[Bug middle-end/122871] [13/14/15/16 Regression] de-optimized synthesis of long long shift and add

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122871

--- Comment #8 from avieira at gcc dot gnu.org ---
I decided to test my hack and it passes bootstrap + regtests on
arm-none-linux-gnueabihf, aarch64-none-linux-gnu and x86_64-linux-gnu.

Maybe worth a RFC for next stage 1.