[Bug middle-end/61409] [4.9/5 regression] -Wmaybe-uninitialized false-positive with -O2

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61409

--- Comment #13 from Jeffrey A. Law <law at redhat dot com> ---
So we don't thread this case because of the limits we place on the number of
statements in the duplicated block.

If --param max-jump-thread-duplication-stmts=16 is added to the command line,
jump threading will kick in creating the pseudo-code I posted in c#11.  For
reference, the default value of that param is 15.

What I don't understand from c#4 is uninit can't simplify this condition:

if (_35 == 4611686018595160064 (.AND.)  (.NOT.) _31 != 5) is false

While we may not know the full condition, does realizing that the (*.NOT.) _31
!= 5 is totally pointless help?