Implemented the RoundInt64ToFloat32 TurboFan operator for x64, arm64, and mips64.

src/compiler/opcodes.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_OPCODES_H_
 #define V8_COMPILER_OPCODES_H_
 
 #include <iosfwd>
 
 // Opcodes for control operators.
@@ skipping 255 matching lines @@
   V(ChangeFloat64ToInt32)       \
   V(ChangeFloat64ToUint32)      \
   V(ChangeInt32ToFloat64)       \
   V(ChangeInt32ToInt64)         \
   V(ChangeUint32ToFloat64)      \
   V(ChangeUint32ToUint64)       \
   V(TruncateFloat64ToFloat32)   \
   V(TruncateFloat64ToInt32)     \
   V(TruncateInt64ToInt32)       \
   V(RoundInt64ToFloat64)        \
+  V(RoundInt64ToFloat32)        \
   V(BitcastFloat32ToInt32)      \
   V(BitcastFloat64ToInt64)      \
   V(BitcastInt32ToFloat32)      \
   V(BitcastInt64ToFloat64)      \
   V(Float32Add)                 \
   V(Float32Sub)                 \
   V(Float32Mul)                 \
   V(Float32Div)                 \
   V(Float32Max)                 \
   V(Float32Min)                 \
@@ skipping 92 matching lines @@
   }
 };
 
 std::ostream& operator<<(std::ostream&, IrOpcode::Value);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_OPCODES_H_