[llvm] [RISCV] Optimize (slli (srli (slli X, C1), C1), C2) -> (srli (slli X, C1), C1-C2) (PR #119567)

[Piotr Fusik via llvm-commits]

================
@@ -1041,6 +1041,21 @@ void RISCVDAGToDAGISel::Select(SDNode *Node) {
             CurDAG->getTargetConstant(TrailingZeros + ShAmt, DL, VT));
         ReplaceNode(Node, SLLI);
         return;
+      } else if (TrailingZeros == 0 && LeadingZeros > ShAmt &&
----------------
pfusik wrote:

Done

https://github.com/llvm/llvm-project/pull/119567