Merge "ART: Dead block removal"

1 files changed, 21 insertions, 9 deletions

diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index b89487f4f6..18a8225f55 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -97,6 +97,9 @@ class HInstructionList {
   void AddAfter(HInstruction* cursor, const HInstructionList& instruction_list);
   void Add(const HInstructionList& instruction_list);
 
+  // Return the number of instructions in the list. This is an expensive operation.
+  size_t CountSize() const;
+
  private:
   HInstruction* first_instruction_;
   HInstruction* last_instruction_;
@@ -168,7 +171,8 @@ class HGraph : public ArenaObject<kArenaAllocMisc> {
   // Inline this graph in `outer_graph`, replacing the given `invoke` instruction.
   void InlineInto(HGraph* outer_graph, HInvoke* invoke);
 
-  void MergeEmptyBranches(HBasicBlock* start_block, HBasicBlock* end_block);
+  // Removes `block` from the graph.
+  void DeleteDeadBlock(HBasicBlock* block);
 
   void SplitCriticalEdge(HBasicBlock* block, HBasicBlock* successor);
   void SimplifyLoop(HBasicBlock* header);
@@ -248,8 +252,9 @@ class HGraph : public ArenaObject<kArenaAllocMisc> {
     return CreateConstant(value, &cached_long_constants_);
   }
 
- private:
   HBasicBlock* FindCommonDominator(HBasicBlock* first, HBasicBlock* second) const;
+
+ private:
   void VisitBlockForDominatorTree(HBasicBlock* block,
                                   HBasicBlock* predecessor,
                                   GrowableArray<size_t>* visits);
@@ -451,6 +456,7 @@ class HBasicBlock : public ArenaObject<kArenaAllocMisc> {
   HBasicBlock* GetDominator() const { return dominator_; }
   void SetDominator(HBasicBlock* dominator) { dominator_ = dominator; }
   void AddDominatedBlock(HBasicBlock* block) { dominated_blocks_.Add(block); }
+  void RemoveDominatedBlock(HBasicBlock* block) { dominated_blocks_.Delete(block); }
   void ReplaceDominatedBlock(HBasicBlock* existing, HBasicBlock* new_block) {
     for (size_t i = 0, e = dominated_blocks_.Size(); i < e; ++i) {
       if (dominated_blocks_.Get(i) == existing) {
@@ -550,7 +556,7 @@ class HBasicBlock : public ArenaObject<kArenaAllocMisc> {
   // that this method does not update the graph, reverse post order, loop
   // information, nor make sure the blocks are consistent (for example ending
   // with a control flow instruction).
-  void MergeWith(HBasicBlock* other);
+  void MergeWithInlined(HBasicBlock* other);
 
   // Replace `this` with `other`. Predecessors, successors, and dominated blocks
   // of `this` are moved to `other`.
@@ -559,12 +565,17 @@ class HBasicBlock : public ArenaObject<kArenaAllocMisc> {
   // with a control flow instruction).
   void ReplaceWith(HBasicBlock* other);
 
-  // Disconnects `this` from all its predecessors, successors and the dominator.
-  // It assumes that `this` does not dominate any blocks.
-  // Note that this method does not update the graph, reverse post order, loop
-  // information, nor make sure the blocks are consistent (for example ending
-  // with a control flow instruction).
-  void DisconnectFromAll();
+  // Merge `other` at the end of `this`. This method updates loops, reverse post
+  // order, links to predecessors, successors, dominators and deletes the block
+  // from the graph. The two blocks must be successive, i.e. `this` the only
+  // predecessor of `other` and vice versa.
+  void MergeWith(HBasicBlock* other);
+
+  // Disconnects `this` from all its predecessors, successors and dominator,
+  // removes it from all loops it is included in and eventually from the graph.
+  // The block must not dominate any other block. Predecessors and successors
+  // are safely updated.
+  void DisconnectAndDelete();
 
   void AddInstruction(HInstruction* instruction);
   void InsertInstructionBefore(HInstruction* instruction, HInstruction* cursor);
@@ -2746,6 +2757,7 @@ class HPhi : public HInstruction {
   size_t InputCount() const OVERRIDE { return inputs_.Size(); }
 
   void AddInput(HInstruction* input);
+  void RemoveInputAt(size_t index);
 
   Primitive::Type GetType() const OVERRIDE { return type_; }
   void SetType(Primitive::Type type) { type_ = type; }