[PATCH] D95139: [SVE][LoopVectorize] Add support for extracting the last lane of a scalable vector

[Sander de Smalen via Phabricator via llvm-commits]

sdesmalen added inline comments.


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Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:2943
         (Cost->isUniformAfterVectorization(Operand, State.VF)))
-      InputInstance.Lane = 0;
+      InputInstance.Lane.set(0, VPLane::Kind::First);
     auto *NewOp = State.get(User.getOperand(op), InputInstance);
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nit: maybe add a `static VPIteration::getFirstLane`? (seems to be useful in several places).


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Comment at: llvm/lib/Transforms/Vectorize/VPlan.cpp:239
+    return Data
+        .PerPartScalars[Def][Instance.Part][Instance.Lane.getKnownLane()];
 
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should this use `mapToCacheIndex` ?


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Comment at: llvm/lib/Transforms/Vectorize/VPlan.h:185
 
-  VPIteration(unsigned Part, unsigned Lane) : Part(Part), Lane(Lane) {}
+  VPIteration(unsigned Part, VPLane Lane) : Part(Part), Lane(Lane) {}
 
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nit: `const VPLane &`


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Comment at: llvm/lib/Transforms/Vectorize/VPlan.h:187
 
-  bool isFirstIteration() const { return Part == 0 && Lane == 0; }
+  bool isFirstIteration() const { return Part == 0 && Lane.isFirstLane(); }
 };
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nit: is `isFirstIteration` unused now?


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  https://reviews.llvm.org/D95139/new/

https://reviews.llvm.org/D95139