[Bug tree-optimization/68775] spec2006 test case 465.tonto fails with the gcc 6.0 fortran compiler

["rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68775

--- Comment #5 from rguenther at suse dot de <rguenther at suse dot de> ---
On Wed, 9 Dec 2015, seurer at linux dot vnet.ibm.com wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68775
> 
> --- Comment #4 from William Seurer <seurer at linux dot vnet.ibm.com> ---
> (In reply to Richard Biener from comment #1)
> > Can you try to bisect to an affected source file (just use
> > -fno-tree-vectorize on all but one) and there to whether it is basic-block
> > or loop vectorization
> > (-fno-tree-loop-vectorize / -fno-tree-slp-vectorize) and specific
> > loop/basic-block with -fdbg-cnt=vect_slp:N or -fdbg-cnt=vect_loop:N?
> > 
> > Note that it seems that tonto also fails (since forever) with AVX2 on x86_64.
> 
> It still fails with just -fno-tree-vectorize but succeeds with both
> -fno-tree-loop-vectorize and -fno-tree-slp-vectorize.

That's a very odd observation as -fno-tree-vectorize should be
equivalent to -fno-tree-loop-vectorize -fno-tree-slp-vectorize.

I understand your sentence correct in that -fno-tree-loop-vectorize
makes 465.tonto no longer miscompare.  The same is true for
-fno-tree-slp-vectorize.  But with -fno-tree-vectorize 465.tonto
still miscompares?

> I am about to go through it flipping those for individual modules.

Thanks.