This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [PATCH] Fix optimization regression in constant folder
> "these properties" are those which you and Eric expected sizetype to have,
> and where we then had this very thread to actually try and spell out the
> properties, i.e. those properties which you initially "defined" as "all
> optimizations are allowed".
One can argue about what those properties ought to be, but they clearly
have *some* properties! And there's no particular reason to believe those
should match those of any user-visible type, since they are used in very
different ways than any user-visible type.
> You still weren't able to show a testcase where it matters I believe.
Being able to *show* a test case and *having* one aren't the same! The
problem here is that it's only going to occur in large programs and those
are proprietary. It's a lot of work to sanitize such a large test case.
Conceptually, it's easy to describe: we're talking about records where
there are a large number of variable-length arrays, some of which have the
same index and some of which do not, and we're trying to simplify the
computation of the offset of the later fields ni the record.