[turbofan] Add the RoundInt32ToFloat32 operator to turbofan.

src/x64/assembler-x64.h

Index: src/x64/assembler-x64.h
diff --git a/src/x64/assembler-x64.h b/src/x64/assembler-x64.h
index 321185a6d7c9a56dc572f00c2ed67efd13072d5d..b2d2e9b1d52219abdcb770f88aa1fae5cb1eabc1 100644
--- a/src/x64/assembler-x64.h
+++ b/src/x64/assembler-x64.h
@@ -1025,6 +1025,7 @@ class Assembler : public AssemblerBase {
 
   void cvttss2si(Register dst, const Operand& src);
   void cvttss2si(Register dst, XMMRegister src);
+  void cvtlsi2ss(XMMRegister dst, const Operand& src);
   void cvtlsi2ss(XMMRegister dst, Register src);
 
   void andps(XMMRegister dst, XMMRegister src);
@@ -1370,6 +1371,13 @@ class Assembler : public AssemblerBase {
   void vcvtlsi2sd(XMMRegister dst, XMMRegister src1, const Operand& src2) {
     vsd(0x2a, dst, src1, src2, kF2, k0F, kW0);
   }
+  void vcvtlsi2ss(XMMRegister dst, XMMRegister src1, Register src2) {
+    XMMRegister isrc2 = {src2.code()};
+    vsd(0x2a, dst, src1, isrc2, kF3, k0F, kW0);
+  }
+  void vcvtlsi2ss(XMMRegister dst, XMMRegister src1, const Operand& src2) {
+    vsd(0x2a, dst, src1, src2, kF3, k0F, kW0);
+  }
   void vcvtqsi2ss(XMMRegister dst, XMMRegister src1, Register src2) {
     XMMRegister isrc2 = {src2.code()};
     vsd(0x2a, dst, src1, isrc2, kF3, k0F, kW1);