Extract interceptor calls from raw is-checks.

sdk/lib/_internal/compiler/implementation/ssa/nodes.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/nodes.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/nodes.dart b/sdk/lib/_internal/compiler/implementation/ssa/nodes.dart
index a5110bbe6c7d979fb9511d28bdff48d572df734d..ab9121e00c45793055b93e23b1a63f01da06746c 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/nodes.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/nodes.dart
@@ -2209,11 +2209,29 @@ class HIs extends HInstruction {
   static const int VARIABLE_CHECK = 2;
 
   final DartType typeExpression;
-  final bool nullOk;
   final int kind;
 
-  HIs(this.typeExpression, List<HInstruction> inputs, this.kind,
-      {this.nullOk: false}) : super(inputs) {
+  HIs.direct(DartType typeExpression,
+             HInstruction expression)
+      : this.internal(typeExpression, [expression], RAW_CHECK);
+
+  HIs.raw(DartType typeExpression,
+          HInstruction expression,
+          HInterceptor interceptor)
+      : this.internal(typeExpression, [expression, interceptor], RAW_CHECK);
+
+  HIs.compound(DartType typeExpression,
+               HInstruction expression,
+               HInstruction call)
+      : this.internal(typeExpression, [expression, call], COMPOUND_CHECK);
+
+  HIs.variable(DartType typeExpression,
+               HInstruction expression,
+               HInstruction call)
+      : this.internal(typeExpression, [expression, call], VARIABLE_CHECK);
+
+  HIs.internal(this.typeExpression, List<HInstruction> inputs, this.kind)
+      : super(inputs) {
     assert(kind >= RAW_CHECK && kind <= VARIABLE_CHECK);
     setUseGvn();
     instructionType = HType.BOOLEAN;
@@ -2221,6 +2239,11 @@ class HIs extends HInstruction {
 
   HInstruction get expression => inputs[0];
 
+  HInstruction get interceptor {
+    assert(kind == RAW_CHECK);
+    return inputs.length > 1 ? inputs[1] : null;
+  }
+
   HInstruction get checkCall {
     assert(kind == VARIABLE_CHECK || kind == COMPOUND_CHECK);
     return inputs[1];
@@ -2240,7 +2263,6 @@ class HIs extends HInstruction {
 
   bool dataEquals(HIs other) {
     return typeExpression == other.typeExpression
-        && nullOk == other.nullOk
         && kind == other.kind;
   }
 }