[Bug tree-optimization/127968] [16/17 Regression] wrong code at -O1, -O2 and -Os with partially overlapping memcpy in a loop since r16-5526

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127968

--- Comment #3 from kugan at gcc dot gnu.org ---
Created attachment 65915
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=65915&action=edit
Patch