[Bug target/93737] inline memmove for insertion into small arrays

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93737

--- Comment #3 from Martin Sebor <msebor at gcc dot gnu.org> ---
I was thinking for small N, the middle-end could make it work by emitting
copies of the sequences using MEM_REFs, along these lines:

  char _2[N - 2];
  _2 = MEM <char[N - 2]> [(char * {ref-all})&a + 1];
  MEM <char[N - 2]> [(char * {ref-all})&a + 2] = _2;