Fix bug in optimized compiler's switch-statement.

src/hydrogen.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2517 matching lines @@
   HBasicBlock* curr_test_block = first_test_block;
   HBasicBlock* fall_through_block = NULL;
   BreakAndContinueInfo break_info(stmt);
   { BreakAndContinueScope push(&break_info, this);
     for (int i = 0; i < clause_count; ++i) {
       CaseClause* clause = clauses->at(i);
 
       // Identify the block where normal (non-fall-through) control flow
       // goes to.
       HBasicBlock* normal_block = NULL;
-      if (clause->is_default() && last_block != NULL) {
-        normal_block = last_block;
-        last_block = NULL;  // Cleared to indicate we've handled it.
+      if (clause->is_default()) {
+        if (last_block != NULL) {
+          normal_block = last_block;
+          last_block = NULL;  // Cleared to indicate we've handled it.
+        }
       } else if (!curr_test_block->end()->IsDeoptimize()) {
         normal_block = curr_test_block->end()->FirstSuccessor();
         curr_test_block = curr_test_block->end()->SecondSuccessor();
       }
 
       // Identify a block to emit the body into.
       if (normal_block == NULL) {
         if (fall_through_block == NULL) {
           // (a) Unreachable.
           if (clause->is_default()) {
@@ skipping 3591 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal