[Bug tree-optimization/127521] [15/16/17 Regression] `ifcombine` incorrectly removes a masked sign-bit condition

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127521

--- Comment #1 from Drea Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 65655
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=65655&action=edit
Generic testcase

Assumes `sizeof(short) == 2`.