[PATCH] D75452: [ARM][MVE] Validate tail predication values

[Sam Parker via Phabricator via llvm-commits]

samparker marked an inline comment as done.
samparker added a comment.

> do we have test where lanes are swapped (if that makes sense)?

I don't think there's one for this pass... but that was the reason for having a unit test for validForTailPredication, so we don't have to write a whole loop to test an instruction.



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Comment at: llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp:582
+    // Only evaluate instructions which produce a single value.
+    if (MI.getNumDefs() != 1 || !MI.defs().begin()->isReg()) {
+      UnknownFalseLanes.insert(&MI);
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SjoerdMeijer wrote:
> Is there a test for this?
The only instructions that I can think of would be indexed load/stores, but they'll be caught by isVectorPredicated. If/When we can enable reductions, we could have an instruction producing two scalar values and then this logic will need to be reorganised a bit.


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https://reviews.llvm.org/D75452