VM-codegen: Add IL instruction to check if a Smi is in a constant range

runtime/vm/constant_propagator.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/constant_propagator.h"
 
 #include "vm/bit_vector.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/flow_graph_range_analysis.h"
@@ skipping 413 matching lines @@
   } else if (IsConstant(value)) {
     ASSERT(!value.IsNull());
     ASSERT(value.IsBool());
     bool result = Bool::Cast(value).value();
     SetValue(instr, Smi::Handle(Z, Smi::New(result ? instr->if_true()
                                                    : instr->if_false())));
   }
 }
 
 
+void ConstantPropagator::VisitSmiRangeComparison(
+    SmiRangeComparisonInstr* instr) {
+  Definition* defn = instr->input()->definition();
+  const Object& value = defn->constant_value();
+  if (IsConstant(value)) {
+    ASSERT(value.IsSmi());
+    intptr_t number = Smi::Cast(value).Value();
+    if (number < instr->from() || instr->to() < number) {

[Vyacheslav Egorov (Google), 2017/06/28 13:53:47]

maybe better:

bool result = instr->from() <= number && number < instr->to();
if (instr->is_negated()) { result = !result; }

SetValue(instr, Bool::Get(result));

[erikcorry, 2017/07/03 08:59:55]

Done, but with <= because to() is inclusive.

+      SetValue(instr, Bool::Get(instr->is_negated()));
+    } else {
+      SetValue(instr, Bool::Get(!instr->is_negated()));
+    }
+  } else if (IsNonConstant(value)) {
+    SetValue(instr, non_constant_);
+  }
+}
+
+
 void ConstantPropagator::VisitStrictCompare(StrictCompareInstr* instr) {
   Definition* left_defn = instr->left()->definition();
   Definition* right_defn = instr->right()->definition();
 
   Definition* unwrapped_left_defn = UnwrapPhi(left_defn);
   Definition* unwrapped_right_defn = UnwrapPhi(right_defn);
   if (unwrapped_left_defn == unwrapped_right_defn) {
     // Fold x === x, and x !== x to true/false.
     SetValue(instr, Bool::Get(instr->kind() == Token::kEQ_STRICT));
     if (unwrapped_left_defn != left_defn) {
@@ skipping 1290 matching lines @@
   GrowableArray<BitVector*> dominance_frontier;
   graph_->ComputeDominators(&dominance_frontier);
 
   if (FLAG_trace_constant_propagation &&
       FlowGraphPrinter::ShouldPrint(graph_->function())) {
     FlowGraphPrinter::PrintGraph("After CP", graph_);
   }
 }
 
 }  // namespace dart