Fix a bug in type propagation.

If a phi requests its inputs to be of a certain type, the inputs need
to propagate that type to their users, as those users might be
phis.

Bug report and test courtesy of Serguei I Katkov.

Change-Id: I79baac271566ec4fa684c1edf11a1b3383d896a9

2 files changed, 7 insertions, 3 deletions

diff --git a/compiler/optimizing/primitive_type_propagation.cc b/compiler/optimizing/primitive_type_propagation.cc
index c20c8a172d..af93438c9a 100644
--- a/compiler/optimizing/primitive_type_propagation.cc
+++ b/compiler/optimizing/primitive_type_propagation.cc
@@ -65,6 +65,10 @@ bool PrimitiveTypePropagation::UpdateType(HPhi* phi) {
         if (equivalent->IsPhi()) {
           equivalent->AsPhi()->SetLive();
           AddToWorklist(equivalent->AsPhi());
+        } else if (equivalent == input) {
+          // The input has changed its type. It can be an input of other phis,
+          // so we need to put phi users in the work list.
+          AddDependentInstructionsToWorklist(equivalent);
         }
       }
     }
@@ -117,10 +121,10 @@ void PrimitiveTypePropagation::AddToWorklist(HPhi* instruction) {
   worklist_.Add(instruction);
 }
 
-void PrimitiveTypePropagation::AddDependentInstructionsToWorklist(HPhi* instruction) {
+void PrimitiveTypePropagation::AddDependentInstructionsToWorklist(HInstruction* instruction) {
   for (HUseIterator<HInstruction*> it(instruction->GetUses()); !it.Done(); it.Advance()) {
     HPhi* phi = it.Current()->GetUser()->AsPhi();
-    if (phi != nullptr && phi->IsLive()) {
+    if (phi != nullptr && phi->IsLive() && phi->GetType() != instruction->GetType()) {
       AddToWorklist(phi);
     }
   }
diff --git a/compiler/optimizing/primitive_type_propagation.h b/compiler/optimizing/primitive_type_propagation.h
index 1374cbb6ab..6d370ed2ab 100644
--- a/compiler/optimizing/primitive_type_propagation.h
+++ b/compiler/optimizing/primitive_type_propagation.h
@@ -33,7 +33,7 @@ class PrimitiveTypePropagation : public ValueObject {
   void VisitBasicBlock(HBasicBlock* block);
   void ProcessWorklist();
   void AddToWorklist(HPhi* phi);
-  void AddDependentInstructionsToWorklist(HPhi* phi);
+  void AddDependentInstructionsToWorklist(HInstruction* instruction);
   bool UpdateType(HPhi* phi);
 
   HGraph* const graph_;