[Patch] Silent gcc 4.2.0 loop optimization bug with -O2

[Roman Divacky]

On Wed, Jul 04, 2007 at 11:01:48PM +0400, Andrey Chernov wrote:
> On Wed, Jul 04, 2007 at 02:12:08PM +0200, Ed Schouten wrote:
> > > Index: tree-ssa-loop-niter.c
> > > ===================================================================
> > > --- tree-ssa-loop-niter.c       (revision 126260)
> > > +++ tree-ssa-loop-niter.c       (working copy)
> > > @@ -1747,6 +1747,12 @@ infer_loop_bounds_from_undefined (struct
> > >      {
> > >        bb = bbs[i];
> > > 
> > > +      /* If BB is not executed in each iteration of the loop, we cannot
> > > +        use the operations in it to infer reliable upper bound on the
> > > +        # of iterations of the loop.  */
> > > +      if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb))
> > > +       continue;
> > > +
> > >        for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
> > >          {
> > >           tree stmt = bsi_stmt (bsi);
> > > 
> > > I'm going to test this.
> > > 
> > ----- End forwarded message -----
> > 
> > I just tested the patch on my desktop and it seems to work. The test
> > code now compiles like it should. Hopefully it will be part of 4.2.1.
> 
> Will be nice if this patch will be commited in instead of my 
> sys.mk workaround. Alexander?

afaik they plan to release gcc 4.2.1 on July 13th, thats a week, possibly two ahead.
maybe we can wait and import the 4.2.1 directly. 4.2.1 contains some more bug fixes
so it would be worth it.

roman