[Interpreter] Remove all Ldr style bytecodes and replace with Star lookahead.

src/interpreter/bytecode-peephole-optimizer.cc

 // Copyright 2016 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/interpreter/bytecode-peephole-optimizer.h"
 
 #include "src/objects-inl.h"
 #include "src/objects.h"
 
 namespace v8 {
@@ skipping 98 matching lines @@
   // default, the upstream bytecode generator filters out unneeded
   // expression position information so there is neglible benefit to
   // handling MAYBE specially. Hence MAYBE is treated the same as NO.
   //
   return (!last_.source_info().is_valid() ||
           !current->source_info().is_valid());
 }
 
 namespace {
 
-void TransformLdaStarToLdrLdar(Bytecode new_bytecode, BytecodeNode* const last,
-                               BytecodeNode* const current) {
-  DCHECK_EQ(current->bytecode(), Bytecode::kStar);
-
-  //
-  // An example transformation here would be:
-  //
-  //   LdaGlobal i0, i1  ____\  LdrGlobal i0, i1, R
-  //   Star R            ====/  Ldar R
-  //
-  // which loads a global value into both a register and the
-  // accumulator. However, in the second form the Ldar can often be
-  // peephole optimized away unlike the Star in the first form.
-  //
-  last->Transform(new_bytecode, current->operand(0));
-  current->set_bytecode(Bytecode::kLdar, current->operand(0));
-}
-
 void TransformLdaSmiBinaryOpToBinaryOpWithSmi(Bytecode new_bytecode,
                                               BytecodeNode* const last,
                                               BytecodeNode* const current) {
   DCHECK_EQ(last->bytecode(), Bytecode::kLdaSmi);
   current->set_bytecode(new_bytecode, last->operand(0), current->operand(0),
                         current->operand(1));
   if (last->source_info().is_valid()) {
     current->set_source_info(last->source_info());
   }
 }
@@ skipping 85 matching lines @@
 
 void BytecodePeepholeOptimizer::ChangeBytecodeAction(
     BytecodeNode* const node, const PeepholeActionAndData* action_data) {
   DCHECK(LastIsValid());
   DCHECK(!Bytecodes::IsJump(node->bytecode()));
 
   node->replace_bytecode(action_data->bytecode);
   DefaultAction(node);
 }
 
-void BytecodePeepholeOptimizer::TransformLdaStarToLdrLdarAction(
-    BytecodeNode* const node, const PeepholeActionAndData* action_data) {
-  DCHECK(LastIsValid());
-  DCHECK(!Bytecodes::IsJump(node->bytecode()));
-
-  if (!node->source_info().is_statement()) {
-    TransformLdaStarToLdrLdar(action_data->bytecode, last(), node);
-  }
-  DefaultAction(node);
-}
-
 void BytecodePeepholeOptimizer::TransformLdaSmiBinaryOpToBinaryOpWithSmiAction(
     BytecodeNode* const node, const PeepholeActionAndData* action_data) {
   DCHECK(LastIsValid());
   DCHECK(!Bytecodes::IsJump(node->bytecode()));
 
   if (!node->source_info().is_valid() || !last()->source_info().is_valid()) {
     // Fused last and current into current.
     TransformLdaSmiBinaryOpToBinaryOpWithSmi(action_data->bytecode, last(),
                                              node);
     SetLast(node);
@@ skipping 72 matching lines @@
 #undef CASE
     default:
       UNREACHABLE();
       break;
   }
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8