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

src/x64/macro-assembler-x64.h

 // Copyright 2012 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_X64_MACRO_ASSEMBLER_X64_H_
 #define V8_X64_MACRO_ASSEMBLER_X64_H_
 
 #include "src/assembler.h"
 #include "src/bailout-reason.h"
 #include "src/base/flags.h"
@@ skipping 799 matching lines @@
   void Cvtss2sd(XMMRegister dst, XMMRegister src);
   void Cvtss2sd(XMMRegister dst, const Operand& src);
   void Cvtsd2ss(XMMRegister dst, XMMRegister src);
   void Cvtsd2ss(XMMRegister dst, const Operand& src);
 
   // cvtsi2sd instruction only writes to the low 64-bit of dst register, which
   // hinders register renaming and makes dependence chains longer. So we use
   // xorpd to clear the dst register before cvtsi2sd to solve this issue.
   void Cvtlsi2sd(XMMRegister dst, Register src);
   void Cvtlsi2sd(XMMRegister dst, const Operand& src);
+
+  void Cvtqsi2ss(XMMRegister dst, Register src);
+  void Cvtqsi2ss(XMMRegister dst, const Operand& src);
+
   void Cvtqsi2sd(XMMRegister dst, Register src);
   void Cvtqsi2sd(XMMRegister dst, const Operand& src);
 
   void Cvtsd2si(Register dst, XMMRegister src);
 
   void Cvttsd2si(Register dst, XMMRegister src);
   void Cvttsd2si(Register dst, const Operand& src);
   void Cvttsd2siq(Register dst, XMMRegister src);
   void Cvttsd2siq(Register dst, const Operand& src);
 
@@ skipping 893 matching lines @@
   }                                                                          \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_