[PATH]: PR middlend/38385 fix

Tomas Bily tbily@suse.cz
Sun Dec 7 15:06:00 GMT 2008


> On Thu, Dec 4, 2008 at 5:05 PM, Richard Guenther
> <richard.guenther@gmail.com> wrote:
> > On Thu, Dec 4, 2008 at 4:42 PM, Sebastian Pop <spop@gcc.gnu.org> wrote:
> >> On Thu, Dec 4, 2008 at 8:59 AM, Tomas Bily <tbily@suse.cz> wrote:
> >>> Hi,
> >>>
> >>>  This pr is caused because after removing bbs in generate_builtin
> >>> (tree-loop-distribution.c) some phis has bad incoming edges. This
> >>> patch tryes to fix it.
> >>>
> >>> Tested and bootstraped on x86_64-unknown-linux-gnu.
> >>> Ok for mainline ?
> >>>
> >>
> >> Looks good to me, but I cannot approve it.
> >
> > I don't follow.  You create an edge from the preheader to the loop exit
> > and now use the values from the exit edge for that edge?  If we
> > are in loop-closed SSA form we should not need to care at all here.
> > It is more likely that we need to split some block before removing the
> > loop.
> 
> Err, wait.  These _are_ the loop-closed PHI nodes.  You should be able
> to just remove them by propagation.
> 
> Richard.

I think that all this things does rewrite_into_loop_closed_ssa that is
called after transformation.

Tomas



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