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[DAGCombiner] ISD::AND/OR/XOR - use general SelectionDAG::FoldConstantArithmetic 

This handles all the constant splat / opaque testing for us.
This commit is contained in:
Simon Pilgrim 2020-01-30 12:02:38 +00:00
parent a967aa2706
commit 57b0d33224
1 changed files with 16 additions and 10 deletions
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26
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -5165,17 +5165,19 @@ SDValue DAGCombiner::visitAND(SDNode *N) {
}
// fold (and c1, c2) -> c1&c2
ConstantSDNode *N0C = getAsNonOpaqueConstant(N0);
ConstantSDNode *N1C = isConstOrConstSplat(N1);
if (N0C && N1C && !N1C->isOpaque())
return DAG.FoldConstantArithmetic(ISD::AND, SDLoc(N), VT, N0C, N1C);
if (SDValue C = DAG.FoldConstantArithmetic(ISD::AND, SDLoc(N), VT, {N0, N1}))
return C;
// canonicalize constant to RHS
if (DAG.isConstantIntBuildVectorOrConstantInt(N0) &&
!DAG.isConstantIntBuildVectorOrConstantInt(N1))
return DAG.getNode(ISD::AND, SDLoc(N), VT, N1, N0);
// fold (and x, -1) -> x
if (isAllOnesConstant(N1))
return N0;
// if (and x, c) is known to be zero, return 0
unsigned BitWidth = VT.getScalarSizeInBits();
if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0),
@ -5866,17 +5868,19 @@ SDValue DAGCombiner::visitOR(SDNode *N) {
}
// fold (or c1, c2) -> c1|c2
ConstantSDNode *N0C = getAsNonOpaqueConstant(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
if (N0C && N1C && !N1C->isOpaque())
return DAG.FoldConstantArithmetic(ISD::OR, SDLoc(N), VT, N0C, N1C);
if (SDValue C = DAG.FoldConstantArithmetic(ISD::OR, SDLoc(N), VT, {N0, N1}))
return C;
// canonicalize constant to RHS
if (DAG.isConstantIntBuildVectorOrConstantInt(N0) &&
!DAG.isConstantIntBuildVectorOrConstantInt(N1))
return DAG.getNode(ISD::OR, SDLoc(N), VT, N1, N0);
// fold (or x, 0) -> x
if (isNullConstant(N1))
return N0;
// fold (or x, -1) -> -1
if (isAllOnesConstant(N1))
return N1;
@ -7021,20 +7025,22 @@ SDValue DAGCombiner::visitXOR(SDNode *N) {
SDLoc DL(N);
if (N0.isUndef() && N1.isUndef())
return DAG.getConstant(0, DL, VT);
// fold (xor x, undef) -> undef
if (N0.isUndef())
return N0;
if (N1.isUndef())
return N1;
// fold (xor c1, c2) -> c1^c2
ConstantSDNode *N0C = getAsNonOpaqueConstant(N0);
ConstantSDNode *N1C = getAsNonOpaqueConstant(N1);
if (N0C && N1C)
return DAG.FoldConstantArithmetic(ISD::XOR, DL, VT, N0C, N1C);
if (SDValue C = DAG.FoldConstantArithmetic(ISD::XOR, DL, VT, {N0, N1}))
return C;
// canonicalize constant to RHS
if (DAG.isConstantIntBuildVectorOrConstantInt(N0) &&
!DAG.isConstantIntBuildVectorOrConstantInt(N1))
return DAG.getNode(ISD::XOR, DL, VT, N1, N0);
// fold (xor x, 0) -> x
if (isNullConstant(N1))
return N0;