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

runtime/vm/intermediate_language.cc

Index: runtime/vm/intermediate_language.cc
diff --git a/runtime/vm/intermediate_language.cc b/runtime/vm/intermediate_language.cc
index 7b8e997150c84ea4da8d6cf68d74312d98a54121..f5f304592189ac2ed7f6f00335e1b0ee6b61e83d 100644
--- a/runtime/vm/intermediate_language.cc
+++ b/runtime/vm/intermediate_language.cc
@@ -1837,6 +1837,19 @@ Instruction* BranchInstr::Canonicalize(FlowGraphOptimizer* optimizer) {
         Value* operand = comp->InputAt(i);
         operand->set_instruction(this);
       }
+
+      // If comparison has an environment then steal it.
+      ASSERT(env() == NULL);  // StrictCompare can't deoptimize.
+      if (comp->env() != NULL) {
+        set_env(comp->env());
+        comp->set_env(NULL);

[Florian Schneider, 2013/02/13 11:22:11]

You may also need to set a new deopt id on the environment for consistency:

env()->set_deopt_id(deopt_id())

+
+        for (Environment::DeepIterator it(env()); !it.Done(); it.Advance()) {
+          Value* value = it.CurrentValue();
+          value->set_instruction(this);
+        }
+      }
+
       if (FLAG_trace_optimization) {
         OS::Print("Merging comparison v%"Pd"\n", comp->ssa_temp_index());
       }