Add an optional parameter to the dominatedUsers function in case we want to analyze the whole block,

lib/compiler/implementation/ssa/nodes.dart

 // Copyright (c) 2012, 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.
 
 interface HVisitor<R> {
   R visitAdd(HAdd node);
   R visitBailoutTarget(HBailoutTarget node);
   R visitBitAnd(HBitAnd node);
   R visitBitNot(HBitNot node);
   R visitBitOr(HBitOr node);
@@ skipping 914 matching lines @@
       if (oldInputUsers[i] == this) {
         oldInputUsers[i] = oldInputUsers[oldInput.usedBy.length - 1];
         oldInputUsers.length--;
       } else {
         i++;
       }
     }
   }
 
   // Compute the set of users of this instruction that is dominated by
-  // [other].
+  // [other]. If [other] is a user of [this], it is included in the
+  // returned set.
   Set<HInstruction> dominatedUsers(HInstruction other) {
     // Keep track of all instructions that we have to deal with later
     // and count the number of them that are in the current block.
     Set<HInstruction> users = new Set<HInstruction>();
     int usersInCurrentBlock = 0;
 
     // Run through all the users and see if they are dominated or
     // potentially dominated by [other].
     HBasicBlock otherBlock = other.block;
     for (int i = 0, length = usedBy.length; i < length; i++) {
       HInstruction current = usedBy[i];
-      if (current !== other && otherBlock.dominates(current.block)) {
+      if (otherBlock.dominates(current.block)) {
         if (current.block === otherBlock) usersInCurrentBlock++;
         users.add(current);
       }
     }
 
     // Run through all the phis in the same block as [other] and remove them
     // from the users set.
     if (usersInCurrentBlock > 0) {
       for (HPhi phi = otherBlock.phis.first; phi !== null; phi = phi.next) {
         if (users.contains(phi)) {
@@ skipping 1784 matching lines @@
   HBasicBlock get start() => expression.start;
   HBasicBlock get end() {
     // We don't create a switch block if there are no cases.
     assert(!statements.isEmpty());
     return statements.last().end;
   }
 
   bool accept(HStatementInformationVisitor visitor) =>
       visitor.visitSwitchInfo(this);
 }