------- Additional Comments From law at redhat dot com 2005-07-27 16:55 -------
Subject: Re: [4.1 Regression] vrp produces
wrong code
On Wed, 2005-07-27 at 16:34 +0000, ja2morri at csclub dot uwaterloo dot
ca wrote:
> ------- Additional Comments From ja2morri at csclub dot uwaterloo dot ca
> 2005-07-27 16:34 -------
> Subject: Re: [4.1 Regression] vrp produces
> wrong code
>
>
> Jeffrey A Law <[EMAIL PROTECTED]> writes:
>
> > The underlying problem here is the code to meet a VR_ANTI_RANGE and
> > a VR_RANGE does not intersect the equivalence sets. This in turn
> > causes the VRP code to incorrectly evaluate a conditional. It's
> > all downhill after that.
> >
> > While investigating this problem I also noticed that the vrp_meet
> > code does not properly handle intersecting the equivalence sets
> > when vr0 has a set, but vr1 does not (their intersection is the
> > null set of course). This patch fixes that oversight as well.
> >
> > Bootstrapped and regression tested on i686-pc-linux-gnu.
> >
> > jeff
>
> You added 3 bitmap_clear calls here, do you have any testcases that
> exercise this code?
No, but the code is clearly wrong by inspection.
jeff
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22630
