[PATCH] [Polly] Extract number of elements/iterations for a isl_set/isl_ast_node

Tobias Grosser tobias at grosser.es
Fri Oct 10 07:18:17 PDT 2014

On 10.10.2014 16:09, Sven Verdoolaege wrote:
> On Fri, Oct 10, 2014 at 12:45:31PM +0200, Tobias Grosser wrote:
>> We can get the split up schedule from isl_ast_build, but I am still afraid
>> that we may not be able to derive from this a precise answer. Specifically,
>> the AST generator may avoid the generation of certain conditions in the
>> outer loops relying on the inner loop to filter them out, no?
> That partial schedule only tells you something about the schedule dimensions
> for which no AST nodes have been generated so far.  It doesn't tell you anything
> about those for which nodes have already been generated.
>> Do you happen to have an idea if/how to implement it there? Or are you
> You should check if loop condition holding for the initial value
> is implied by the generated constraints.
> The first set can be constructed in a way that is similar to how
> the enforced set in constructed, except that the enforced set
> is a superset of the set you want.

Johannes, it seems that what would need to be added to isl to understand 
if a loop is executed at least once. Feel free to give it a shot.


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