[Bug rtl-optimization/127852] [16 Regression] simplify-rtx/combine can merge equal volatile accesses

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127852

--- Comment #7 from Sam James <sjames at gcc dot gnu.org> ---
I think we probably want to backport this after some soak time?