[turbofan] Implement rounding of floats on x64 and ia32 without sse4.1.

src/ia32/macro-assembler-ia32.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_IA32_MACRO_ASSEMBLER_IA32_H_
 #define V8_IA32_MACRO_ASSEMBLER_IA32_H_
 
 #include "src/assembler.h"
 #include "src/bailout-reason.h"
 #include "src/frames.h"
@@ skipping 326 matching lines @@
 
   // Store the function for the given builtin in the target register.
   void GetBuiltinFunction(Register target, int native_context_index);
 
   // Expression support
   // cvtsi2sd instruction only writes to the low 64-bit of dst register, which
   // hinders register renaming and makes dependence chains longer. So we use
   // xorps to clear the dst register before cvtsi2sd to solve this issue.
   void Cvtsi2sd(XMMRegister dst, Register src) { Cvtsi2sd(dst, Operand(src)); }
   void Cvtsi2sd(XMMRegister dst, const Operand& src);
+  void Cvtsi2ss(XMMRegister dst, Register src) { Cvtsi2ss(dst, Operand(src)); }
+  void Cvtsi2ss(XMMRegister dst, const Operand& src);
+
+  void Roundss(XMMRegister dst, XMMRegister src, Register tmp, XMMRegister xtmp,
+               RoundingMode mode);
+  void Roundsd(XMMRegister dst, XMMRegister src, Register tmp, XMMRegister xtmp,
+               RoundingMode mode);
 
   // Support for constant splitting.
   bool IsUnsafeImmediate(const Immediate& x);
   void SafeMove(Register dst, const Immediate& x);
   void SafePush(const Immediate& x);
 
   // Compare object type for heap object.
   // Incoming register is heap_object and outgoing register is map.
   void CmpObjectType(Register heap_object, InstanceType type, Register map);
 
@@ skipping 654 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_IA32_MACRO_ASSEMBLER_IA32_H_