Fix dominatedUsers for phis.

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 945 matching lines @@
     // 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 (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)) {
+          users.remove(phi);
+          if (--usersInCurrentBlock == 0) break;
+        }
+      }
+    }
+
     // Run through all the instructions before [other] and remove them
     // from the users set.
     if (usersInCurrentBlock > 0) {
       HInstruction current = otherBlock.first;
       while (current !== other) {
         if (users.contains(current)) {
           users.remove(current);
           if (--usersInCurrentBlock == 0) break;
         }
         current = current.next;
@@ skipping 1707 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);
 }