Remove type conversion nodes converting to the same type.

When optimizing, we ensure these conversions do not reach the
code generators. When not optimizing, we cannot get such situations.

Change-Id: I717247c957667675dc261183019c88efa3a38452

1 files changed, 9 insertions, 0 deletions

diff --git a/compiler/optimizing/instruction_simplifier.cc b/compiler/optimizing/instruction_simplifier.cc
index 3d65e9a..49ca443 100644
--- a/compiler/optimizing/instruction_simplifier.cc
+++ b/compiler/optimizing/instruction_simplifier.cc
@@ -26,6 +26,7 @@ class InstructionSimplifierVisitor : public HGraphVisitor {
   void VisitSuspendCheck(HSuspendCheck* check) OVERRIDE;
   void VisitEqual(HEqual* equal) OVERRIDE;
   void VisitArraySet(HArraySet* equal) OVERRIDE;
+  void VisitTypeConversion(HTypeConversion* instruction) OVERRIDE;
 };
 
 void InstructionSimplifier::Run() {
@@ -78,4 +79,12 @@ void InstructionSimplifierVisitor::VisitArraySet(HArraySet* instruction) {
   }
 }
 
+void InstructionSimplifierVisitor::VisitTypeConversion(HTypeConversion* instruction) {
+  if (instruction->GetResultType() == instruction->GetInputType()) {
+    // Remove the instruction if it's converting to the same type.
+    instruction->ReplaceWith(instruction->GetInput());
+    instruction->GetBlock()->RemoveInstruction(instruction);
+  }
+}
+
 }  // namespace art