[Polly] Isl AST reduction pragmas [V2]

[Johannes Doerfert]

I think we are getting somewhere (as we are only discussing this one detail), but I'm still not sure where I'm wrong.

>> The dependences for the first program are:
>>
>> {S[i] -> S[i+1]}
>>
>> The dependences for the second program are the same, but the schedule is modified to:
>>
>> {S1[i] -> [0, i]: i % 2 = 0; S1[i] -> [1, i]: i % 2 = 1}

Isn't there still the transitive reduction dependency S[i] --t--> S[i+2] in the same direction as the scheduling dimensions?
If so,  why wouldn't the parallelism test not say "parallel" but "reduction parallel".
If not, please explain why we don't have forward dependences of length 2 here?

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Johannes Doerfert
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation