Simplified 'return' handling in the instruction selector.

src/compiler/instruction-selector.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/instruction-selector.h"
 
 #include <limits>
 
 #include "src/base/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
@@ skipping 540 matching lines @@
       }
       DCHECK_LE(sw.min_value, sw.max_value);
       // Note that {value_range} can be 0 if {min_value} is -2^31 and
       // {max_value}
       // is 2^31-1, so don't assume that it's non-zero below.
       sw.value_range = 1u + bit_cast<uint32_t>(sw.max_value) -
                        bit_cast<uint32_t>(sw.min_value);
       return VisitSwitch(input, sw);
     }
     case BasicBlock::kReturn: {
-      // If the result itself is a return, return its input.
-      Node* value = (input != nullptr && input->opcode() == IrOpcode::kReturn)
-                        ? input->InputAt(0)
-                        : input;
-      return VisitReturn(value);
+      DCHECK_EQ(IrOpcode::kReturn, input->opcode());
+      return VisitReturn(input->InputAt(0));
     }
     case BasicBlock::kDeoptimize: {
       // If the result itself is a return, return its input.
       Node* value =
           (input != nullptr && input->opcode() == IrOpcode::kDeoptimize)
               ? input->InputAt(0)
               : input;
       return VisitDeoptimize(value);
     }
     case BasicBlock::kThrow:
@@ skipping 462 matching lines @@
 
 
 void InstructionSelector::VisitGoto(BasicBlock* target) {
   // jump to the next block.
   OperandGenerator g(this);
   Emit(kArchJmp, g.NoOutput(), g.Label(target));
 }
 
 
 void InstructionSelector::VisitReturn(Node* value) {
+  DCHECK_NOT_NULL(value);
   OperandGenerator g(this);
-  if (value != NULL) {
-    Emit(kArchRet, g.NoOutput(),
-         g.UseLocation(value, linkage()->GetReturnLocation(),
-                       linkage()->GetReturnType()));
-  } else {
-    Emit(kArchRet, g.NoOutput());
-  }
+  Emit(kArchRet, g.NoOutput(),
+       g.UseLocation(value, linkage()->GetReturnLocation(),
+                     linkage()->GetReturnType()));
 }
 
 
 void InstructionSelector::VisitDeoptimize(Node* value) {
   DCHECK(FLAG_turbo_deoptimization);
 
   OperandGenerator g(this);
 
   FrameStateDescriptor* desc = GetFrameStateDescriptor(value);
   size_t arg_count = desc->GetTotalSize() + 1;  // Include deopt id.
@@ skipping 134 matching lines @@
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {
   return MachineOperatorBuilder::Flag::kNoFlags;
 }
 
 #endif  // !V8_TURBOFAN_BACKEND
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8