[turbofan] Introduce explicit loop exits markers.

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/address-map.h"
 #include "src/base/bits.h"
@@ skipping 2188 matching lines @@
       case IrOpcode::kTruncateInt64ToInt32:
       case IrOpcode::kChangeFloat32ToFloat64:
       case IrOpcode::kCheckedInt32Add:
       case IrOpcode::kCheckedInt32Sub:
       case IrOpcode::kCheckedUint32ToInt32:
       case IrOpcode::kCheckedFloat64ToInt32:
       case IrOpcode::kCheckedTaggedToInt32:
       case IrOpcode::kCheckedTaggedToFloat64:
       case IrOpcode::kPlainPrimitiveToWord32:
       case IrOpcode::kPlainPrimitiveToFloat64:
+      case IrOpcode::kLoopExit:
+      case IrOpcode::kLoopExitValue:
+      case IrOpcode::kLoopExitEffect:
         FATAL("Representation inference: unsupported opcodes.");
         break;
 
       default:
         VisitInputs(node);
         // Assume the output is tagged.
         return SetOutput(node, MachineRepresentation::kTagged);
     }
     UNREACHABLE();
   }
@@ skipping 1050 matching lines @@
         isolate(), graph()->zone(), callable.descriptor(), 0, flags,
         Operator::kNoProperties);
     to_number_operator_.set(common()->Call(desc));
   }
   return to_number_operator_.get();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8