[x64] Implement vcvtqsi2sd AVX instruction.

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 371a6770f88c40d170583a63d9f7f5d42800d2d4..3d929b17fa3026df82d0b082d3fc14c93df9f484 100644
--- a/src/x64/assembler-x64.h
+++ b/src/x64/assembler-x64.h
@@ -1359,6 +1359,10 @@ class Assembler : public AssemblerBase {
   void vcvtlsi2sd(XMMRegister dst, XMMRegister src1, const Operand& src2) {
     vsd(0x2a, dst, src1, src2, kF2, k0F, kW0);
   }
+  void vcvtqsi2sd(XMMRegister dst, XMMRegister src1, Register src2) {
+    XMMRegister isrc2 = {src2.code()};
+    vsd(0x2a, dst, src1, isrc2, kF2, k0F, kW1);
+  }
   void vcvttsd2si(Register dst, XMMRegister src) {
     XMMRegister idst = {dst.code()};
     vsd(0x2c, idst, xmm0, src, kF2, k0F, kW0);