[Bug tree-optimization/33113] Failing to represent the stride (with array) of a dataref when it is not a constant

["rakdver at kam dot mff dot cuni dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #3 from rakdver at kam dot mff dot cuni dot cz  2007-08-20 12:10 -------
Subject: Re:  Failing to represent the stride (with array) of a dataref when it
is not a constant

> ------- Comment #2 from dorit at gcc dot gnu dot org  2007-08-20 05:55 -------
> > Making us return symbolic stride would not be hard.  The problem is that data
> > dependence analysis would fail anyway, 
> 
> sometimes (not in this testcases) there won't be a need for dependence testing
> - e.g. a reduction computation where there are no stores, or initialization
> with a constant (i.e. a store and no loads), so there's already a value in
> doing this.
> 
> > since we cannot tell whether n is zero.
> 
> can we do the data-dependence analysis conditioned on a maybe_zero (like the
> number-of-iterations analysis)?

possibly a more useful solution would be to teach fortran frontend to use
multidimensional arrays, instead of flattening them to one-dimensional
ones (however, this is also a fairly nontrivial task).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33113