[llvm] Introducing a new ISD::POISON SDNode to represent the poison value in the IR. (PR #125883)

[Amy Kwan via llvm-commits]

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@@ -1130,6 +1130,9 @@ class SelectionDAG {
     return getNode(ISD::UNDEF, SDLoc(), VT);
   }
 
+  /// Return an POISON node. POISON does not have a useful SDLoc.
+  SDValue getPoison(EVT VT) { return getNode(ISD::POISON, SDLoc(), VT); }
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amy-kwan wrote:

nit: Maybe since we're getting the actual ISD::POISIN, we should call it `getPOISON()` similar to the other nodes that get the actual ISD node?

https://github.com/llvm/llvm-project/pull/125883