Use same range info when emitting code and computing if instruction can deopt.

runtime/vm/flow_graph_range_analysis.cc

Index: runtime/vm/flow_graph_range_analysis.cc
diff --git a/runtime/vm/flow_graph_range_analysis.cc b/runtime/vm/flow_graph_range_analysis.cc
index ba9360352aa6ada659c7343fdff0a1dc3a6949ef..808ecc7cc92a53b2cdbf33dd56451bb49a306a24 100644
--- a/runtime/vm/flow_graph_range_analysis.cc
+++ b/runtime/vm/flow_graph_range_analysis.cc
@@ -2256,6 +2256,12 @@ void Range::Clamp(RangeBoundary::RangeSize size) {
 }
 
 
+void Range::ClampToConstant(RangeBoundary::RangeSize size) {
+  min_ = min_.LowerBound().Clamp(size);
+  max_ = max_.UpperBound().Clamp(size);
+}
+
+
 void Range::Shl(const Range* left,
                 const Range* right,
                 RangeBoundary* result_min,
@@ -2886,10 +2892,28 @@ void BinaryIntegerOpInstr::InferRangeHelper(const Range* left_range,
 }
 
 
+static void CacheRange(Range** slot,
+                       const Range* range,

[rmacnak, 2017/05/18 20:02:45]

I see crashes in some tests because range may be null via
ShiftMintOpInstr::InferRange. Presumably this should start with

if (range == NULL) {
  *slot = NULL;
  return;
}

[Vyacheslav Egorov (Google), 2017/05/19 08:07:08]

Ooops. Should have rerun tests after refactoring.

+                       RangeBoundary::RangeSize size) {
+  if (*slot == NULL) {
+    *slot = new Range();
+  }
+  **slot = *range;
+
+  // Eliminate any symbolic dependencies from the range information.
+  (*slot)->ClampToConstant(size);
+}
+
+
 void BinarySmiOpInstr::InferRange(RangeAnalysis* analysis, Range* range) {
+  const Range* right_smi_range = analysis->GetSmiRange(right());
   // TODO(vegorov) completely remove this once GetSmiRange is eliminated.
-  InferRangeHelper(analysis->GetSmiRange(left()),
-                   analysis->GetSmiRange(right()), range);
+  if (op_kind() == Token::kSHR || op_kind() == Token::kSHL ||
+      op_kind() == Token::kMOD || op_kind() == Token::kTRUNCDIV) {
+    CacheRange(&right_range_, right_smi_range,
+               RangeBoundary::kRangeBoundarySmi);
+  }
+  InferRangeHelper(analysis->GetSmiRange(left()), right_smi_range, range);
 }
 
 
@@ -2906,6 +2930,8 @@ void BinaryMintOpInstr::InferRange(RangeAnalysis* analysis, Range* range) {
 
 
 void ShiftMintOpInstr::InferRange(RangeAnalysis* analysis, Range* range) {
+  CacheRange(&shift_range_, right()->definition()->range(),
+             RangeBoundary::kRangeBoundaryInt64);
   InferRangeHelper(left()->definition()->range(),
                    right()->definition()->range(), range);
 }