[Bug c/120837] [12/13/14/15/16 regression] False-positive from -fsanitize=undefined

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120837

--- Comment #17 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 61792
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=61792&action=edit
gcc16-pr120837.patch

Untested patch which instead of dropping the optimization simply performs
everything in sizetype type before final POINTER_PLUS.  It isn't recursive
admittedly.