[Bug middle-end/63311] [4.9/5 Regression] -O1 optimization introduces valgrind warning

[Joost.VandeVondele at mat dot ethz.ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63311

--- Comment #8 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> ---
(In reply to Richard Biener from comment #7)
> Confirmed that it is ifcombine.  Not sure if I'd call it wrong-code though.
> 
> Note that there are no default-defs involved thus ifcombine doesn't see
> must-uninits and disabling its transform when maybe-uninits are seen
> is IMHO bogus.
> 
> Not sure what to do about this one.  There is no way to preserve evaluation
> order (no andif / orif on gimple).

just wondering if the 'target splitting the condition back' means if has a
choice which of the two to evaluate first. Be means of heuristic, if one of the
two conditions contains a 'maybe-uninit' and the other not, it is presumably
best to evaluate the 'maybe-uninit' one at the second stage ?

>From a usability point of view, I had to touch a couple of spots in our code to
make valgrind testing possible again, so while I wouldn't call this wrong-code,
it certainly is some user-visible behavior.