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Re: [lto/pph] Do not pack more bits than requested (issue4415044)
On Fri, 15 Apr 2011, Diego Novillo wrote:
> On Fri, Apr 15, 2011 at 04:56, Richard Guenther <rguenther@suse.de> wrote:
>
> >> @@ -518,7 +518,8 @@ pack_ts_type_value_fields (struct bitpack_d *bp, tree expr)
> >> Â Âbp_pack_value (bp, TYPE_USER_ALIGN (expr), 1);
> >> Â Âbp_pack_value (bp, TYPE_READONLY (expr), 1);
> >> Â Âbp_pack_value (bp, TYPE_ALIGN (expr), HOST_BITS_PER_INT);
> >> - Âbp_pack_value (bp, TYPE_ALIAS_SET (expr) == 0 ? 0 : -1, HOST_BITS_PER_INT);
> >> + Âbp_pack_value (bp, TYPE_ALIAS_SET (expr) == 0 ? 0 : -1,
> >> + Â Â Â Â Â Â Â ÂBITS_PER_BITPACK_WORD);
> >
> > As we only want to stream alias-set zeros just change it to a single bit,
> > like
> >
> > Â Â bp_pack_value (bp, TYPE_ALIAS_SET (expr) == 0, 1);
> >
> > and on the reader side restore either a zero or -1.
>
> Ah, yes. Much better.
>
> > As for the -1 case, it's simply broken use of the interface.
>
> Which would've been caught by the assertion. How about this, we keep
> the asserts with #ifdef ENABLE_CHECKING. This would've saved me some
> ugly debugging.
I think we should rather add the masking. The assert would only
trigger for particular values, not for bogus use of the interface
(you get sign-extension for signed arguments).
Richard.