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

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

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

--- Comment #5 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
Seems plausible.  GCC-10 generates poor code for

a * 0x200000001LL