commit 2bd4c5c1b704be8a81d9b7a94b3e828afa2b0963
author David Brazdil <dbrazdil@google.com> Wed Nov 04 22:48:45 2015 +0000
committer David Brazdil <dbrazdil@google.com> Wed Nov 04 22:48:45 2015 +0000
tree ee1ea3271d41b9a647a7ce7e4d1a0ed94eff9fcf
parent 1749e2cfb5c5ed4d6970a09aecf898ca9cdfcb75

Revert "ART: Implement DeadPhiHandling in PrimitiveTypePropagation"

Crashes on YouTube, need to investigate

This reverts commit 1749e2cfb5c5ed4d6970a09aecf898ca9cdfcb75.

Change-Id: If5f133d55dcc26b8db79a670a48fbd4af7807556

compiler/optimizing/ssa_phi_elimination.cc

diff --git a/compiler/optimizing/ssa_phi_elimination.cc b/compiler/optimizing/ssa_phi_elimination.cc
index c6993f3..72f9ddd 100644
--- a/compiler/optimizing/ssa_phi_elimination.cc
+++ b/compiler/optimizing/ssa_phi_elimination.cc
@@ -29,28 +29,17 @@
     HBasicBlock* block = it.Current();
     for (HInstructionIterator inst_it(block->GetPhis()); !inst_it.Done(); inst_it.Advance()) {
       HPhi* phi = inst_it.Current()->AsPhi();
-      if (phi->IsDead()) {
-        // Phis are constructed live so this one was proven conflicting.
-        continue;
-      }
-
-      bool is_live = false;
-      if (graph_->IsDebuggable() && phi->HasEnvironmentUses()) {
-        is_live = true;
-      } else {
-        for (HUseIterator<HInstruction*> use_it(phi->GetUses()); !use_it.Done(); use_it.Advance()) {
-          if (!use_it.Current()->GetUser()->IsPhi()) {
-            is_live = true;
-            break;
-          }
+      // 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();
+        HInstruction* user = current->GetUser();
+        if (!user->IsPhi()) {
+          worklist_.push_back(phi);
+          phi->SetLive();
+          break;
         }
       }
-
-      if (is_live) {
-        worklist_.push_back(phi);
-      } else {
-        phi->SetDead();
-      }
     }
   }
 
@@ -61,10 +50,8 @@
     for (HInputIterator it(phi); !it.Done(); it.Advance()) {
       HInstruction* input = it.Current();
       if (input->IsPhi() && input->AsPhi()->IsDead()) {
-        // If we revive a phi it must have been live at the beginning of
-        // the pass but had no non-phi uses of its own.
-        input->AsPhi()->SetLive();
         worklist_.push_back(input->AsPhi());
+        input->AsPhi()->SetLive();
       }
     }
   }
@@ -88,8 +75,8 @@
           for (HUseIterator<HInstruction*> use_it(phi->GetUses()); !use_it.Done();
                use_it.Advance()) {
             HInstruction* user = use_it.Current()->GetUser();
-            DCHECK(user->IsPhi());
-            DCHECK(user->AsPhi()->IsDead());
+            DCHECK(user->IsLoopHeaderPhi()) << user->GetId();
+            DCHECK(user->AsPhi()->IsDead()) << user->GetId();
           }
         }
         // Remove the phi from use lists of its inputs.