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[DAGCombiner] visitIMINMAX - use general SelectionDAG::FoldConstantArithmetic 

This handles all the constant splat / opaque testing for us instead of the ConstantSDNode variant where we have to do it ourselves.
This commit is contained in:
Simon Pilgrim 2020-01-29 16:36:03 +00:00
parent e5edd641fd
commit 48bd6a0986
1 changed files with 4 additions and 6 deletions
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10
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -4321,6 +4321,7 @@ SDValue DAGCombiner::visitIMINMAX(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
EVT VT = N0.getValueType();
unsigned Opcode = N->getOpcode();
// fold vector ops
if (VT.isVector())
@ -4328,19 +4329,16 @@ SDValue DAGCombiner::visitIMINMAX(SDNode *N) {
return FoldedVOp;
// fold operation with constant operands.
ConstantSDNode *N0C = getAsNonOpaqueConstant(N0);
ConstantSDNode *N1C = getAsNonOpaqueConstant(N1);
if (N0C && N1C)
return DAG.FoldConstantArithmetic(N->getOpcode(), SDLoc(N), VT, N0C, N1C);
if (SDValue C = DAG.FoldConstantArithmetic(Opcode, SDLoc(N), VT, {N0, N1}))
return C;
// canonicalize constant to RHS
if (DAG.isConstantIntBuildVectorOrConstantInt(N0) &&
!DAG.isConstantIntBuildVectorOrConstantInt(N1))
!DAG.isConstantIntBuildVectorOrConstantInt(N1))
return DAG.getNode(N->getOpcode(), SDLoc(N), VT, N1, N0);
// Is sign bits are zero, flip between UMIN/UMAX and SMIN/SMAX.
// Only do this if the current op isn't legal and the flipped is.
unsigned Opcode = N->getOpcode();
if (!TLI.isOperationLegal(Opcode, VT) &&
(N0.isUndef() || DAG.SignBitIsZero(N0)) &&
(N1.isUndef() || DAG.SignBitIsZero(N1))) {