[llvm] [DAGCombiner] Fold smax(X, -1)/smin(X, 0) to bitwise shift forms (PR #206242)

[Matt Arsenault via llvm-commits]

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@@ -6321,14 +6321,14 @@ SDValue DAGCombiner::visitIMINMAX(SDNode *N) {
   if (TLI.isTypeLegal(VT) &&
       !TLI.shouldAvoidTransformToShift(VT, VT.getScalarSizeInBits() - 1)) {
     if (Opcode == ISD::SMAX && TLI.isOperationExpand(ISD::SMAX, VT) &&
-        N0.getOpcode() != ISD::SMIN && isAllOnesConstant(N1)) {
+        N0.getOpcode() != ISD::SMIN && sd_match(N1, m_AllOnes())) {
       SDValue ShiftAmt =
           DAG.getShiftAmountConstant(VT.getScalarSizeInBits() - 1, VT, DL);
       SDValue Shift = DAG.getNode(ISD::SRA, DL, VT, N0, ShiftAmt);
       return DAG.getNode(ISD::OR, DL, VT, N0, Shift);
     }
     if (Opcode == ISD::SMIN && TLI.isOperationExpand(ISD::SMIN, VT) &&
-        N0.getOpcode() != ISD::SMAX && isNullConstant(N1)) {
+        N0.getOpcode() != ISD::SMAX && sd_match(N1, m_Zero())) {
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arsenm wrote:

I meant one sd_match instant on the constant, and then check the requesting const APInt * here and above 

https://github.com/llvm/llvm-project/pull/206242