[Fortran] Improvements to dependency analysis

[Roger Sayle]

Hi Paul,

On Thu, 2 Mar 2006, Paul Thomas wrote:
> >The following patch makes some improvements to the gfortran front-end's
> >dependency analysis.
> >
> If I can, I will get to this in the next 24 hours.  It is an area where
> I had been meaning to get stuck in myself.  I had made some rather
> feeble forays but your contribution looks really good.

Thanks.  I've just noticed a typo re-reading through my post that
you'll probably spot straight away.  I added a new test at the
bottom of gfc_dep_resolver, that currently reads:

	if (!lref || !rref)
	  return 1;

What I'd intended to write was

	if (lref || rref)
	  return 1;

The original is safe, the condition is always true, never reached
for most array reference dependencies, and just assumes
slightly more pessimistic assumptions in rare corner cases.


I'm currently rebootstrapping and regression testing with that
change.  There should be no functional difference; this test is
to catch potential problems that we haven't ever come across yet.

Sorry for not spotting this before posting.

Roger
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