[gcc(refs/users/aldyh/heads/ranger-staging)] parity with evrp.

[gcc(refs/users/aldyh/heads/ranger-staging)] parity with evrp.

[Andrew Macleod]

https://gcc.gnu.org/g:d88d33f898acb2d7e6f760de3f39966f0c22e3c5

commit d88d33f898acb2d7e6f760de3f39966f0c22e3c5
Author: Andrew MacLeod <amacleod@redhat.com>
Date:   Fri Aug 21 14:35:57 2020 -0400

    parity with evrp.
    
    dont use globally set SSA_NAME_RANGE_INFOs  breaks unreachable tests pr61034.C
    / 0 now returns varying , not undefined.   pr61839_2.c

Diff:
---
 gcc/gimple-range.h | 7 +++++++
 gcc/range-op.cc    | 4 ++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/gcc/gimple-range.h b/gcc/gimple-range.h
index 5e301bc0827..329f509b20c 100644
--- a/gcc/gimple-range.h
+++ b/gcc/gimple-range.h
@@ -125,6 +125,12 @@ gimple_range_global (tree name)
 {
   gcc_checking_assert (gimple_range_ssa_p (name));
   tree type = TREE_TYPE (name);
+#if 0
+  // Reenable picking up global ranges when we are OK failing tests that look
+  // for builtin_unreachable in the code, like
+  // RUNTESTFLAGS=dg.exp=pr61034.C check-g++
+  // pre-optimizations (inlining) set a global range which causes the ranger
+  // to remove the condition which leads to builtin_unreachable
   if (!POINTER_TYPE_P (type) && SSA_NAME_RANGE_INFO (name))
     {
       // Return a range from an SSA_NAME's available range.
@@ -132,6 +138,7 @@ gimple_range_global (tree name)
       enum value_range_kind kind = get_range_info (name, &min, &max);
       return value_range (type, min, max, kind);
     }
+#endif
  // Otherwise return range for the type.
  return value_range (type);
 }
diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index 310723dd311..b49c2c71dff 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -1317,10 +1317,10 @@ operator_div::wi_fold (irange &r, tree type,
 		       const wide_int &lh_lb, const wide_int &lh_ub,
 		       const wide_int &rh_lb, const wide_int &rh_ub) const
 {
-  // If we know we will divide by zero, return undefined.
+  // If we know we will divide by zero, return varying.
   if (rh_lb == 0 && rh_ub == 0)
     {
-      r.set_undefined ();
+      r.set_varying (type);
       return;
     }