Implement operator_pointer_diff::fold_range

prange has no default fold_range processing like irange does, so each
pointer specific operator needs to implement its own fold routine.

	PR tree-optimization/117222
	gcc/
	* range-op-ptr.cc (operator_pointer_diff::fold_range): New.
	(operator_pointer_diff::op1_op2_relation_effect): Remove irange
	variant.
	(operator_pointer_diff::update_bitmask): Likewise.

	gcc/testsuite
	* g++.dg/pr117222.C: New.

Author: andrewwmacleod

gcc/range-op-ptr.cc

@@ -567,25 +567,38 @@ pointer_or_operator::wi_fold (irange &r, tree type,
 
 class operator_pointer_diff : public range_operator
 {
+  using range_operator::fold_range;
   using range_operator::update_bitmask;
   using range_operator::op1_op2_relation_effect;
-  virtual bool op1_op2_relation_effect (irange &lhs_range,
-					tree type,
-					const irange &op1_range,
-					const irange &op2_range,
-					relation_kind rel) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const prange &op1,
+			   const prange &op2,
+			   relation_trio trio) const final override;
   virtual bool op1_op2_relation_effect (irange &lhs_range,
 					tree type,
 					const prange &op1_range,
 					const prange &op2_range,
 					relation_kind rel) const final override;
-  void update_bitmask (irange &r, const irange &lh, const irange &rh) const
-    { update_known_bitmask (r, POINTER_DIFF_EXPR, lh, rh); }
   void update_bitmask (irange &r,
 		       const prange &lh, const prange &rh) const final override
   { update_known_bitmask (r, POINTER_DIFF_EXPR, lh, rh); }
 } op_pointer_diff;
 
+bool
+operator_pointer_diff::fold_range (irange &r, tree type,
+				   const prange &op1,
+				   const prange &op2,
+				   relation_trio trio) const
+{
+  gcc_checking_assert (r.supports_type_p (type));
+
+  r.set_varying (type);
+  relation_kind rel = trio.op1_op2 ();
+  op1_op2_relation_effect (r, type, op1, op2, rel);
+  update_bitmask (r, op1, op2);
+  return true;
+}
+
 bool
 operator_pointer_diff::op1_op2_relation_effect (irange &lhs_range, tree type,
 						const prange &op1_range,
@@ -602,16 +615,6 @@ operator_pointer_diff::op1_op2_relation_effect (irange &lhs_range, tree type,
   return minus_op1_op2_relation_effect (lhs_range, type, op1, op2, rel);
 }
 
-bool
-operator_pointer_diff::op1_op2_relation_effect (irange &lhs_range, tree type,
-						const irange &op1_range,
-						const irange &op2_range,
-						relation_kind rel) const
-{
-  return minus_op1_op2_relation_effect (lhs_range, type, op1_range, op2_range,
-					rel);
-}
-
 bool
 operator_identity::fold_range (prange &r, tree type ATTRIBUTE_UNUSED,
 			       const prange &lh ATTRIBUTE_UNUSED,

gcc/testsuite/g++.dg/pr117222.C

@@ -0,0 +1,16 @@
+// { dg-do compile }
+// { dg-require-effective-target c++11 }
+// { dg-options "-O3 -fdump-tree-evrp" }
+
+#include <vector>
+int main()
+{
+    std::vector<int> c {1,2,3,0};
+    while(c.size() > 0 && c.back() == 0)
+    {
+        auto sz = c.size() -1;
+        c.resize(sz);
+    }
+    return 0;
+}
+/* { dg-final { scan-tree-dump "Global Exported.*\[-INF, -1\]\[1, +INF\]" "evrp" } } */