Merge "Optimizing: Improve constant folding + DCE for inlining."

3 files changed, 16 insertions, 1 deletions

diff --git a/compiler/optimizing/inliner.cc b/compiler/optimizing/inliner.cc
index 353881e47a..c9319f5d07 100644
--- a/compiler/optimizing/inliner.cc
+++ b/compiler/optimizing/inliner.cc
@@ -406,8 +406,8 @@ bool HInliner::TryBuildAndInline(ArtMethod* resolved_method,
     &type_propagation,
     &sharpening,
     &simplify,
-    &dce,
     &fold,
+    &dce,
   };
 
   for (size_t i = 0; i < arraysize(optimizations); ++i) {
diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index 8100b58ae6..716888a269 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -1095,6 +1095,8 @@ HConstant* HBinaryOperation::TryStaticEvaluation() const {
     } else if (GetRight()->IsLongConstant()) {
       return Evaluate(GetLeft()->AsLongConstant(), GetRight()->AsLongConstant());
     }
+  } else if (GetLeft()->IsNullConstant() && GetRight()->IsNullConstant()) {
+    return Evaluate(GetLeft()->AsNullConstant(), GetRight()->AsNullConstant());
   }
   return nullptr;
 }
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index a3f3d17b9d..7ea6176e96 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -2595,6 +2595,11 @@ class HBinaryOperation : public HExpression<2> {
     VLOG(compiler) << DebugName() << " is not defined for the (long, int) case.";
     return nullptr;
   }
+  virtual HConstant* Evaluate(HNullConstant* x ATTRIBUTE_UNUSED,
+                              HNullConstant* y ATTRIBUTE_UNUSED) const {
+    VLOG(compiler) << DebugName() << " is not defined for the (null, null) case.";
+    return nullptr;
+  }
 
   // Returns an input that can legally be used as the right input and is
   // constant, or null.
@@ -2685,6 +2690,10 @@ class HEqual : public HCondition {
     return GetBlock()->GetGraph()->GetIntConstant(
         Compute(x->GetValue(), y->GetValue()), GetDexPc());
   }
+  HConstant* Evaluate(HNullConstant* x ATTRIBUTE_UNUSED,
+                      HNullConstant* y ATTRIBUTE_UNUSED) const OVERRIDE {
+    return GetBlock()->GetGraph()->GetConstant(GetType(), 1);
+  }
 
   DECLARE_INSTRUCTION(Equal);
 
@@ -2717,6 +2726,10 @@ class HNotEqual : public HCondition {
     return GetBlock()->GetGraph()->GetIntConstant(
         Compute(x->GetValue(), y->GetValue()), GetDexPc());
   }
+  HConstant* Evaluate(HNullConstant* x ATTRIBUTE_UNUSED,
+                      HNullConstant* y ATTRIBUTE_UNUSED) const OVERRIDE {
+    return GetBlock()->GetGraph()->GetConstant(GetType(), 0);
+  }
 
   DECLARE_INSTRUCTION(NotEqual);