Optimizing: Speed up HEnvironment use removal

Removal of use records from HEnvironment vregs involved iterating over
potentially large linked lists which made compilation of huge methods
very slow. This patch turns use lists into doubly-linked lists, stores
pointers to the relevant nodes inside HEnvironment and subsequently
turns the removals into constant-time operations.

Change-Id: I0e1d4d782fd624e7b8075af75d4adf0a0634a1ee

1 files changed, 9 insertions, 9 deletions

diff --git a/compiler/optimizing/ssa_phi_elimination.cc b/compiler/optimizing/ssa_phi_elimination.cc
index 58cea771b9..fd30c1bc76 100644
--- a/compiler/optimizing/ssa_phi_elimination.cc
+++ b/compiler/optimizing/ssa_phi_elimination.cc
@@ -26,8 +26,8 @@ void SsaDeadPhiElimination::Run() {
       HPhi* phi = inst_it.Current()->AsPhi();
       // Set dead ahead of running through uses. The phi may have no use.
       phi->SetDead();
-      for (HUseIterator<HInstruction> use_it(phi->GetUses()); !use_it.Done(); use_it.Advance()) {
-        HUseListNode<HInstruction>* current = use_it.Current();
+      for (HUseIterator<HInstruction*> use_it(phi->GetUses()); !use_it.Done(); use_it.Advance()) {
+        HUseListNode<HInstruction*>* current = use_it.Current();
         HInstruction* user = current->GetUser();
         if (!user->IsPhi()) {
           worklist_.Add(phi);
@@ -61,9 +61,9 @@ void SsaDeadPhiElimination::Run() {
       next = current->GetNext();
       if (current->AsPhi()->IsDead()) {
         if (current->HasUses()) {
-          for (HUseIterator<HInstruction> use_it(current->GetUses()); !use_it.Done();
+          for (HUseIterator<HInstruction*> use_it(current->GetUses()); !use_it.Done();
                use_it.Advance()) {
-            HUseListNode<HInstruction>* user_node = use_it.Current();
+            HUseListNode<HInstruction*>* user_node = use_it.Current();
             HInstruction* user = user_node->GetUser();
             DCHECK(user->IsLoopHeaderPhi()) << user->GetId();
             DCHECK(user->AsPhi()->IsDead()) << user->GetId();
@@ -73,12 +73,12 @@ void SsaDeadPhiElimination::Run() {
           }
         }
         if (current->HasEnvironmentUses()) {
-          for (HUseIterator<HEnvironment> use_it(current->GetEnvUses()); !use_it.Done();
+          for (HUseIterator<HEnvironment*> use_it(current->GetEnvUses()); !use_it.Done();
                use_it.Advance()) {
-            HUseListNode<HEnvironment>* user_node = use_it.Current();
+            HUseListNode<HEnvironment*>* user_node = use_it.Current();
             HEnvironment* user = user_node->GetUser();
             user->SetRawEnvAt(user_node->GetIndex(), nullptr);
-            current->RemoveEnvironmentUser(user, user_node->GetIndex());
+            current->RemoveEnvironmentUser(user_node);
           }
         }
         block->RemovePhi(current->AsPhi());
@@ -132,8 +132,8 @@ void SsaRedundantPhiElimination::Run() {
       // Because we're updating the users of this phi, we may have new
       // phis candidate for elimination if this phi is in a loop. Add phis that
       // used this phi to the worklist.
-      for (HUseIterator<HInstruction> it(phi->GetUses()); !it.Done(); it.Advance()) {
-        HUseListNode<HInstruction>* current = it.Current();
+      for (HUseIterator<HInstruction*> it(phi->GetUses()); !it.Done(); it.Advance()) {
+        HUseListNode<HInstruction*>* current = it.Current();
         HInstruction* user = current->GetUser();
         if (user->IsPhi()) {
           worklist_.Add(user->AsPhi());