[Bug target/60648] [4.9 Regression] ICE (segmentation fault) in expand_binop

[law at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60648

--- Comment #3 from Jeffrey A. Law <law at redhat dot com> ---
We're getting non-canonical as part of the index computation in do_tablejump:


(gdb) p debug_rtx (index)
(plus:SI (mult:SI (const_int 0 [0])
        (const_int 4 [0x4]))
    (label_ref:SI 0))


Obviously memory_address and its children aren't prepared to deal with the
non-canonical RTL.

Not sure what this has to do with threading, other than perhaps threading
exposing "0" as the index