[llvm] [SelectionDAG] Add SelectionDAG::getTypeSize. NFC (PR #169764)

[Sander de Smalen via llvm-commits]

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@@ -2117,13 +2102,24 @@ SDValue SelectionDAG::getVScale(const SDLoc &DL, EVT VT, APInt MulImm,
   return getNode(ISD::VSCALE, DL, VT, getConstant(MulImm, DL, VT));
 }
 
+template <typename Ty>
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sdesmalen-arm wrote:

Can you add documentation for this function to describe what `VT` and `X` mean and how they are used to create the end result?

Also, why does it need to be a templated function? Is that for distinguishing EVT and MVT?

https://github.com/llvm/llvm-project/pull/169764