[Bug rtl-optimization/66087] Invalid narrowing of MEM with containing POST_INC

[mikpelinux at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66087

--- Comment #4 from Mikael Pettersson <mikpelinux at gmail dot com> ---
Still miscompiled by gcc-10.0, 9.1, and 8.3 at -O1 and above.