[Bug middle-end/83653] [6/7/8 Regression] GCC fails to remove a can't-happen call on ia64

[matthew at wil dot cx]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83653

--- Comment #14 from Matthew Wilcox <matthew at wil dot cx> ---
Confirmed this fixes the problem.  I'll send it to Tony and see if he likes it.
 May I add your Signed-off-by to the patch?