commit 1749e2cfb5c5ed4d6970a09aecf898ca9cdfcb75
author David Brazdil <dbrazdil@google.com> Mon Sep 28 13:49:59 2015 +0100
committer David Brazdil <dbrazdil@google.com> Wed Nov 04 18:13:45 2015 +0000
tree 57ab54c48a7404abf0c9f2c919e8a6c805d98587
parent c8894ab5021aecd0fa5eba94af47f732914af33b

ART: Implement DeadPhiHandling in PrimitiveTypePropagation

DeadPhiHandling revives non-conflicting phis with environment uses
but does not properly merge types. To not duplicate code, this patch
modifies PrimitiveTypePropagation to deal with conflicts and thus
replaces DeadPhiHandling altogether.

Bug: 24252151
Bug: 24252100

Change-Id: I198c71d1b8167fc05783a5a24aa9f1e3804acafe

compiler/optimizing/nodes.h

diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index 0f2c1cf..1995797 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -4238,7 +4238,7 @@
         inputs_(number_of_inputs, arena->Adapter(kArenaAllocPhiInputs)),
         reg_number_(reg_number),
         type_(type),
-        is_live_(false),
+        is_live_(true),
         can_be_null_(true) {
   }
 
@@ -4263,7 +4263,18 @@
   void RemoveInputAt(size_t index);
 
   Primitive::Type GetType() const OVERRIDE { return type_; }
-  void SetType(Primitive::Type type) { type_ = type; }
+  void SetType(Primitive::Type new_type) {
+    // Make sure that only valid type changes occur. The following are allowed:
+    //  (1) void -> * (initial type assignment),
+    //  (2) int  -> float/ref (primitive type propagation),
+    //  (3) long -> double (primitive type propagation).
+    DCHECK(type_ == new_type ||
+           type_ == Primitive::kPrimVoid ||
+           (type_ == Primitive::kPrimInt && new_type == Primitive::kPrimFloat) ||
+           (type_ == Primitive::kPrimInt && new_type == Primitive::kPrimNot) ||
+           (type_ == Primitive::kPrimLong && new_type == Primitive::kPrimDouble));
+    type_ = new_type;
+  }
 
   bool CanBeNull() const OVERRIDE { return can_be_null_; }
   void SetCanBeNull(bool can_be_null) { can_be_null_ = can_be_null; }
@@ -4485,7 +4496,8 @@
             SideEffects additional_side_effects = SideEffects::None())
       : HExpression(type,
                     SideEffects::ArrayReadOfType(type).Union(additional_side_effects),
-                    dex_pc) {
+                    dex_pc),
+        fixed_type_(type != Primitive::kPrimInt && type != Primitive::kPrimLong) {
     SetRawInputAt(0, array);
     SetRawInputAt(1, index);
   }
@@ -4503,7 +4515,13 @@
     return false;
   }
 
-  void SetType(Primitive::Type type) { type_ = type; }
+  void SetType(Primitive::Type type) {
+    DCHECK(type_ == type || !IsTypeFixed());
+    type_ = type;
+  }
+
+  bool IsTypeFixed() const { return fixed_type_; }
+  void FixType() { fixed_type_ = true; }
 
   HInstruction* GetArray() const { return InputAt(0); }
   HInstruction* GetIndex() const { return InputAt(1); }
@@ -4511,6 +4529,12 @@
   DECLARE_INSTRUCTION(ArrayGet);
 
  private:
+  // Bytecode aget(-wide) instructions have ambiguous type (int/float, long/double).
+  // If the type can be determined from uses, `fixed_type_` should be set to true,
+  // to prevent PrimitiveTypePropagation from changing it while typing phis. With
+  // other aget-* variants, the type is always unambiguous.
+  bool fixed_type_;
+
   DISALLOW_COPY_AND_ASSIGN(HArrayGet);
 };