[Bug target/124029] Improve sgt with certain constants for riscv

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124029

--- Comment #2 from Jeffrey A. Law <law at gcc dot gnu.org> ---
Whoops.  Obviously there's an adjustment to be made there.   

(gt (x) (0xfffffff)) -> (le (0x10000000) (x))