[gcc r13-2795] Convert CFN_BUILT_IN_CLRSB to range-ops.

[gcc r13-2795] Convert CFN_BUILT_IN_CLRSB to range-ops.

[Andrew Macleod]

https://gcc.gnu.org/g:f7e62b09300b6935bceaffb4c42f6edab80f52dc

commit r13-2795-gf7e62b09300b6935bceaffb4c42f6edab80f52dc
Author: Andrew MacLeod <amacleod@redhat.com>
Date:   Tue Sep 20 18:21:04 2022 -0400

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

Diff:
---
 gcc/gimple-range-fold.cc |  7 -------
 gcc/gimple-range-op.cc   | 23 +++++++++++++++++++++++
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/gcc/gimple-range-fold.cc b/gcc/gimple-range-fold.cc
index 96a138a7a02..1d7d1da7bbe 100644
--- a/gcc/gimple-range-fold.cc
+++ b/gcc/gimple-range-fold.cc
@@ -916,8 +916,6 @@ fold_using_range::range_of_builtin_int_call (irange &r, gcall *call,
     return false;
 
   tree type = gimple_range_type (call);
-  tree arg;
-  int prec;
   scalar_int_mode mode;
 
   switch (func)
@@ -926,11 +924,6 @@ fold_using_range::range_of_builtin_int_call (irange &r, gcall *call,
       r.set (build_zero_cst (type), build_one_cst (type));
       return true;
 
-    CASE_CFN_CLRSB:
-      arg = gimple_call_arg (call, 0);
-      prec = TYPE_PRECISION (TREE_TYPE (arg));
-      r.set (build_int_cst (type, 0), build_int_cst (type, prec - 1));
-      return true;
     case CFN_UBSAN_CHECK_ADD:
       range_of_builtin_ubsan_call (r, call, PLUS_EXPR, src);
       return true;
diff --git a/gcc/gimple-range-op.cc b/gcc/gimple-range-op.cc
index 801c2bb235e..bee225431e8 100644
--- a/gcc/gimple-range-op.cc
+++ b/gcc/gimple-range-op.cc
@@ -559,6 +559,23 @@ cfn_ctz::fold_range (irange &r, tree type, const irange &lh,
   return true;
 }
 
+
+// Implement range operator for CFN_BUILT_IN_
+class cfn_clrsb : public range_operator
+{
+public:
+  using range_operator::fold_range;
+  virtual bool fold_range (irange &r, tree type, const irange &lh,
+			   const irange &, relation_kind) const
+  {
+    if (lh.undefined_p ())
+      return false;
+    int prec = TYPE_PRECISION (lh.type ());
+    r.set (build_int_cst (type, 0), build_int_cst (type, prec - 1));
+    return true;
+  }
+} op_cfn_clrsb;
+
 // Set up a gimple_range_op_handler for any built in function which can be
 // supported via range-ops.
 
@@ -632,6 +649,12 @@ gimple_range_op_handler::maybe_builtin_call ()
 	m_int = &op_cfn_ctz;
       break;
 
+    CASE_CFN_CLRSB:
+      m_op1 = gimple_call_arg (call, 0);
+      m_valid = true;
+      m_int = &op_cfn_clrsb;
+      break;
+
     default:
       break;
     }