Use range information to omit checks in TRUNCDIV/MOD operations.

runtime/vm/intermediate_language.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/intermediate_language.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
@@ skipping 1096 matching lines @@
           || !right_range->IsWithin(0, RangeBoundary::kPlusInfinity);
     }
     case Token::kSHL: {
       Range* right_range = this->right()->definition()->range();
       if ((right_range != NULL) && is_truncating()) {
         // Can deoptimize if right can be negative.
         return !right_range->IsWithin(0, RangeBoundary::kPlusInfinity);
       }
       return true;
     }
+    case Token::kMOD: {
+      Range* right_range = this->right()->definition()->range();
+      return (right_range == NULL) || right_range->Overlaps(0, 0);
+    }
     default:
       return overflow_;
   }
 }
 
 
 bool BinarySmiOpInstr::RightIsPowerOfTwoConstant() const {
   if (!right()->definition()->IsConstant()) return false;
   const Object& constant = right()->definition()->AsConstant()->value();
   if (!constant.IsSmi()) return false;
@@ skipping 1552 matching lines @@
 
 
 // Inclusive.
 bool Range::IsWithin(intptr_t min_int, intptr_t max_int) const {
   if (min().LowerBound().value() < min_int) return false;
   if (max().UpperBound().value() > max_int) return false;
   return true;
 }
 
 
+bool Range::Overlaps(intptr_t min_int, intptr_t max_int) const {
+  const intptr_t this_min = min().LowerBound().value();
+  const intptr_t this_max = max().UpperBound().value();
+  if ((this_min <= min_int) && (min_int <= this_max)) return true;
+  if ((this_min <= max_int) && (max_int <= this_max)) return true;
+  if ((min_int < this_min) && (max_int > this_max)) return true;
+  return false;
+}
+
+
 bool Range::IsUnsatisfiable() const {
   // Constant case: For example [0, -1].
   if (Range::ConstantMin(this).value() > Range::ConstantMax(this).value()) {
     return true;
   }
   // Symbol case: For example [v+1, v].
   if (DependOnSameSymbol(min(), max()) && min().offset() > max().offset()) {
     return true;
   }
   return false;
@@ skipping 272 matching lines @@
     ASSERT((*inputs)[i] != NULL);
     (*inputs)[i]->set_instruction(this);
     (*inputs)[i]->set_use_index(i);
   }
   deopt_id_ = original_deopt_id;
 }
 
 #undef __
 
 }  // namespace dart