Implement local load/store elimination on basic blocks.

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 243 matching lines @@
 DEFINE_bool(collect_megamorphic_maps_from_stub_cache,
             true,
             "crankshaft harvests type feedback from stub cache")
 DEFINE_bool(hydrogen_stats, false, "print statistics for hydrogen")
 DEFINE_bool(trace_hydrogen, false, "trace generated hydrogen to file")
 DEFINE_string(trace_hydrogen_filter, "*", "hydrogen tracing filter")
 DEFINE_bool(trace_hydrogen_stubs, false, "trace generated hydrogen for stubs")
 DEFINE_string(trace_hydrogen_file, NULL, "trace hydrogen to given file name")
 DEFINE_string(trace_phase, "HLZ", "trace generated IR for specified phases")
 DEFINE_bool(trace_inlining, false, "trace inlining decisions")
+DEFINE_bool(trace_load_elimination, false, "trace load elimination")
 DEFINE_bool(trace_alloc, false, "trace register allocator")
 DEFINE_bool(trace_all_uses, false, "trace all use positions")
 DEFINE_bool(trace_range, false, "trace range analysis")
 DEFINE_bool(trace_gvn, false, "trace global value numbering")
 DEFINE_bool(trace_representation, false, "trace representation types")
 DEFINE_bool(trace_escape_analysis, false, "trace hydrogen escape analysis")
 DEFINE_bool(trace_allocation_folding, false, "trace allocation folding")
 DEFINE_bool(trace_track_allocation_sites, false,
             "trace the tracking of allocation sites")
 DEFINE_bool(trace_migration, false, "trace object migration")
@@ skipping 14 matching lines @@
 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(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, false, "use load elimination")
 DEFINE_bool(dead_code_elimination, true, "use dead code elimination")
 DEFINE_bool(fold_constants, true, "use constant folding")
 DEFINE_bool(trace_dead_code_elimination, false, "trace dead code elimination")
 DEFINE_bool(unreachable_code_elimination, false,
             "eliminate unreachable code (hidden behind soft deopts)")
 DEFINE_bool(track_allocation_sites, true,
             "Use allocation site info to reduce transitions")
 DEFINE_bool(trace_osr, false, "trace on-stack replacement")
 DEFINE_int(stress_runs, 0, "number of stress runs")
 DEFINE_bool(optimize_closures, true, "optimize closures")
@@ skipping 535 matching lines @@
 #undef DEFINE_ALIAS_int
 #undef DEFINE_ALIAS_string
 #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