Remove unnecessary null checks in CheckCast and InstanceOf

Change-Id: I6fd81cabd8673be360f369e6318df0de8b18b634

1 files changed, 11 insertions, 0 deletions

diff --git a/compiler/optimizing/instruction_simplifier.cc b/compiler/optimizing/instruction_simplifier.cc
index afbc490..40ff098 100644
--- a/compiler/optimizing/instruction_simplifier.cc
+++ b/compiler/optimizing/instruction_simplifier.cc
@@ -60,6 +60,7 @@ class InstructionSimplifierVisitor : public HGraphVisitor {
   void VisitSub(HSub* instruction) OVERRIDE;
   void VisitUShr(HUShr* instruction) OVERRIDE;
   void VisitXor(HXor* instruction) OVERRIDE;
+  void VisitInstanceOf(HInstanceOf* instruction) OVERRIDE;
 
   OptimizingCompilerStats* stats_;
   bool simplification_occurred_ = false;
@@ -161,6 +162,10 @@ void InstructionSimplifierVisitor::VisitNullCheck(HNullCheck* null_check) {
 
 void InstructionSimplifierVisitor::VisitCheckCast(HCheckCast* check_cast) {
   HLoadClass* load_class = check_cast->InputAt(1)->AsLoadClass();
+  if (!check_cast->InputAt(0)->CanBeNull()) {
+    check_cast->ClearMustDoNullCheck();
+  }
+
   if (!load_class->IsResolved()) {
     // If the class couldn't be resolve it's not safe to compare against it. It's
     // default type would be Top which might be wider that the actual class type
@@ -178,6 +183,12 @@ void InstructionSimplifierVisitor::VisitCheckCast(HCheckCast* check_cast) {
   }
 }
 
+void InstructionSimplifierVisitor::VisitInstanceOf(HInstanceOf* instruction) {
+  if (!instruction->InputAt(0)->CanBeNull()) {
+    instruction->ClearMustDoNullCheck();
+  }
+}
+
 void InstructionSimplifierVisitor::VisitSuspendCheck(HSuspendCheck* check) {
   HBasicBlock* block = check->GetBlock();
   // Currently always keep the suspend check at entry.