diff options
Diffstat (limited to 'lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
-rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 18 |
1 files changed, 2 insertions, 16 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 16ce87a536..3f9b77467d 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -1938,30 +1938,16 @@ SDOperand DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) { return DAG.getNode(ISD::SIGN_EXTEND, VT, Truncate); } - // If the input is already sign extended, just drop the extend. + // If the input is already sign extended, just drop the extension. if (TLI.ComputeNumSignBits(N0) >= MVT::getSizeInBits(VT)-EVTBits+1) return N0; - // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt1 - if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG && - cast<VTSDNode>(N0.getOperand(1))->getVT() <= EVT) { - return N0; - } // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG && EVT < cast<VTSDNode>(N0.getOperand(1))->getVT()) { return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), N1); } - // fold (sext_in_reg (sextload x)) -> (sextload x) - if (N0.getOpcode() == ISD::SEXTLOAD && - cast<VTSDNode>(N0.getOperand(3))->getVT() <= EVT) { - return N0; - } - // fold (sext_in_reg (setcc x)) -> setcc x iff (setcc x) == 0 or -1 - if (N0.getOpcode() == ISD::SETCC && - TLI.getSetCCResultContents() == - TargetLowering::ZeroOrNegativeOneSetCCResult) - return N0; + // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is zero if (TLI.MaskedValueIsZero(N0, 1ULL << (EVTBits-1))) return DAG.getZeroExtendInReg(N0, EVT); |