Add FLAG_trace_bce

src/flag-definitions.h

 // 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
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 284 matching lines @@
            "deoptimize every n garbage collections")
 DEFINE_bool(print_deopt_stress, false, "print number of possible deopt points")
 DEFINE_bool(trap_on_deopt, false, "put a break point before deoptimizing")
 DEFINE_bool(trap_on_stub_deopt, false,
             "put a break point before deoptimizing a stub")
 DEFINE_bool(deoptimize_uncommon_cases, true, "deoptimize uncommon cases")
 DEFINE_bool(polymorphic_inlining, true, "polymorphic inlining")
 DEFINE_bool(use_osr, true, "use on-stack replacement")
 DEFINE_bool(array_bounds_checks_elimination, true,
             "perform array bounds checks elimination")
+DEFINE_bool(trace_bce, false, "trace array bounds check elimination")
 DEFINE_bool(array_bounds_checks_hoisting, false,
             "perform array bounds checks hoisting")
 DEFINE_bool(array_index_dehoisting, true,
             "perform array index dehoisting")
 DEFINE_bool(analyze_environment_liveness, true,
             "analyze liveness of environment slots and zap dead values")
 DEFINE_bool(load_elimination, true, "use load elimination")
 DEFINE_bool(check_elimination, true, "use check elimination")
 DEFINE_bool(dead_code_elimination, true, "use dead code elimination")
 DEFINE_bool(fold_constants, true, "use constant folding")
@@ skipping 603 matching lines @@
 #undef DEFINE_ALIAS_float
 #undef DEFINE_ALIAS_args
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS
 
 #undef COMMA