[turbofan] Remove unused PlainPrimitiveToNumber operator.

src/compiler/simplified-lowering.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/simplified-lowering.h"
 
 #include <limits>
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 999 matching lines @@
           node->ReplaceInput(0,
                              jsgraph_->graph()->NewNode(
                                  lowering->machine()->Float64ExtractLowWord32(),
                                  node->InputAt(0)));
           node->AppendInput(jsgraph_->zone(),
                             jsgraph_->Int32Constant(kHoleNanLower32));
           NodeProperties::ChangeOp(node, jsgraph_->machine()->Word32Equal());
         }
         break;
       }
-      case IrOpcode::kPlainPrimitiveToNumber: {
-        VisitUnop(node, UseInfo::AnyTagged(), MachineRepresentation::kTagged);
-        if (lower()) {
-          // PlainPrimitiveToNumber(x) => Call(ToNumberStub, x, no-context)
-          Operator::Properties properties = node->op()->properties();
-          Callable callable = CodeFactory::ToNumber(jsgraph_->isolate());
-          CallDescriptor::Flags flags = CallDescriptor::kNoFlags;
-          CallDescriptor* desc = Linkage::GetStubCallDescriptor(
-              jsgraph_->isolate(), jsgraph_->zone(), callable.descriptor(), 0,
-              flags, properties);
-          node->InsertInput(jsgraph_->zone(), 0,
-                            jsgraph_->HeapConstant(callable.code()));
-          node->AppendInput(jsgraph_->zone(), jsgraph_->NoContextConstant());
-          NodeProperties::ChangeOp(node, jsgraph_->common()->Call(desc));
-        }
-        break;
-      }
       case IrOpcode::kReferenceEqual: {
         VisitBinop(node, UseInfo::AnyTagged(), MachineRepresentation::kBit);
         if (lower()) {
           NodeProperties::ChangeOp(node, lowering->machine()->WordEqual());
         }
         break;
       }
       case IrOpcode::kStringEqual: {
         VisitBinop(node, UseInfo::AnyTagged(), MachineRepresentation::kTagged);
         if (lower()) {
@@ skipping 1143 matching lines @@
   if (!rhs_type->Is(type_cache_.kZeroToThirtyOne)) {
     node->ReplaceInput(1, graph()->NewNode(machine()->Word32And(), rhs,
                                            jsgraph()->Int32Constant(0x1f)));
   }
   NodeProperties::ChangeOp(node, op);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8