[turbofan] fine grained move operand merge optimization

test/unittests/compiler/move-optimizer-unittest.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/move-optimizer.h"
 #include "test/unittests/compiler/instruction-sequence-unittest.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
@@ skipping 228 matching lines @@
       ++assignment;
       CHECK(move->destination().IsRegister());
       CHECK(move->source().IsConstant());
     }
   }
   CHECK_EQ(1, redundants);
   CHECK_EQ(1, assignment);
 }
 
 
+TEST_F(MoveOptimizerTest, SubsetMovesMerge) {
+  StartBlock();
+  EndBlock(Branch(Imm(), 1, 2));
+
+  StartBlock();
+  EndBlock(Jump(2));
+  Instruction* last_move_b1 = LastInstruction();
+  AddMove(last_move_b1, Reg(0), Reg(1));
+  AddMove(last_move_b1, Reg(2), Reg(3));
+
+  StartBlock();
+  EndBlock(Jump(1));
+  Instruction* last_move_b2 = LastInstruction();
+  AddMove(last_move_b2, Reg(0), Reg(1));
+  AddMove(last_move_b2, Reg(4), Reg(5));
+
+  StartBlock();
+  EndBlock(Last());
+
+  Instruction* last = LastInstruction();
+
+  Optimize();
+
+  ParallelMove* last_move = last->parallel_moves()[0];
+  CHECK_EQ(1, NonRedundantSize(last_move));
+  CHECK(Contains(last_move, Reg(0), Reg(1)));
+
+  ParallelMove* b1_move = last_move_b1->parallel_moves()[0];
+  CHECK_EQ(1, NonRedundantSize(b1_move));
+  CHECK(Contains(b1_move, Reg(2), Reg(3)));
+
+  ParallelMove* b2_move = last_move_b2->parallel_moves()[0];
+  CHECK_EQ(1, NonRedundantSize(b2_move));
+  CHECK(Contains(b2_move, Reg(4), Reg(5)));
+}
+
+
+TEST_F(MoveOptimizerTest, GapConflictSubsetMovesDoNotMerge) {
+  StartBlock();
+  EndBlock(Branch(Imm(), 1, 2));
+
+  StartBlock();
+  EndBlock(Jump(2));
+  Instruction* last_move_b1 = LastInstruction();
+  AddMove(last_move_b1, Reg(0), Reg(1));
+  AddMove(last_move_b1, Reg(2), Reg(0));
+  AddMove(last_move_b1, Reg(4), Reg(5));
+
+  StartBlock();
+  EndBlock(Jump(1));
+  Instruction* last_move_b2 = LastInstruction();
+  AddMove(last_move_b2, Reg(0), Reg(1));
+  AddMove(last_move_b2, Reg(4), Reg(5));
+
+  StartBlock();
+  EndBlock(Last());
+
+  Instruction* last = LastInstruction();
+
+  Optimize();
+
+  ParallelMove* last_move = last->parallel_moves()[0];
+  CHECK_EQ(1, NonRedundantSize(last_move));
+  CHECK(Contains(last_move, Reg(4), Reg(5)));
+
+  ParallelMove* b1_move = last_move_b1->parallel_moves()[0];
+  CHECK_EQ(2, NonRedundantSize(b1_move));
+  CHECK(Contains(b1_move, Reg(0), Reg(1)));
+  CHECK(Contains(b1_move, Reg(2), Reg(0)));
+
+  ParallelMove* b2_move = last_move_b2->parallel_moves()[0];
+  CHECK_EQ(1, NonRedundantSize(b2_move));
+  CHECK(Contains(b1_move, Reg(0), Reg(1)));
+}
+
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8