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-rw-r--r--llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp12
1 files changed, 0 insertions, 12 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index fdc9f48fbcc..c462a6bcb9f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -7943,18 +7943,6 @@ SDValue DAGCombiner::visitSRL(SDNode *N) {
InnerShift.getOperand(0), NewShiftAmt);
return DAG.getNode(ISD::TRUNCATE, DL, VT, NewShift);
}
- // In the more general case, we can clear the high bits after the shift:
- // srl (trunc (srl x, c1)), c2 --> trunc (and (srl x, (c1+c2)), Mask)
- if (N0.hasOneUse() && InnerShift.hasOneUse() && c1 + c2 <= OpSizeInBits) {
- SDLoc DL(N);
- SDValue NewShiftAmt = DAG.getConstant(c1 + c2, DL, ShiftAmtVT);
- SDValue NewShift = DAG.getNode(ISD::SRL, DL, InnerShiftVT,
- InnerShift.getOperand(0), NewShiftAmt);
- SDValue Mask = DAG.getConstant((1 << (InnerShiftSize - c2)) - 1, DL,
- InnerShiftVT);
- SDValue And = DAG.getNode(ISD::AND, DL, InnerShiftVT, NewShift, Mask);
- return DAG.getNode(ISD::TRUNCATE, DL, VT, And);
- }
}
}
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