[llvm] [RISCV] Support 3-argument associative add for transformAddShlImm (PR #86883)

[Craig Topper via llvm-commits]

================
@@ -12733,20 +12733,13 @@ static SDValue combineBinOpToReduce(SDNode *N, SelectionDAG &DAG,
 
 // Optimize (add (shl x, c0), (shl y, c1)) ->
 //          (SLLI (SH*ADD x, y), c0), if c1-c0 equals to [1|2|3].
-static SDValue transformAddShlImm(SDNode *N, SelectionDAG &DAG,
+static SDValue transformAddShlImm(SDValue N0, SDValue N1, SDLoc DL,
----------------
topperc wrote:

SDLoc should be passed by reference

https://github.com/llvm/llvm-project/pull/86883