Use the new introduced block's reachable flag.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index e16bb22957f8a6149c7075361ee2dbc0ee284eb9..31630d14118a3c617d1b28a801863f5574fc92e8 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -4037,7 +4037,7 @@ Representation HValue::RepresentationFromUseRequirements() {
   Representation rep = Representation::None();
   for (HUseIterator it(uses()); !it.Done(); it.Advance()) {
     // Ignore the use requirement from never run code
-    if (it.value()->block()->IsDeoptimizing()) continue;
+    if (it.value()->block()->IsUnreachable()) continue;
 
     // We check for observed_input_representation elsewhere.
     Representation use_rep =