[Bug c++/91993] [8/9/10 Regression] Spurious -Wconversion warning with -fsanitize=undefined since r6-4886-gcda0a029f45d20f4

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91993

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 47971
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47971&action=edit
gcc10-pr91993-wip.patch

As implemented in this completely untested (so far) patch, which makes the
-Wconversion warning go away both in the case of comma operator with user
side-effects as well as -fsanitize=undefined.