On Tue, Sep 21, 2021 at 7:17 PM Aldy Hernandez via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
>
>
> On 9/21/21 7:05 PM, Andrew MacLeod wrote:
> > On 9/21/21 12:53 PM, Aldy Hernandez wrote:
> >> SCEV won't work without dominators and we can get called without
> >> dominators from debug_ranger.
> >>
> >> Another option would be to rename scev_initialized_p to something like
> >> scev_available_p and move the check there. For now, this will do.
> >>
> >> Committed.
> >>
> >> gcc/ChangeLog:
> >>
> >> * gimple-range-fold.cc (fold_using_range::range_of_phi): Check
> >> dom_info_available_p.
> >> ---
> >> gcc/gimple-range-fold.cc | 4 +++-
> >> 1 file changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/gcc/gimple-range-fold.cc b/gcc/gimple-range-fold.cc
> >> index 997d02dd4b9..4dbf4188ec2 100644
> >> --- a/gcc/gimple-range-fold.cc
> >> +++ b/gcc/gimple-range-fold.cc
> >> @@ -781,7 +781,9 @@ fold_using_range::range_of_phi (irange &r, gphi
> >> *phi, fur_source &src)
> >> }
> >> // If SCEV is available, query if this PHI has any knonwn values.
> >> - if (scev_initialized_p () && !POINTER_TYPE_P (TREE_TYPE (phi_def)))
> >> + if (dom_info_available_p (CDI_DOMINATORS)
> >> + && scev_initialized_p ()
> >> + && !POINTER_TYPE_P (TREE_TYPE (phi_def)))
> >> {
> >> value_range loop_range;
> >> class loop *l = loop_containing_stmt (phi);
> >
> > Im confused.. if scev doesn't work without dominators, how is
> > scev_initialized_p() true if there are no dominators? Are we
> > initializing it somewhere without dominators? Maybe there should be a
> > check in the scev init routine? seems like something else is amok.
>
> As I mentioned, this can happen from debug_ranger(), which is a
> debugging construct, and I've been known to call it without dominators
> :). And yes, I agree we could move it to scev_initialized_p.
But why is scev_initialized_p () true from debug_ranger()?
> Aldy
>
> >
> >
> > void
> > scev_initialize (void)
> > {
> > gcc_assert (! scev_initialized_p ());
> >
> > scalar_evolution_info = hash_table<scev_info_hasher>::create_ggc (100);
> >
> > for (auto loop : loops_list (cfun, 0))
> > loop->nb_iterations = NULL_TREE;
> > }
> >
> > /* Return true if SCEV is initialized. */
> >
> > bool
> > scev_initialized_p (void)
> > {
> > return scalar_evolution_info != NULL;
> > }
> >
> >
>
