[turbofan] Ensure that NTLs are always properly connected to the end.

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 "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties-inl.h"
 #include "src/compiler/pipeline.h"
@@ skipping 490 matching lines @@
       return VisitGoto(block->SuccessorAt(0));
     case BasicBlock::kBranch: {
       DCHECK_EQ(IrOpcode::kBranch, input->opcode());
       BasicBlock* tbranch = block->SuccessorAt(0);
       BasicBlock* fbranch = block->SuccessorAt(1);
       // SSA deconstruction requires targets of branches not to have phis.
       // Edge split form guarantees this property, but is more strict.
       CheckNoPhis(tbranch);
       CheckNoPhis(fbranch);
       if (tbranch == fbranch) return VisitGoto(tbranch);
+      // Treat special Branch(Always, IfTrue, IfFalse) as Goto(IfTrue).
+      Node* const condition = input->InputAt(0);
+      if (condition->opcode() == IrOpcode::kAlways) return VisitGoto(tbranch);
       return VisitBranch(input, tbranch, fbranch);
     }
     case BasicBlock::kReturn: {
       // If the result itself is a return, return its input.
       Node* value = (input != NULL && input->opcode() == IrOpcode::kReturn)
                         ? input->InputAt(0)
                         : input;
       return VisitReturn(value);
     }
     case BasicBlock::kThrow:
@@ skipping 13 matching lines @@
 MachineType InstructionSelector::GetMachineType(Node* node) {
   DCHECK_NOT_NULL(schedule()->block(node));  // should only use scheduled nodes.
   switch (node->opcode()) {
     case IrOpcode::kStart:
     case IrOpcode::kLoop:
     case IrOpcode::kEnd:
     case IrOpcode::kBranch:
     case IrOpcode::kIfTrue:
     case IrOpcode::kIfFalse:
     case IrOpcode::kEffectPhi:
+    case IrOpcode::kEffectSet:
     case IrOpcode::kMerge:
-    case IrOpcode::kTerminate:
       // No code needed for these graph artifacts.
       return kMachNone;
     case IrOpcode::kFinish:
       return kMachAnyTagged;
     case IrOpcode::kParameter:
       return linkage()->GetParameterType(OpParameter<int>(node));
     case IrOpcode::kOsrValue:
       return kMachAnyTagged;
     case IrOpcode::kPhi:
       return OpParameter<MachineType>(node);
@@ skipping 614 matching lines @@
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {
   return MachineOperatorBuilder::Flag::kNoFlags;
 }
 
 #endif  // !V8_TURBOFAN_BACKEND
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8