[turbofan] Introduce TruncateTaggedToWord32 simplified operator.

src/compiler/machine-operator.h

 // Copyright 2013 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.
 
 #ifndef V8_COMPILER_MACHINE_OPERATOR_H_
 #define V8_COMPILER_MACHINE_OPERATOR_H_
 
 #include "src/base/flags.h"
 #include "src/machine-type.h"
 
@@ skipping 14 matching lines @@
   bool IsSupported() const { return op_ != nullptr; }
   const Operator* op() const {
     DCHECK_NOT_NULL(op_);
     return op_;
   }
 
  private:
   const Operator* const op_;
 };
 
-
-// Supported float64 to int32 truncation modes.
-enum class TruncationMode : uint8_t {
-  kJavaScript,  // ES6 section 7.1.5
-  kRoundToZero  // Round towards zero. Implementation defined for NaN and ovf.
-};
-
-V8_INLINE size_t hash_value(TruncationMode mode) {
-  return static_cast<uint8_t>(mode);
-}
-
-std::ostream& operator<<(std::ostream&, TruncationMode);
-
-TruncationMode TruncationModeOf(Operator const*);
-
-
 // Supported write barrier modes.
 enum WriteBarrierKind {
   kNoWriteBarrier,
   kMapWriteBarrier,
   kPointerWriteBarrier,
   kFullWriteBarrier
 };
 
 std::ostream& operator<<(std::ostream& os, WriteBarrierKind);
 
@@ skipping 155 matching lines @@
   const Operator* Int64LessThan();
   const Operator* Int64LessThanOrEqual();
   const Operator* Uint64Div();
   const Operator* Uint64LessThan();
   const Operator* Uint64LessThanOrEqual();
   const Operator* Uint64Mod();
 
   // This operator reinterprets the bits of a word as tagged pointer.
   const Operator* BitcastWordToTagged();
 
+  // JavaScript float64 to int32/uint32 truncation.
+  const Operator* TruncateFloat64ToWord32();
+
   // These operators change the representation of numbers while preserving the
   // value of the number. Narrowing operators assume the input is representable
   // in the target type and are *not* defined for other inputs.
   // Use narrowing change operators only when there is a static guarantee that
   // the input value is representable in the target value.
   const Operator* ChangeFloat32ToFloat64();
   const Operator* ChangeFloat64ToInt32();   // narrowing
   const Operator* ChangeFloat64ToUint32();  // narrowing
   const Operator* TruncateFloat64ToUint32();
   const Operator* TruncateFloat32ToInt32();
   const Operator* TruncateFloat32ToUint32();
   const Operator* TryTruncateFloat32ToInt64();
   const Operator* TryTruncateFloat64ToInt64();
   const Operator* TryTruncateFloat32ToUint64();
   const Operator* TryTruncateFloat64ToUint64();
   const Operator* ChangeInt32ToFloat64();
   const Operator* ChangeInt32ToInt64();
   const Operator* ChangeUint32ToFloat64();
   const Operator* ChangeUint32ToUint64();
 
   // These operators truncate or round numbers, both changing the representation
   // of the number and mapping multiple input values onto the same output value.
   const Operator* TruncateFloat64ToFloat32();
-  const Operator* TruncateFloat64ToInt32(TruncationMode);
   const Operator* TruncateInt64ToInt32();
+  const Operator* RoundFloat64ToInt32();
   const Operator* RoundInt32ToFloat32();
   const Operator* RoundInt64ToFloat32();
   const Operator* RoundInt64ToFloat64();
   const Operator* RoundUint32ToFloat32();
   const Operator* RoundUint64ToFloat32();
   const Operator* RoundUint64ToFloat64();
 
   // These operators reinterpret the bits of a floating point number as an
   // integer and vice versa.
   const Operator* BitcastFloat32ToInt32();
@@ skipping 124 matching lines @@
 };
 
 
 DEFINE_OPERATORS_FOR_FLAGS(MachineOperatorBuilder::Flags)
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_MACHINE_OPERATOR_H_