[PATCH] D156131: [LV] Generate predicate in a proper VPBasicBlock

[Kolya Panchenko via Phabricator via llvm-commits]

nikolaypanchenko added a comment.

In D156131#4560161 <https://reviews.llvm.org/D156131#4560161>, @fhahn wrote:

> Interesting issue! Would it be possible to construct a test case showing the issue on current `main`?

Unfortunately, I was not able to come up with a test for `main`. I even cannot come up with some nice changeset (clean and robust) to allow this to happen. There're 2 main blockers: masked ordered reduction is not supported by `IVDescriptor`; tail-folding does not support masked reductions.

> Would it be possible to only change the insertion point if need to avoid the issue to avoid many of the test changes?

Similarly, I could not find something simpler. One possible option is to "predict" such transformation by `adjustRecipesForReductions` during masks construction, but that is going to add boilerplate into `createBlockInMask` and `createEdgeMask` functions.


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https://reviews.llvm.org/D156131