[Bug middle-end/70140] Inefficient expansion of __builtin_mempcpy

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70140

--- Comment #6 from Martin Liška <marxin at gcc dot gnu.org> ---
Created attachment 41772
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41772&action=edit
Patch candidate

I'm going to prepare some test-cases for that. Does it look good?