Use BitVector instead of handcrafted SparseSet.

src/hydrogen-gvn.cc

Index: src/hydrogen-gvn.cc
diff --git a/src/hydrogen-gvn.cc b/src/hydrogen-gvn.cc
index 10826a6023f22a8186cbce7a7c6af2266157c7ce..65c5c3a77b559b7d2152701b8a84f0d4d649898e 100644
--- a/src/hydrogen-gvn.cc
+++ b/src/hydrogen-gvn.cc
@@ -368,7 +368,7 @@ HGlobalValueNumberingPhase::HGlobalValueNumberingPhase(HGraph* graph)
         removed_side_effects_(false),
         block_side_effects_(graph->blocks()->length(), zone()),
         loop_side_effects_(graph->blocks()->length(), zone()),
-        visited_on_paths_(zone(), graph->blocks()->length()) {
+        visited_on_paths_(graph->blocks()->length(), zone()) {
     ASSERT(!AllowHandleAllocation::IsAllowed());
     block_side_effects_.AddBlock(GVNFlagSet(), graph->blocks()->length(),
                                  zone());
@@ -621,7 +621,8 @@ HGlobalValueNumberingPhase::CollectSideEffectsOnPathsToDominatedBlock(
     HBasicBlock* block = dominated->predecessors()->at(i);
     if (dominator->block_id() < block->block_id() &&
         block->block_id() < dominated->block_id() &&
-        visited_on_paths_.Add(block->block_id())) {
+        !visited_on_paths_.Contains(block->block_id())) {
+      visited_on_paths_.Add(block->block_id());
       side_effects.Add(block_side_effects_[block->block_id()]);
       if (block->IsLoopHeader()) {
         side_effects.Add(loop_side_effects_[block->block_id()]);