This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: Merging CCP and VRP?
On Wed, 2005-03-30 at 13:22 -0500, Diego Novillo wrote:
> On Wed, Mar 30, 2005 at 10:58:39AM -0700, Jeffrey A Law wrote:
>
> > Whatever scheme we use to explicitly expose context sensitive
> > equivalences in the IL needs to be a pure expression.
> >
> Well, that's the fundamental mechanism behind ASSERT_EXPRs and
> VRP. Remember more details about the problem? You're being
> pretty vague.
We'd have to go back and find the PR. I don't remember all the
details, but the problem was big enough to make ASSERT_EXPRs a
far inferior solution to the others I'd looked at for recording
context sensitive equivalences.
>
> > And, yes, it is imperative that we const/copy propagate into
> > ASSERT_EXPRs to the fullest extent possible. Otherwise we lose a lot
> > of threading opportunities.
> >
> ASSERT_EXPRs are regular expressions, so this is not a problem.
It is if you don't run const/copy propagation immediately after
insertion of the ASSERT_EXPRs :-)
jeff