Weaken a bogus assertion in use list verification.

runtime/vm/flow_graph.cc

 // 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.
 
 #include "vm/flow_graph.h"
 
 #include "vm/bit_vector.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/intermediate_language.h"
 #include "vm/longjump.h"
@@ skipping 113 matching lines @@
   return count;
 }
 
 
 static void VerifyUseListsInInstruction(Instruction* instr) {
   ASSERT(instr != NULL);
   ASSERT(!instr->IsJoinEntry());
   for (intptr_t i = 0; i < instr->InputCount(); ++i) {
     Value* use = instr->InputAt(i);
     ASSERT(use->definition() != NULL);
-    ASSERT(use->definition() != instr);
+    ASSERT((use->definition() != instr) || use->definition()->IsPhi());
     ASSERT(use->instruction() == instr);
     ASSERT(use->use_index() == i);
     ASSERT(!FLAG_verify_compiler ||
            (1 == MembershipCount(use, use->definition()->input_use_list())));
   }
   if (instr->env() != NULL) {
     intptr_t use_index = 0;
     for (Environment::DeepIterator it(instr->env()); !it.Done(); it.Advance()) {
       Value* use = it.CurrentValue();
       ASSERT(use->definition() != NULL);
-      ASSERT(use->definition() != instr);
+      ASSERT((use->definition() != instr) || use->definition()->IsPhi());
       ASSERT(use->instruction() == instr);
       ASSERT(use->use_index() == use_index++);
       ASSERT(!FLAG_verify_compiler ||
              (1 == MembershipCount(use, use->definition()->env_use_list())));
     }
   }
   Definition* defn = instr->AsDefinition();
   if (defn != NULL) {
     Value* prev = NULL;
     Value* curr = defn->input_use_list();
@@ skipping 544 matching lines @@
          !it.Done();
          it.Advance()) {
       ++size;
     }
   }
   return size;
 }
 
 
 }  // namespace dart