[turbofan] Add proper conversion operators for int32<->int64.

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/compiler/machine-type.h"
 #include "src/compiler/opcodes.h"
 #include "src/compiler/operator.h"
@@ skipping 103 matching lines @@
   Operator* Int64Add() { BINOP_AC(Int64Add); }
   Operator* Int64Sub() { BINOP(Int64Sub); }
   Operator* Int64Mul() { BINOP_AC(Int64Mul); }
   Operator* Int64Div() { BINOP(Int64Div); }
   Operator* Int64UDiv() { BINOP(Int64UDiv); }
   Operator* Int64Mod() { BINOP(Int64Mod); }
   Operator* Int64UMod() { BINOP(Int64UMod); }
   Operator* Int64LessThan() { BINOP(Int64LessThan); }
   Operator* Int64LessThanOrEqual() { BINOP(Int64LessThanOrEqual); }
 
-  Operator* ConvertInt32ToInt64() { UNOP(ConvertInt32ToInt64); }
-  Operator* ConvertInt64ToInt32() { UNOP(ConvertInt64ToInt32); }
-
   // Convert representation of integers between float64 and int32/uint32.
   // The precise rounding mode and handling of out of range inputs are *not*
   // defined for these operators, since they are intended only for use with
   // integers.
-  // TODO(titzer): rename ConvertXXX to ChangeXXX in machine operators.
   Operator* ChangeInt32ToFloat64() { UNOP(ChangeInt32ToFloat64); }
   Operator* ChangeUint32ToFloat64() { UNOP(ChangeUint32ToFloat64); }
   Operator* ChangeFloat64ToInt32() { UNOP(ChangeFloat64ToInt32); }
   Operator* ChangeFloat64ToUint32() { UNOP(ChangeFloat64ToUint32); }
 
+  // Sign/zero extend int32/uint32 to int64/uint64.
+  Operator* ChangeInt32ToInt64() { UNOP(ChangeInt32ToInt64); }
+  Operator* ChangeUint32ToUint64() { UNOP(ChangeUint32ToUint64); }
+
+  // Truncate the high order bits and convert the remaining bits to int32.
+  Operator* TruncateInt64ToInt32() { UNOP(TruncateInt64ToInt32); }
+
   // Floating point operators always operate with IEEE 754 round-to-nearest.
   Operator* Float64Add() { BINOP_C(Float64Add); }
   Operator* Float64Sub() { BINOP(Float64Sub); }
   Operator* Float64Mul() { BINOP_C(Float64Mul); }
   Operator* Float64Div() { BINOP(Float64Div); }
   Operator* Float64Mod() { BINOP(Float64Mod); }
 
   // Floating point comparisons complying to IEEE 754.
   Operator* Float64Equal() { BINOP_C(Float64Equal); }
   Operator* Float64LessThan() { BINOP(Float64LessThan); }
@@ skipping 15 matching lines @@
 
  private:
   Zone* zone_;
   MachineType word_;
 };
 }
 }
 }  // namespace v8::internal::compiler
 
 #endif  // V8_COMPILER_MACHINE_OPERATOR_H_