[PATCH] D154075: [LoopVectorize] Add pre-commit tests for D152366

[Florian Hahn via Phabricator via llvm-commits]

fhahn added a comment.

In D154075#4542401 <https://reviews.llvm.org/D154075#4542401>, @david-arm wrote:

> In D154075#4531095 <https://reviews.llvm.org/D154075#4531095>, @fhahn wrote:
>
>> Taking another look, I think we need a few more tests for cases not covered by the current tests:
>
>
>
>> - inner and outer induction incremented by non-constant
>
> I've added the other tests you suggested, but I'm not sure of the value of having tests for non-constant IV increments. For the inner loop a non-constant IV increment will lead to SCEV checks to ensure we only enter the vector loop if the stride is 1, in which case it's going to be a constant anyway. For the outer loop the tests already have outer loop non-constant memory access strides, i.e. tests like this:
>
>   for (int i = m - 1; i >= 0; i--) {
>     for (int j = 0; j <= n; j++) {
>       dst[(i * stride1) + j] += src[(i * stride2) + j];
>    }
>
> where the stride for the outer loop is `stride1` so by making the outer IV increment non-constant all I'm doing is transforming an already unknown stride into another unknown stride, unless I'm missing something?

Thanks for the update, I'll take a closer look in the middle of the week when I am back from traveling.


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