[Bug middle-end/114342] suboptimal codegen of vector::vector(range)

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114342

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The first memcpy (rep movsq) is for:
```
  int arr[]{-5, 10, 15, -5, 10, 15, -5, 10, 15, -5, 10, 15, -5, 10, 15, -5, 10,
15, -5, 10, 15,-5, 10, 15 -5, 10, 15, -5, 10, 15, -5, 10, 15, -5, 10, 15, -5,
10, 15, -5, 10, 15, -5, 10,-5, 10, 15, -5, 10, 15, -5, 10, 15, -5, 10, 15, -5,
10, 15, -5, 10,-5, 10, 15, -5, 10, 15, -5, 10, 15, -5, 10, 15, -5, 10, 15, -5,
10,-5, 10, 15, -5, 10, 15, -5, 10, 15, -5, 10, 15, -5, 10, 15, -5, 10,-5, 10,
15, -5, 10, 15, -5, 10, 15, -5, 10, 15, -5, 10, 15, -5, 10,};

```


The second memcpy is copying arr into the vector.
```
  _25 = operator new (444);

  <bb 3> [local count: 1073741824]:
  dd_2(D)->D.81462._M_impl.D.80768._M_start = _25;
  _16 = _25 + 444;
  dd_2(D)->D.81462._M_impl.D.80768._M_end_of_storage = _16;
  __builtin_memcpy (_25, &arr, 444);
```