First implementation of store elimination.

src/flag-definitions.h

Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index 658991ff5425159f857bf9d31c123a40f90ae2e9..c1ee4c3bc712f380d96f03c707725d1f895c1e78 100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -264,6 +264,7 @@ 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(trace_alloc, false, "trace register allocator")
 DEFINE_bool(trace_all_uses, false, "trace all use positions")
 DEFINE_bool(trace_range, false, "trace range analysis")
@@ -297,6 +298,7 @@ DEFINE_bool(array_index_dehoisting, true,
 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(store_elimination, true, "use store elimination")
 DEFINE_bool(check_elimination, false, "use check elimination")
 DEFINE_bool(dead_code_elimination, true, "use dead code elimination")
 DEFINE_bool(fold_constants, true, "use constant folding")