[AArch64][GlobalISel] Legalize ptr shuffle vector to s64 (#116013)
This converts all ptr element shuffle vectors to s64, so that the
existing vector legalization handling can lower them as needed. This
prevents a lot of fallbacks that currently try to generate things like
`<2 x ptr> G_EXT`.
I'm not sure if bitcast/inttoptr/ptrtoint is intended to be necessary
for vectors of pointers, but it uses buildCast for the casts, which now
generates a ptrtoint/inttoptr.
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 062dbbe..321760e 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -3697,6 +3697,41 @@
return Legalized;
}
+// This bitcasts a shuffle vector to a different type currently of the same
+// element size. Mostly used to legalize ptr vectors, where ptrtoint/inttoptr
+// will be used instead.
+//
+// <16 x p0> = G_CONCAT_VECTORS <4 x p0>, <4 x p0>, mask
+// ===>
+// <4 x s64> = G_PTRTOINT <4 x p0>
+// <4 x s64> = G_PTRTOINT <4 x p0>
+// <16 x s64> = G_CONCAT_VECTORS <4 x s64>, <4 x s64>, mask
+// <16 x p0> = G_INTTOPTR <16 x s64>
+LegalizerHelper::LegalizeResult
+LegalizerHelper::bitcastShuffleVector(MachineInstr &MI, unsigned TypeIdx,
+ LLT CastTy) {
+ auto ShuffleMI = cast<GShuffleVector>(&MI);
+ LLT DstTy = MRI.getType(ShuffleMI->getReg(0));
+ LLT SrcTy = MRI.getType(ShuffleMI->getReg(1));
+
+ // We currently only handle vectors of the same size.
+ if (TypeIdx != 0 ||
+ CastTy.getScalarSizeInBits() != DstTy.getScalarSizeInBits() ||
+ CastTy.getElementCount() != DstTy.getElementCount())
+ return UnableToLegalize;
+
+ LLT NewSrcTy = SrcTy.changeElementType(CastTy.getScalarType());
+
+ auto Inp1 = MIRBuilder.buildCast(NewSrcTy, ShuffleMI->getReg(1));
+ auto Inp2 = MIRBuilder.buildCast(NewSrcTy, ShuffleMI->getReg(2));
+ auto Shuf =
+ MIRBuilder.buildShuffleVector(CastTy, Inp1, Inp2, ShuffleMI->getMask());
+ MIRBuilder.buildCast(ShuffleMI->getReg(0), Shuf);
+
+ MI.eraseFromParent();
+ return Legalized;
+}
+
/// This attempts to bitcast G_EXTRACT_SUBVECTOR to CastTy.
///
/// <vscale x 8 x i1> = G_EXTRACT_SUBVECTOR <vscale x 16 x i1>, N
@@ -4133,6 +4168,8 @@
return bitcastInsertVectorElt(MI, TypeIdx, CastTy);
case TargetOpcode::G_CONCAT_VECTORS:
return bitcastConcatVector(MI, TypeIdx, CastTy);
+ case TargetOpcode::G_SHUFFLE_VECTOR:
+ return bitcastShuffleVector(MI, TypeIdx, CastTy);
case TargetOpcode::G_EXTRACT_SUBVECTOR:
return bitcastExtractSubvector(MI, TypeIdx, CastTy);
case TargetOpcode::G_INSERT_SUBVECTOR:
