When canonicalizing branch on StrictCompare ensure that branch gets correct environment.

runtime/vm/intermediate_language.cc

 // Copyright (c) 2013, 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/intermediate_language.h"
 
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 1803 matching lines @@
   return this;
 }
 
 
 Instruction* BranchInstr::Canonicalize(FlowGraphOptimizer* optimizer) {
   // Only handle strict-compares.
   if (comparison()->IsStrictCompare()) {
     Definition* replacement = comparison()->Canonicalize(optimizer);
     if (replacement == comparison() || replacement == NULL) return this;
     ComparisonInstr* comp = replacement->AsComparison();
-    if (comp == NULL) return this;
+    if ((comp == NULL) || comp->CanDeoptimize()) return this;
+
+    // Check that comparison is not serving as a pending deoptimization target
+    // for conversions.
+    for (intptr_t i = 0; i < comp->InputCount(); i++) {
+      if (comp->RequiredInputRepresentation(i) !=
+          comp->InputAt(i)->definition()->representation()) {
+        return this;
+      }
+    }
 
     // Replace the comparison if the replacement is used at this branch,
     // and has exactly one use.
     if ((comp->input_use_list()->instruction() == this) &&
         (comp->input_use_list()->next_use() == NULL) &&
         (comp->env_use_list() == NULL)) {
       comp->RemoveFromGraph();
       // It is safe to pass a NULL iterator because we're replacing the
       // comparison wrapped in a BranchInstr which does not modify the
       // linked list of instructions.
@@ skipping 1033 matching lines @@
     default:
       UNREACHABLE();
   }
   return kPowRuntimeEntry;
 }
 
 
 #undef __
 
 }  // namespace dart