[PATCH] D112435: [GlobalISel] Add G_BFI (bitfield insertion opcode)

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


================
Comment at: llvm/lib/CodeGen/MachineVerifier.cpp:1616
+    LLT DstTy = MRI->getType(MI->getOperand(0).getReg());
+    if (DstTy.isVector()) {
+      report("Bitfield insertion is not supported on vectors", MI);
----------------
foad wrote:
> arsenm wrote:
> > arsenm wrote:
> > > paquette wrote:
> > > > Maybe add a FIXME or TODO here noting that it may make sense to extend this to vectors in the future? (I can't think of any use-cases, but maybe it makes sense on some target...)
> > > Supporting on vectors is good for consistency and also can help with combine ordering problems
> > I don't think this should disallow vectors. Having the legalizer scalarize is trivial
> > 
> > I think it's a better question if the second/third operands can be vectors or not
> > I think it's a better question if the second/third operands can be vectors or not
> 
> What are the rules for basic shifts like G_SHL ? I don't see any special handling for them in MachineVerifier. Do we really allow any combination of scalars and vectors for the first and second inputs?
For basic shifts it's all operands vector or all scalar


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  https://reviews.llvm.org/D112435/new/

https://reviews.llvm.org/D112435