[Bug bootstrap/71071] [7 regression] ICE --enable-checking=fold : fold check: original tree changed by fold

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71071

--- Comment #8 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
And the place where we change the alias set?  Since r236117 we call
get_alias_set when building the ref in make_bit_field_ref, and that's what
changes the alias set of "a".