Revert "Fold HTypeInfoReadVariable of instance creation."

pkg/compiler/lib/src/ssa/optimize.dart

Index: pkg/compiler/lib/src/ssa/optimize.dart
diff --git a/pkg/compiler/lib/src/ssa/optimize.dart b/pkg/compiler/lib/src/ssa/optimize.dart
index 4700112b3211ec528f9b1bd3194091f8c985be00..031922228f881912a882b621935a64d4a3312644 100644
--- a/pkg/compiler/lib/src/ssa/optimize.dart
+++ b/pkg/compiler/lib/src/ssa/optimize.dart
@@ -1057,34 +1057,6 @@ class SsaInstructionSimplifier extends HBaseVisitor
       return node;
     }
 
-    /// Read the type variable from an allocation of type [createdClass], where
-    /// [selectTypeArgumentFromObjectCreation] extracts the type argument from
-    /// the allocation for factory constructor call.
-    HInstruction finishSubstituted(ClassElement createdClass,
-        HInstruction selectTypeArgumentFromObjectCreation(int index)) {
-      HInstruction instructionForTypeVariable(TypeVariableType tv) {
-        return selectTypeArgumentFromObjectCreation(
-            createdClass.thisType.typeArguments.indexOf(tv));
-      }
-
-      DartType type = createdClass.thisType
-          .asInstanceOf(variable.element.enclosingClass)
-          .typeArguments[variable.element.index];
-      if (type is TypeVariableType) {
-        return instructionForTypeVariable(type);
-      }
-      List<HInstruction> arguments = <HInstruction>[];
-      type.forEachTypeVariable((v) {
-        arguments.add(instructionForTypeVariable(v));
-      });
-      HInstruction replacement = new HTypeInfoExpression(
-          TypeInfoExpressionKind.COMPLETE,
-          type,
-          arguments,
-          backend.dynamicType);
-      return replacement;
-    }
-
     // Type variable evaluated in the context of a constant can be replaced with
     // a ground term type.
     if (object is HConstant) {
@@ -1095,42 +1067,10 @@ class SsaInstructionSimplifier extends HBaseVisitor
       return node;
     }
 
-    // Look for an allocation with type information and re-write type variable
-    // as a function of the type parameters of the allocation.  This effectively
-    // store-forwards a type variable read through an allocation.
-
-    // Match:
-    //
-    //     setRuntimeTypeInfo(
-    //         HForeignNew(ClassElement),
-    //         HTypeInfoExpression(t_0, t_1, t_2, ...));
-    //
-    // The `t_i` are the values of the type parameters of ClassElement.
-    if (object is HInvokeStatic) {
-      if (object.element == helpers.setRuntimeTypeInfo) {
-        HInstruction allocation = object.inputs[0];
-        if (allocation is HForeignNew) {
-          HInstruction typeInfo = object.inputs[1];
-          if (typeInfo is HTypeInfoExpression) {
-            return finishSubstituted(
-                allocation.element, (int index) => typeInfo.inputs[index]);
-          }
-        }
-        return node;
-      }
-      // TODO(sra): Factory constructors pass type arguments after the value
-      // arguments. The [select] argument indexes into these type arguments.
-    }
-
-    // Non-generic type (which extends or mixes in a generic type, for example
-    // CodeUnits extends UnmodifiableListBase<int>).
-    // Also used for raw-type when the type parameters are elided.
-    if (object is HForeignNew) {
-      return finishSubstituted(
-          object.element,
-          // If there are type arguments, all type arguments are 'dynamic'.
-          (int i) => graph.addConstantNull(compiler));
-    }
+    // TODO(sra): HTypeInfoReadVariable on an instance creation can be replaced
+    // with an input of the instance creation's HTypeInfoExpression (or a
+    // HTypeInfoExpression of an input).  This would in effect store-forward the
+    // type parameters.
 
     return node;
   }