[turbofan] Add the RoundInt32ToFloat32 operator to turbofan.

src/ia32/assembler-ia32.h

Index: src/ia32/assembler-ia32.h
diff --git a/src/ia32/assembler-ia32.h b/src/ia32/assembler-ia32.h
index 2b241cc7c55825260e1d735d61736c931e28e104..85ff3911a8d7f29e39137d12bb0c88de07e9749b 100644
--- a/src/ia32/assembler-ia32.h
+++ b/src/ia32/assembler-ia32.h
@@ -960,6 +960,8 @@ class Assembler : public AssemblerBase {
   }
   void cvtsd2si(Register dst, XMMRegister src);
 
+  void cvtsi2ss(XMMRegister dst, Register src) { cvtsi2ss(dst, Operand(src)); }
+  void cvtsi2ss(XMMRegister dst, const Operand& src);
   void cvtsi2sd(XMMRegister dst, Register src) { cvtsi2sd(dst, Operand(src)); }
   void cvtsi2sd(XMMRegister dst, const Operand& src);
   void cvtss2sd(XMMRegister dst, const Operand& src);