Improve precision of range analysis by allowing it to track ranges across all int typed phis.

runtime/vm/flow_graph_range_analysis.h

 // Copyright (c) 2014, 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.
 
 #ifndef VM_FLOW_GRAPH_RANGE_ANALYSIS_H_
 #define VM_FLOW_GRAPH_RANGE_ANALYSIS_H_
 
 #include "vm/flow_graph.h"
 #include "vm/intermediate_language.h"
 
@@ skipping 484 matching lines @@
     return !Range::IsUnknown(range) && range->IsPositive();
   }
 };
 
 
 // Range analysis for integer values.
 class RangeAnalysis : public ValueObject {
  public:
   explicit RangeAnalysis(FlowGraph* flow_graph)
       : flow_graph_(flow_graph),
-        smi_range_(Range::Full(RangeBoundary::kRangeBoundarySmi)) { }
+        smi_range_(Range::Full(RangeBoundary::kRangeBoundarySmi)),
+        int64_range_(Range::Full(RangeBoundary::kRangeBoundaryInt64)) { }
 
   // Infer ranges for all values and remove overflow checks from binary smi
   // operations when proven redundant.
   void Analyze();
 
   // Helper that should be used to access ranges of inputs during range
   // inference.
-  // Returns meaningful results for uses of non-smi definitions that have smi
-  // as a reaching type.
+  // Returns meaningful results for uses of non-smi/non-int definitions that
+  // have smi/int as a reaching type.
+  // For Int typed definitions we use full Int64 range as a safe approximation
+  // even though they might contain Bigint values because we only support
+  // 64-bit operations in the optimized code - which means that Bigint will
+  // cause deoptimization.
   const Range* GetSmiRange(Value* value) const;
+  const Range* GetIntRange(Value* value) const;
 
   static bool IsIntegerDefinition(Definition* defn) {
-    return (defn->Type()->ToCid() == kSmiCid) ||
-        defn->IsMintDefinition() ||
-        defn->IsInt32Definition();
+    return defn->Type()->IsInt();
   }
 
   void AssignRangesRecursively(Definition* defn);
 
  private:
   enum JoinOperator {
     NONE,
     WIDEN,
     NARROW
   };
@@ skipping 59 matching lines @@
 
   Range* ConstraintSmiRange(Token::Kind op, Definition* boundary);
 
   Isolate* isolate() const { return flow_graph_->isolate(); }
 
   FlowGraph* flow_graph_;
 
   // Range object representing full Smi range.
   Range smi_range_;
 
+  Range int64_range_;
+
   // Value that are known to be smi or mint.
   GrowableArray<Definition*> values_;
 
   GrowableArray<BinaryMintOpInstr*> binary_mint_ops_;
 
   GrowableArray<ShiftMintOpInstr*> shift_mint_ops_;
 
   // All CheckArrayBound instructions.
   GrowableArray<CheckArrayBoundInstr*> bounds_checks_;
 
@@ skipping 34 matching lines @@
   BitVector* selected_uint32_defs_;
 
   FlowGraph* flow_graph_;
   Isolate* isolate_;
 };
 
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_RANGE_ANALYSIS_H_