Traced it back to a typo in operator_abs::fold_range() when I did the
conversion where the wrong line got copied in..
Instead of returning value_range (type) when a overflow happens, it was
returning the same result of the previous check, which was the case for
all positives.
This had EVRP setting the range of an ABS to [-MIN, -1] instead of
varying, which later caused VRP to intersect that with 0 - [-MIN, -1]
and all heck broke loose. doh.
I also stumbled across a case where we should be starting with undefined
in the default fold_range() and building with union for each sub-range.
We previously declared a local value_range to work with, and that
defaulted to undefined. When I changed it to a reference parameter, I
need to explicitly initialize it.
Bootstraps, checked in as revision 278259.
Andrew
2019-11-14 Andrew MacLeod <amacl...@redhat.com>
* range-op.cc (range_operator::fold_range): Start with range undefined.
(operator_abs::wi_fold): Fix wrong line copy... With wrapv, abs with
overflow is varying.
Index: range-op.cc
===================================================================
*** range-op.cc (revision 277979)
--- range-op.cc (working copy)
*************** range_operator::fold_range (value_range
*** 146,151 ****
--- 146,152 ----
return;
value_range tmp;
+ r.set_undefined ();
for (unsigned x = 0; x < lh.num_pairs (); ++x)
for (unsigned y = 0; y < rh.num_pairs (); ++y)
{
*************** operator_abs::wi_fold (value_range &r, t
*** 2359,2365 ****
wide_int max_value = wi::max_value (prec, sign);
if (!TYPE_OVERFLOW_UNDEFINED (type) && wi::eq_p (lh_lb, min_value))
{
! r = value_range (type, lh_lb, lh_ub);
return;
}
--- 2360,2366 ----
wide_int max_value = wi::max_value (prec, sign);
if (!TYPE_OVERFLOW_UNDEFINED (type) && wi::eq_p (lh_lb, min_value))
{
! r = value_range (type);
return;
}
