[llvm] [PowerPC] Replace vspltisw+vadduwm instructions with xxleqv+vsubuwm for adding the vector {1, 1, 1, 1} (PR #160882)

[Tony Varghese via llvm-commits]

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@@ -19208,13 +19208,54 @@ static SDValue combineADDToMAT_PCREL_ADDR(SDNode *N, SelectionDAG &DAG,
   return MatPCRel;
 }
 
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tonykuttai wrote:

Add a comment block explaining what this function is doing.

https://github.com/llvm/llvm-project/pull/160882