[llvm] [AArch64] Combine vector add(trunc(shift)) (PR #169523)

[Sam Tebbs via llvm-commits]

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@@ -22595,6 +22596,37 @@ static SDValue performSubWithBorrowCombine(SDNode *N, SelectionDAG &DAG) {
                      Flags);
 }
 
+// add(trunc(ashr(A, C)), trunc(lshr(B, BW-1))), with C >= BW
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SamTebbs33 wrote:

Should `B` here be `A`? That seems to be what the code suggests.

https://github.com/llvm/llvm-project/pull/169523