[turbofan]: Elide extra move when accessing stack or frame register

src/compiler/register-allocator-verifier.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/bit-vector.h"
 #include "src/compiler/instruction.h"
 #include "src/compiler/register-allocator-verifier.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 30 matching lines @@
     }
   }
 }
 
 }  // namespace
 
 
 void RegisterAllocatorVerifier::VerifyInput(
     const OperandConstraint& constraint) {
   CHECK_NE(kSameAsFirst, constraint.type_);
-  if (constraint.type_ != kImmediate) {
+  if (constraint.type_ != kImmediate &&
+      constraint.type_ != kStandardFrameRegister) {
     CHECK_NE(InstructionOperand::kInvalidVirtualRegister,
              constraint.virtual_register_);
   }
 }
 
 
 void RegisterAllocatorVerifier::VerifyTemp(
     const OperandConstraint& constraint) {
   CHECK_NE(kSameAsFirst, constraint.type_);
   CHECK_NE(kImmediate, constraint.type_);
@@ skipping 80 matching lines @@
   if (op->IsConstant()) {
     constraint->type_ = kConstant;
     constraint->value_ = ConstantOperand::cast(op)->virtual_register();
     constraint->virtual_register_ = constraint->value_;
   } else if (op->IsImmediate()) {
     auto imm = ImmediateOperand::cast(op);
     int value = imm->type() == ImmediateOperand::INLINE ? imm->inline_value()
                                                         : imm->indexed_value();
     constraint->type_ = kImmediate;
     constraint->value_ = value;
+  } else if (op->IsStackPointer() || op->IsFramePointer()) {
+    constraint->type_ = kStandardFrameRegister;
   } else {
     CHECK(op->IsUnallocated());
     const auto* unallocated = UnallocatedOperand::cast(op);
     int vreg = unallocated->virtual_register();
     constraint->virtual_register_ = vreg;
     if (unallocated->basic_policy() == UnallocatedOperand::FIXED_SLOT) {
       constraint->type_ = kFixedSlot;
       constraint->value_ = unallocated->fixed_slot_index();
     } else {
       switch (unallocated->extended_policy()) {
@@ skipping 48 matching lines @@
       return;
     case kImmediate: {
       CHECK(op->IsImmediate());
       auto imm = ImmediateOperand::cast(op);
       int value = imm->type() == ImmediateOperand::INLINE
                       ? imm->inline_value()
                       : imm->indexed_value();
       CHECK_EQ(value, constraint->value_);
       return;
     }
+    case kStandardFrameRegister:
+      return;
     case kRegister:
       CHECK(op->IsRegister());
       return;
     case kFixedRegister:
       CHECK(op->IsRegister());
       CHECK_EQ(RegisterOperand::cast(op)->index(), constraint->value_);
       return;
     case kDoubleRegister:
       CHECK(op->IsDoubleRegister());
       return;
@@ skipping 443 matching lines @@
     auto current = block_maps->InitializeIncoming(block_index, initial_pass);
     const auto block = sequence()->instruction_blocks()[block_index];
     for (int instr_index = block->code_start(); instr_index < block->code_end();
          ++instr_index) {
       const auto& instr_constraint = constraints_[instr_index];
       const auto instr = instr_constraint.instruction_;
       current->RunGaps(zone(), instr);
       const auto op_constraints = instr_constraint.operand_constraints_;
       size_t count = 0;
       for (size_t i = 0; i < instr->InputCount(); ++i, ++count) {
-        if (op_constraints[count].type_ == kImmediate) continue;
+        if (op_constraints[count].type_ == kImmediate ||
+            op_constraints[count].type_ == kStandardFrameRegister)
+          continue;
         int virtual_register = op_constraints[count].virtual_register_;
         auto op = instr->InputAt(i);
         if (!block_maps->IsPhi(virtual_register)) {
           current->Use(op, virtual_register, initial_pass);
         } else {
           auto phi = block_maps->GetPhi(virtual_register);
           current->UsePhi(op, phi, initial_pass);
         }
       }
       for (size_t i = 0; i < instr->TempCount(); ++i, ++count) {
         current->Drop(instr->TempAt(i));
       }
       if (instr->IsCall()) {
         current->DropRegisters(config());
       }
       for (size_t i = 0; i < instr->OutputCount(); ++i, ++count) {
         int virtual_register = op_constraints[count].virtual_register_;
         current->Define(zone(), instr->OutputAt(i), virtual_register);
       }
     }
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8