[COMMITTED] Clear nonzero mask when inverting ranges.

[Aldy Hernandez via Gcc-patches]

Every time we set a range we should take into account the nonzero
mask.  This happens automatically for the set() methods, plus all the
other assignment, intersect, and union methods.  Unfortunately I
forgot about the invert code.

Also, for good measure I audited the rest of the setters in
value_range.cc and plugged the legacy code to pessimize the masks to
-1 for union/intersect, since we don't support the masks on them (or
rather, we don't keep very good track of them).

Tested on x86-64 Linux.

gcc/ChangeLog:

        * value-range.cc (irange::copy_to_legacy): Set nonzero mask.
        (irange::legacy_intersect): Clear nonzero mask.
        (irange::legacy_union): Same.
        (irange::invert): Same.
---
 gcc/value-range.cc | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/gcc/value-range.cc b/gcc/value-range.cc
index 2aa973b2af2..528ed547ef3 100644
--- a/gcc/value-range.cc
+++ b/gcc/value-range.cc
@@ -331,6 +331,7 @@ irange::copy_to_legacy (const irange &src)
       m_base[0] = src.m_base[0];
       m_base[1] = src.m_base[1];
       m_kind = src.m_kind;
+      m_nonzero_mask = src.m_nonzero_mask;
       return;
     }
   // Copy multi-range to legacy.
@@ -1336,6 +1337,9 @@ irange::legacy_intersect (irange *vr0, const irange *vr1)
   intersect_ranges (&vr0kind, &vr0min, &vr0max,
                    vr1->kind (), vr1->min (), vr1->max ());
 
+  // Pessimize nonzero masks, as we don't support them.
+  m_nonzero_mask = NULL;
+
   /* Make sure to canonicalize the result though as the inversion of a
      VR_RANGE can still be a VR_RANGE.  */
   if (vr0kind == VR_UNDEFINED)
@@ -1657,6 +1661,9 @@ irange::legacy_union (irange *vr0, const irange *vr1)
   union_ranges (&vr0kind, &vr0min, &vr0max,
                vr1->kind (), vr1->min (), vr1->max ());
 
+  // Pessimize nonzero masks, as we don't support them.
+  m_nonzero_mask = NULL;
+
   if (vr0kind == VR_UNDEFINED)
     vr0->set_undefined ();
   else if (vr0kind == VR_VARYING)
@@ -2253,6 +2260,7 @@ irange::invert ()
     }
 
   gcc_checking_assert (!undefined_p () && !varying_p ());
+  m_nonzero_mask = NULL;
 
   // We always need one more set of bounds to represent an inverse, so
   // if we're at the limit, we can't properly represent things.
-- 
2.36.1