[PATCH] D102828: [GlobalISel] Implement splitting of G_SHUFFLE_VECTOR.

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


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Comment at: llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp:4231
+  // Further legalization attempts will be needed to do split further.
+  NarrowTy = DstTy.changeNumElements(DstTy.getNumElements() / 2);
+  unsigned NewElts = NarrowTy.getNumElements();
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I don't like simply discarding NarrowTy. It would be better to compute the type you do handle, and fail if it doesn't match the requested type


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Comment at: llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp:4234-4236
+  SmallVector<Register> SplitSrc1Regs, SplitSrc2Regs;
+  extractParts(Src1Reg, NarrowTy, 2, SplitSrc1Regs);
+  extractParts(Src2Reg, NarrowTy, 2, SplitSrc2Regs);
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It should be relatively easy to use extractGCDType + buildLCMMergePieces to form a widened vector for the non-power-of-2 case


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102828/new/

https://reviews.llvm.org/D102828