to make it safe.
> 
> Can't that conversion overflow?

Not on a two's complement machine, and I know of no gcc ports
to a non-two's-complement host machine.  unary minus is
well-defined for all unsigned values even on non-two's-complement
machines, but for those we'd have to worry about the mapping
between unsigned and signed types.
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