[gcc r13-2797] Convert CFN_BUILT_IN_STRLEN to range-ops.

[gcc r13-2797] Convert CFN_BUILT_IN_STRLEN to range-ops.

[Andrew Macleod]

https://gcc.gnu.org/g:c750e675cb77f283ff991682db7740bc5f6d4cf4

commit r13-2797-gc750e675cb77f283ff991682db7740bc5f6d4cf4
Author: Andrew MacLeod <amacleod@redhat.com>
Date:   Tue Sep 20 19:05:03 2022 -0400

    Convert CFN_BUILT_IN_STRLEN to range-ops.
    
            * gimple-range-fold.cc (range_of_builtin_int_call): Remove case
            for CFN_BUILT_IN_STRLEN.
            * gimple-range-op.cc (class cfn_strlen): New.
            (gimple_range_op_handler::maybe_builtin_call): Set arguments.

Diff:
---
 gcc/gimple-range-fold.cc | 21 ---------------------
 gcc/gimple-range-op.cc   | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 21 deletions(-)

diff --git a/gcc/gimple-range-fold.cc b/gcc/gimple-range-fold.cc
index d445270417a..d22fb0e9352 100644
--- a/gcc/gimple-range-fold.cc
+++ b/gcc/gimple-range-fold.cc
@@ -908,27 +908,6 @@ fold_using_range::range_of_builtin_int_call (irange &r, gcall *call,
 	return true;
       }
 
-    case CFN_BUILT_IN_STRLEN:
-      if (tree lhs = gimple_call_lhs (call))
-	if (ptrdiff_type_node
-	    && (TYPE_PRECISION (ptrdiff_type_node)
-		== TYPE_PRECISION (TREE_TYPE (lhs))))
-	  {
-	    tree type = TREE_TYPE (lhs);
-	    tree max = vrp_val_max (ptrdiff_type_node);
-	    wide_int wmax
-	      = wi::to_wide (max, TYPE_PRECISION (TREE_TYPE (max)));
-	    tree range_min = build_zero_cst (type);
-	    // To account for the terminating NULL, the maximum length
-	    // is one less than the maximum array size, which in turn
-	    // is one less than PTRDIFF_MAX (or SIZE_MAX where it's
-	    // smaller than the former type).
-	    // FIXME: Use max_object_size() - 1 here.
-	    tree range_max = wide_int_to_tree (type, wmax - 2);
-	    r.set (range_min, range_max);
-	    return true;
-	  }
-      break;
     default:
       break;
     }
diff --git a/gcc/gimple-range-op.cc b/gcc/gimple-range-op.cc
index 09b7dd2add3..f9161b5820f 100644
--- a/gcc/gimple-range-op.cc
+++ b/gcc/gimple-range-op.cc
@@ -611,6 +611,30 @@ cfn_ubsan op_cfn_ubsan_add (PLUS_EXPR);
 cfn_ubsan op_cfn_ubsan_sub (MINUS_EXPR);
 cfn_ubsan op_cfn_ubsan_mul (MULT_EXPR);
 
+
+// Implement range operator for CFN_BUILT_IN_STRLEN
+class cfn_strlen : public range_operator
+{
+public:
+  using range_operator::fold_range;
+  virtual bool fold_range (irange &r, tree type, const irange &,
+			   const irange &, relation_kind) const
+  {
+    tree max = vrp_val_max (ptrdiff_type_node);
+    wide_int wmax
+      = wi::to_wide (max, TYPE_PRECISION (TREE_TYPE (max)));
+    tree range_min = build_zero_cst (type);
+    // To account for the terminating NULL, the maximum length
+    // is one less than the maximum array size, which in turn
+    // is one less than PTRDIFF_MAX (or SIZE_MAX where it's
+    // smaller than the former type).
+    // FIXME: Use max_object_size() - 1 here.
+    tree range_max = wide_int_to_tree (type, wmax - 2);
+    r.set (range_min, range_max);
+    return true;
+  }
+} op_cfn_strlen;
+
 // Set up a gimple_range_op_handler for any built in function which can be
 // supported via range-ops.
 
@@ -711,6 +735,19 @@ gimple_range_op_handler::maybe_builtin_call ()
       m_int = &op_cfn_ubsan_mul;
       break;
 
+    case CFN_BUILT_IN_STRLEN:
+      {
+	tree lhs = gimple_call_lhs (call);
+	if (lhs && ptrdiff_type_node && (TYPE_PRECISION (ptrdiff_type_node)
+					 == TYPE_PRECISION (TREE_TYPE (lhs))))
+	  {
+	    m_op1 = gimple_call_arg (call, 0);
+	    m_valid = true;
+	    m_int = &op_cfn_strlen;
+	  }
+	break;
+      }
+
     default:
       break;
     }