[Bug target/27855] [6/7/8 regression] reassociation causes the RA to be confused

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27855

--- Comment #57 from rguenther at suse dot de <rguenther at suse dot de> ---
On Mon, 5 Feb 2018, aldyh at gcc dot gnu.org wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27855
> 
> --- Comment #56 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
> (In reply to Richard Biener from comment #55)
> 
> > Note the original report used -O and Aldhy used -O2 but we are talking
> > about a benchmark and when you use -ffast-math you also use -O3.
> 
> Thanks, I will keep a note of this for next time.  FWIW, I used the same flags
> as the last time this was reconfirmed, which was comment #52.  I also saw a
> bunch of runs at -O2 by Uros, which likely influenced me.
> 
> > The benchmark is somewhat badly written (manually "optimized") so our
> > vectorization attempts fail.
> > 
> > Overall conclusion is I'm unsure if it's worth pursuing this bug further?
> > There is a register pressure issue left but the testcase maybe not
> > real-world enough?  That is, I would usually recommend to first un-obfuscate
> > the manually optimized code.
> 
> IMO, "manually optimized" doesn't seem to merit spending more time on this.  As
> you mention, not real world enough :).  May I suggest WONTFIX, but willing to
> reopen if someone cares enough to un-obfuscate the code?

I'd say FIXED - that sounds nicer ;)