[Bug middle-end/87248] [6/7/8/9 Regression] Bad code for masked operations involving signed ints

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87248

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 44671
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44671&action=edit
gcc9-pr87248.patch

Untested fix.