Added a simple dead code removal phase.

tools/run-tests.py

 #!/usr/bin/env python
 #
 # Copyright 2012 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
@@ skipping 38 matching lines @@
 DEFAULT_TESTS = ["mjsunit", "cctest", "message", "preparser"]
 TIMEOUT_DEFAULT = 60
 TIMEOUT_SCALEFACTOR = {"debug"   : 4,
                        "release" : 1 }
 
 # Use this to run several variants of the tests.
 VARIANT_FLAGS = [[],
                  ["--stress-opt", "--always-opt"],
                  ["--nocrankshaft"]]
 MODE_FLAGS = {
-    "debug"   : ["--nobreak-on-abort", "--enable-slow-asserts",
-                 "--debug-code", "--verify-heap"],
-    "release" : ["--nobreak-on-abort"]}
+    "debug"   : ["--nobreak-on-abort", "--nodead-code-elimination",
+                 "--enable-slow-asserts", "--debug-code", "--verify-heap"],
+    "release" : ["--nobreak-on-abort", "--nodead-code-elimination"]}
 
 
 def BuildOptions():
   result = optparse.OptionParser()
   result.add_option("--arch",
                     help=("The architecture to run tests for, "
                           "'auto' or 'native' for auto-detect"),
                     default="ia32,x64,arm")
   result.add_option("--arch-and-mode",
                     help="Architecture and mode in the format 'arch.mode'",
@@ skipping 274 matching lines @@
   except KeyboardInterrupt:
     return 1
 
   if options.time:
     verbose.PrintTestDurations(suites, overall_duration)
   return exit_code
 
 
 if __name__ == "__main__":
   sys.exit(Main())