Commit 4b04e117 authored by Simon Pilgrim's avatar Simon Pilgrim
Browse files

[DAGCombiner] Sub/SUBSAT - use general SelectionDAG::FoldConstantArithmetic 

This handles all the constant splat / opaque testing for us.
parent 48bd6a09

llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

+7 −10
Original line number Diff line number Diff line
@@ -2976,11 +2976,10 @@ SDValue DAGCombiner::visitSUB(SDNode *N) { 
  // FIXME: Refactor this and xor and other similar operations together.

  if (N0 == N1)

    return tryFoldToZero(DL, TLI, VT, DAG, LegalOperations);

  if (DAG.isConstantIntBuildVectorOrConstantInt(N0) &&

      DAG.isConstantIntBuildVectorOrConstantInt(N1)) {

    // fold (sub c1, c2) -> c1-c2

    return DAG.FoldConstantArithmetic(ISD::SUB, DL, VT, {N0, N1});

  }













  // fold (sub c1, c2) -> c3













  if (SDValue C = DAG.FoldConstantArithmetic(ISD::SUB, DL, VT, {N0, N1}))













    return C;





























  if (SDValue NewSel = foldBinOpIntoSelect(N))















    return NewSel;










@@ -3300,11 +3299,9 @@ SDValue DAGCombiner::visitSUBSAT(SDNode *N) {













  if (N0 == N1)















    return DAG.getConstant(0, DL, VT);



























  if (DAG.isConstantIntBuildVectorOrConstantInt(N0) &&













      DAG.isConstantIntBuildVectorOrConstantInt(N1)) {















  // fold (sub_sat c1, c2) -> c3













    return DAG.FoldConstantArithmetic(N->getOpcode(), DL, VT, {N0, N1});













  }













  if (SDValue C = DAG.FoldConstantArithmetic(N->getOpcode(), DL, VT, {N0, N1}))













    return C;





























  // fold (sub_sat x, 0) -> x















  if (isNullConstant(N1))