[PATCH] D102394: [LoopVectorize] Don't attempt to widen certain calls for scalable vectors

[Sander de Smalen via Phabricator via llvm-commits]

sdesmalen added inline comments.


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Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:5649
+  // Test that the loop-vectorizer can legalize all operations for this VF.
+  // FIXME: While for scalable vectors this is currently sufficient, this should
+  // be replaced by a more detailed mechanism that filters out specific VFs,
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david-arm wrote:
> sdesmalen wrote:
> > Can you move this comment down to the CallInst case?
> Yeah sure, although it's worth pointing out this is an existing comment that was referring to canVectorizeReductions, i.e. that we can also filter out the VFs not valid for the reductions too. I'm happy to move it down to the CallInst case though if you're not worried about the reduction case atm?
Ah I see. Looking at the implementation for canVectorizeReductions, and correspondingly to isLegalToVectorizeReduction, the VF itself isn't really used, so perhaps we may just as well remove it at this point. It's more the reduction-operation that is holding it back from vectorizing rather than the VF. Initially I imagined us having a function like you added here, which would filter the VFs based on capabilities, but it turned out that for the reductions that just wasn't really needed, but we kept the individual VF operand.


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  https://reviews.llvm.org/D102394/new/

https://reviews.llvm.org/D102394