[Bug tree-optimization/52275] The polyhedron test air.f90 is miscompiled with '-O2 -floop-flatten' after revision 184265

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52275

--- Comment #2 from Dominique d'Humieres <dominiq at lps dot ens.fr> 2012-02-16 13:46:30 UTC ---
> If I apply the pseudo-patch at the end, air still works fine at -O3 or -O2 on
> x86_64-linux.  So, what exactly is miscompiled with that patch applied?  -O2
> -fgraphite-identity?  Something else?

Please read the beginning of the post:

> Revision 184265 fixes the ICE I saw on the 2005 polyhedron test air.f90.
> However as reported in comment #9 of pr50561, the test is miscompiled with '-O2
> -floop-flatten' and higher optimization:

Can it be clearer?