[PATCH] D146199: [LoopVectorize] Don't tail-fold for scalable VFs when there is no scalar tail

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added inline comments.


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Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:5161
+  // we choose.
+  std::optional<unsigned> MaxPowerOf2RuntimeVF =
+      MaxFactors.FixedVF.getFixedValue();
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sdesmalen wrote:
> ABataev wrote:
> > Looks like this std::optional does not work here, because MaxFactors.FixedVF.getFixedValue() returns non_optional value. So it may crash in the assert in line 5174, if MaxFactors.FixedVF.getFixedValue() returns 0 and MaxFactors.ScalableVF is not set.
> My understanding is that normally (when not forcing it through an option) MaxFactors.FixedVF will be >= 1, are you saying that is not the case? I agree it's worth adding an extra check.
It might be 0 too


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https://reviews.llvm.org/D146199