[PATCH] D126201: [WIP] Very early work to enable isel of fixed length vector extracts from scalable vectors.

[Allen zhong via Phabricator via llvm-commits]

Allen added inline comments.


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Comment at: llvm/include/llvm/Target/TargetSelectionDAG.td:272
+def SDTSubVecExtract2 : SDTypeProfile<1, 2, [// subvector extract
+    SDTCisVec<0>, SDTCisVec<1>, SDTCisInt<2>
+]>;
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hi @paulwalker-arm:
   I'm not familiar with the def, do you mean **SDTCisVec<0>** and **SDTCisInt<2>** have different type, so this is guard with **A.isScalable() != B.isScalable() **? thanks.


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Comment at: llvm/lib/Target/AArch64/AArch64SVEInstrInfo.td:1425
 
+  // Extract fixed length subvector from FP SVE vectors
+  def : Pat<(v2f32 (extract_subvector2 (nxv2f32 ZPR:$Zs), (i64 0))),
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hi, @paulwalker-arm:
   do you still working on it, may be it need more pattern to match above commented pattten?


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D126201/new/

https://reviews.llvm.org/D126201