[PATCH] D125994: [NFC] Define move and copy constructors and copy assignment operators for MDOperand.

[Wolfgang Pieb via Phabricator via llvm-commits]

wolfgangp added inline comments.


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Comment at: llvm/include/llvm/IR/Metadata.h:782
+  }
+  MDOperand(const MDOperand &Op) {
+    MD = Op.MD;
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dexonsmith wrote:
> I don’t think we need this and it seems better to error here. I think we should keep the copy constructor/operator deleted and make this move-only.
In that case I'm a bit stuck because the implementation of SmallVector uses std::fill_n() and std::uninitialized_fill_n() which assign and copy the value type and want the copy constructor (at least on gcc-9). Do you have any suggestions of should we roll our own hung-off storage class after all? 


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Comment at: llvm/include/llvm/IR/Metadata.h:793
   }
   void reset(Metadata *MD, Metadata *Owner) {
     untrack();
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dexonsmith wrote:
> Looking at this, is it even safe to use the standard move operators? Seems like you don’t have a way to pass in the owner…
IIUC (and I might be wrong there), only operands of uniqued nodes have an owner? Since we're only resizing non-uniqued nodes it seems it would probably work but how would one enforce the destination node always being non-uniqued?


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  https://reviews.llvm.org/D125994/new/

https://reviews.llvm.org/D125994