[PATCH] D79418: [LSR][ARM] Add new TTI hook to mark some LSR chains as profitable

[Sam Parker via Phabricator via llvm-commits]

samparker added a comment.

Looks good. Would you mind also adding a codegen test so we can see this going through the whole pipeline, successfully being tail predicated?



================
Comment at: llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp:2856
+
+  if (TTI.isProfitableLSRChainElement(Chain.Incs[0].UserInst))
+    return true;
----------------
Is this necessary? If this is executed in the loop then I don't see the worth of optimising the first iteration.


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  https://reviews.llvm.org/D79418/new/

https://reviews.llvm.org/D79418