Fix maybe_string_add for adds that have no type feedback where --always-opt is on.

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/hydrogen.h"
 
 #include <sstream>
 
 #include "src/v8.h"
 
@@ skipping 10380 matching lines @@
   bool maybe_string_add = op == Token::ADD &&
                           (left_type->Maybe(Type::String()) ||
                            left_type->Maybe(Type::Receiver()) ||
                            right_type->Maybe(Type::String()) ||
                            right_type->Maybe(Type::Receiver()));
 
   if (!left_type->IsInhabited()) {
     Add<HDeoptimize>(
         Deoptimizer::kInsufficientTypeFeedbackForLHSOfBinaryOperation,
         Deoptimizer::SOFT);
-    // TODO(rossberg): we should be able to get rid of non-continuous
-    // defaults.
     left_type = Type::Any(zone());
-  } else {
-    if (!maybe_string_add) left = TruncateToNumber(left, &left_type);
     left_rep = Representation::FromType(left_type);
+    maybe_string_add = op == Token::ADD;
   }
 
   if (!right_type->IsInhabited()) {
     Add<HDeoptimize>(
         Deoptimizer::kInsufficientTypeFeedbackForRHSOfBinaryOperation,
         Deoptimizer::SOFT);
     right_type = Type::Any(zone());
-  } else {
-    if (!maybe_string_add) right = TruncateToNumber(right, &right_type);
     right_rep = Representation::FromType(right_type);
+    maybe_string_add = op == Token::ADD;
+  }
+
+  if (!maybe_string_add) {
+    left = TruncateToNumber(left, &left_type);
+    right = TruncateToNumber(right, &right_type);
   }
 
   // Special case for string addition here.
   if (op == Token::ADD &&
       (left_type->Is(Type::String()) || right_type->Is(Type::String()))) {
     // Validate type feedback for left argument.
     if (left_type->Is(Type::String())) {
       left = BuildCheckString(left);
     }
 
@@ skipping 2494 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal