[DAGCombine] Address review comments

dtcxzyw · dtcxzyw · commit 728dad36745c · 2024-04-11T22:30:59.000+08:00
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -9986,7 +9986,7 @@ SDValue DAGCombiner::visitSHL(SDNode *N) {
       TLI.isOperationLegalOrCustom(ISD::MUL, VT)) {
     SDValue Y = N1.getOperand(0);
     SDLoc DL(N);
-    SDValue NegY = DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, DL, VT), Y);
+    SDValue NegY = DAG.getNegative(Y, DL, VT);
     SDValue And = DAG.getNode(ISD::AND, DL, VT, Y, NegY);
     return DAG.getNode(ISD::MUL, DL, VT, And, N0);
   }

Original file line number	Diff line number	Diff line change
`@@ -9986,7 +9986,7 @@ SDValue DAGCombiner::visitSHL(SDNode *N) {`
`9986`	`9986`	`TLI.isOperationLegalOrCustom(ISD::MUL, VT)) {`
`9987`	`9987`	`SDValue Y = N1.getOperand(0);`
`9988`	`9988`	`SDLoc DL(N);`
`9989`		`- SDValue NegY = DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, DL, VT), Y);`
	`9989`	`+ SDValue NegY = DAG.getNegative(Y, DL, VT);`
`9990`	`9990`	`SDValue And = DAG.getNode(ISD::AND, DL, VT, Y, NegY);`
`9991`	`9991`	`return DAG.getNode(ISD::MUL, DL, VT, And, N0);`
`9992`	`9992`	`}`