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

[Sander de Smalen via Phabricator via llvm-commits]

sdesmalen accepted this revision.
sdesmalen added a comment.
This revision is now accepted and ready to land.

Thanks for all the changes. The patch LGTM with nits addressed.



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Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:4297
+    VPLane Lane = VPLane::getFirstLane();
+    Builder.SetInsertPoint(LoopMiddleBlock->getTerminator());
+    if (isa<Instruction>(IncomingValue) &&
----------------
nit: Did you need to move the call to Builder.SetInsertPoint?


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Comment at: llvm/lib/Transforms/Vectorize/VPlan.cpp:446
          ++Lane) {
-      State->Instance->Lane = Lane;
+      State->Instance->Lane.set(Lane, VPLane::Kind::First);
       // Visit the VPBlocks connected to \p this, starting from it.
----------------
nit: it would be nice if you can write `State->Instance->Lane = VPLane(Lane, VPLane::Kind::First);`
(e.g. by providing `VPLane(const VPlane &Other)` in favour of having a `set` method).


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Comment at: llvm/test/Transforms/LoopVectorize/AArch64/sve-extract-last-veclane.ll:1
+; RUN: opt -loop-vectorize -dce -instcombine -mtriple aarch64-linux-gnu -mattr=+sve -S < %s 2>%t | FileCheck %s
+
----------------
nit: passing the attribute in the command is redundant if it's already set by the IR attributes.


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