Eliminatable CheckMaps replaced with if(true) or if(false).

src/hydrogen-flow-engine.h

Index: src/hydrogen-flow-engine.h
diff --git a/src/hydrogen-flow-engine.h b/src/hydrogen-flow-engine.h
index 4e1275546f611e2401e467484976f73d59b3e784..24d912a190e662cccdc3734cabb1d93134ec0d07 100644
--- a/src/hydrogen-flow-engine.h
+++ b/src/hydrogen-flow-engine.h
@@ -142,7 +142,10 @@ class HFlowEngine {
       for (int i = 0; i < max; i++) {
         HBasicBlock* succ = block->end()->SuccessorAt(i);
         IncrementPredecessorCount(succ);
-        if (StateAt(succ) == NULL) {
+        if (succ->IsUnreachable()) {
+          // Unreachable blocks do not modify state of predecessor.
+          SetStateAt(succ, state);
+        } else if (StateAt(succ) == NULL) {
           // This is the first state to reach the successor.
           if (max == 1 && succ->predecessors()->length() == 1) {
             // Optimization: successor can inherit this state.