[turbofan] Improve the store-store elimination.

src/flag-definitions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file defines all of the flags.  It is separated into different section,
 // for Debug, Release, Logging and Profiling, etc.  To add a new flag, find the
 // correct section, and use one of the DEFINE_ macros, without a trailing ';'.
 //
 // This include does not have a guard, because it is a template-style include,
 // which can be included multiple times in different modes.  It expects to have
@@ skipping 336 matching lines @@
 DEFINE_BOOL(trace_environment_liveness, false,
             "trace liveness of local variable slots")
 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_store_elimination, false, "trace store elimination")
+DEFINE_BOOL(turbo_verify_store_elimination, false,
+            "verify store elimination more rigorously")
 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_removable_simulates, false, "trace removable simulates")
 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")
@@ skipping 49 matching lines @@
 DEFINE_BOOL(block_concurrent_recompilation, false,
             "block queued jobs until released")
 
 DEFINE_BOOL(omit_map_checks_for_leaf_maps, true,
             "do not emit check maps for constant values that have a leaf map, "
             "deoptimize the optimized code if the layout of the maps changes.")
 
 // Flags for TurboFan.
 DEFINE_BOOL(turbo, false, "enable TurboFan compiler")
 DEFINE_IMPLICATION(turbo, turbo_asm_deoptimization)
-DEFINE_IMPLICATION(turbo, turbo_store_elimination)
 DEFINE_IMPLICATION(turbo, turbo_loop_peeling)
 DEFINE_BOOL(turbo_shipping, true, "enable TurboFan compiler on subset")
 DEFINE_BOOL(turbo_from_bytecode, false, "enable building graphs from bytecode")
 DEFINE_BOOL(turbo_sp_frame_access, false,
             "use stack pointer-relative access to frame wherever possible")
 DEFINE_BOOL(turbo_preprocess_ranges, true,
             "run pre-register allocation heuristics")
 DEFINE_BOOL(turbo_loop_stackcheck, true, "enable stack checks in loops")
 DEFINE_STRING(turbo_filter, "~~", "optimization filter for TurboFan compiler")
 DEFINE_BOOL(trace_turbo, false, "trace generated TurboFan IR")
@@ skipping 40 matching lines @@
 DEFINE_BOOL(turbo_loop_peeling, false, "Turbofan loop peeling")
 DEFINE_BOOL(turbo_cf_optimization, true, "optimize control flow in TurboFan")
 DEFINE_BOOL(turbo_frame_elision, true, "elide frames in TurboFan")
 DEFINE_BOOL(turbo_cache_shared_code, true, "cache context-independent code")
 DEFINE_BOOL(turbo_preserve_shared_code, false, "keep context-independent code")
 DEFINE_BOOL(turbo_escape, false, "enable escape analysis")
 DEFINE_BOOL(turbo_instruction_scheduling, false,
             "enable instruction scheduling in TurboFan")
 DEFINE_BOOL(turbo_stress_instruction_scheduling, false,
             "randomly schedule instructions to stress dependency tracking")
-DEFINE_BOOL(turbo_store_elimination, false,
+DEFINE_BOOL(turbo_store_elimination, true,
             "enable store-store elimination in TurboFan")
 
 // Flags for native WebAssembly.
 DEFINE_BOOL(expose_wasm, false, "expose WASM interface to JavaScript")
 DEFINE_INT(wasm_num_compilation_tasks, 10,
            "number of parallel compilation tasks for wasm")
 DEFINE_BOOL(trace_wasm_encoder, false, "trace encoding of wasm code")
 DEFINE_BOOL(trace_wasm_decoder, false, "trace decoding of wasm code")
 DEFINE_BOOL(trace_wasm_decode_time, false, "trace decoding time of wasm code")
 DEFINE_BOOL(trace_wasm_compiler, false, "trace compiling of wasm code")
@@ skipping 702 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