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[DAGCombiner] ISD::SDIV/UDIV/SREM/UREM - use general SelectionDAG::FoldConstantArithmetic 

This handles all the constant splat / opaque testing for us.
This commit is contained in:
Simon Pilgrim 2020-01-30 11:49:49 +00:00
parent d242aa245c
commit a967aa2706
1 changed files with 10 additions and 12 deletions
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22
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -3741,13 +3741,14 @@ SDValue DAGCombiner::visitSDIV(SDNode *N) {
SDLoc DL(N);
// fold (sdiv c1, c2) -> c1/c2
ConstantSDNode *N0C = isConstOrConstSplat(N0);
ConstantSDNode *N1C = isConstOrConstSplat(N1);
if (N0C && N1C && !N0C->isOpaque() && !N1C->isOpaque())
return DAG.FoldConstantArithmetic(ISD::SDIV, DL, VT, N0C, N1C);
if (SDValue C = DAG.FoldConstantArithmetic(ISD::SDIV, DL, VT, {N0, N1}))
return C;
// fold (sdiv X, -1) -> 0-X
if (N1C && N1C->isAllOnesValue())
return DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, DL, VT), N0);
// fold (sdiv X, MIN_SIGNED) -> select(X == MIN_SIGNED, 1, 0)
if (N1C && N1C->getAPIntValue().isMinSignedValue())
return DAG.getSelect(DL, VT, DAG.getSetCC(DL, CCVT, N0, N1, ISD::SETEQ),
@ -3885,12 +3886,10 @@ SDValue DAGCombiner::visitUDIV(SDNode *N) {
SDLoc DL(N);
// fold (udiv c1, c2) -> c1/c2
ConstantSDNode *N0C = isConstOrConstSplat(N0);
ConstantSDNode *N1C = isConstOrConstSplat(N1);
if (N0C && N1C)
if (SDValue Folded = DAG.FoldConstantArithmetic(ISD::UDIV, DL, VT,
N0C, N1C))
return Folded;
if (SDValue C = DAG.FoldConstantArithmetic(ISD::UDIV, DL, VT, {N0, N1}))
return C;
// fold (udiv X, -1) -> select(X == -1, 1, 0)
if (N1C && N1C->getAPIntValue().isAllOnesValue())
return DAG.getSelect(DL, VT, DAG.getSetCC(DL, CCVT, N0, N1, ISD::SETEQ),
@ -3983,11 +3982,10 @@ SDValue DAGCombiner::visitREM(SDNode *N) {
SDLoc DL(N);
// fold (rem c1, c2) -> c1%c2
ConstantSDNode *N0C = isConstOrConstSplat(N0);
ConstantSDNode *N1C = isConstOrConstSplat(N1);
if (N0C && N1C)
if (SDValue Folded = DAG.FoldConstantArithmetic(Opcode, DL, VT, N0C, N1C))
return Folded;
if (SDValue C = DAG.FoldConstantArithmetic(Opcode, DL, VT, {N0, N1}))
return C;
// fold (urem X, -1) -> select(X == -1, 0, x)
if (!isSigned && N1C && N1C->getAPIntValue().isAllOnesValue())
return DAG.getSelect(DL, VT, DAG.getSetCC(DL, CCVT, N0, N1, ISD::SETEQ),