diff options
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index e5ef26f52d3..9bcdcdc1578 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -5372,9 +5372,16 @@ SDValue DAGCombiner::MatchLoadCombine(SDNode *N) { // | D | // Into: // (x & m) | (y & ~m) +// NOTE: we don't unfold the pattern if 'xor' is actually a 'not', because at +// the very least that breaks andnpd / andnps patterns, and because those +// patterns are simplified in IR and shouldn't be created in the DAG SDValue DAGCombiner::unfoldMaskedMerge(SDNode *N) { assert(N->getOpcode() == ISD::XOR); + // Don't touch 'not' (i.e. where y = -1). + if (isAllOnesConstantOrAllOnesSplatConstant(N->getOperand(1))) + return SDValue(); + EVT VT = N->getValueType(0); // FIXME @@ -5392,6 +5399,9 @@ SDValue DAGCombiner::unfoldMaskedMerge(SDNode *N) { return false; SDValue Xor0 = Xor.getOperand(0); SDValue Xor1 = Xor.getOperand(1); + // Don't touch 'not' (i.e. where y = -1). + if (isAllOnesConstantOrAllOnesSplatConstant(Xor1)) + return false; if (Other == Xor0) std::swap(Xor0, Xor1); if (Other != Xor1) |
