Turn on crankshaft as the default for X64 and ARM

src/flag-definitions.h

 // Copyright 2010 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 79 matching lines @@
 #define DEFINE_float(nam, def, cmt) FLAG(FLOAT, double, nam, def, cmt)
 #define DEFINE_string(nam, def, cmt) FLAG(STRING, const char*, nam, def, cmt)
 #define DEFINE_args(nam, def, cmt) FLAG(ARGS, JSArguments, nam, def, cmt)
 
 //
 // Flags in all modes.
 //
 #define FLAG FLAG_FULL
 
 // Flags for Crankshaft.
-#ifdef V8_TARGET_ARCH_IA32
 DEFINE_bool(crankshaft, true, "use crankshaft")
-#else
-DEFINE_bool(crankshaft, false, "use crankshaft")
-#endif
 DEFINE_string(hydrogen_filter, "", "hydrogen use/trace filter")
 DEFINE_bool(use_hydrogen, true, "use generated hydrogen for compilation")
 DEFINE_bool(build_lithium, true, "use lithium chunk builder")
 DEFINE_bool(alloc_lithium, true, "use lithium register allocator")
 DEFINE_bool(use_lithium, true, "use lithium code generator")
 DEFINE_bool(use_range, true, "use hydrogen range analysis")
 DEFINE_bool(eliminate_dead_phis, true, "eliminate dead phis")
 DEFINE_bool(use_gvn, true, "use hydrogen global value numbering")
 DEFINE_bool(use_canonicalizing, true, "use hydrogen instruction canonicalizing")
 DEFINE_bool(use_inlining, true, "use function inlining")
@@ skipping 428 matching lines @@
 #undef FLAG
 
 #undef DEFINE_bool
 #undef DEFINE_int
 #undef DEFINE_string
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META