[llvm] [NVPTX] Implement computeKnownBitsForTargetNode for LoadV2/4 (PR #154165)

[Alex MacLean via llvm-commits]

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@@ -6609,6 +6537,27 @@ static void computeKnownBitsForPRMT(const SDValue Op, KnownBits &Known,
   }
 }
 
+static void computeKnownBitsFori8VLoad(const SDValue Op, KnownBits &Known) {
+  MemSDNode *Mem = dyn_cast<MemSDNode>(Op);
+  if (!Mem) {
+    return;
+  }
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AlexMaclean wrote:

Just use a `cast` here as we never expect it not to be a `MemSDNode`

https://github.com/llvm/llvm-project/pull/154165