Re: [PATCH] Preserve loops from CFG build until after RTL loop opts

[Jakub Jelinek <jakub at redhat dot com>]

On Thu, Apr 25, 2013 at 04:19:20PM +0200, Richard Biener wrote:
> 
> This is the patch that I consider final as a first step (to avoid
> changing too much at once).  I've analyzed the few failures
> and compared to the previous patch changed the tree-ssa-tailmerge.c
> part to deal with merging of loop latch and loop preheader (even
> if that's a really bad idea) to not regress gcc.dg/pr50763.c.
> Any suggestion on how to improve that part welcome.
> I've had to change a few testcases, mostly in parts that are not
> really related to what they check (also reverting to a previous
> testcase state).  One remaining failure is
> 
> FAIL: gcc.dg/pr53265.c  (test for bogus messages, line 147)
> 
> which I don't want to deal with in this patch.  I can either
> followup or prepare the discussed fix of adding a copyprop
> pass before cunrolli.  Another possibility is to XFAIL the above.

As that testcase was derived from real-world code (gcc itself, if I remember
well two places actually hitting it at that point), I'd strongly prefer
the former, rather than XFAIL, because people would be pretty much annoyed
by the false positive warning, scratching heads where they invoke undefined
behavior when they actually don't.  But sure, it can wait for a follow-up
patch.

> Bootstrapped and tested on x86_64-unknown-linux-gnu for all languages
> including Ada (including 32bit multilibs).
> 
> Ok for trunk?

Yes, thanks.

	Jakub