diff options
Diffstat (limited to 'lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 42 |
1 files changed, 27 insertions, 15 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp index f43c4e4e7e..fd8fe22f61 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -1557,29 +1557,41 @@ void SelectionDAGBuilder::visitBitTestCase(MachineBasicBlock* NextMBB, unsigned Reg, BitTestCase &B, MachineBasicBlock *SwitchBB) { - // Make desired shift SDValue ShiftOp = DAG.getCopyFromReg(getControlRoot(), getCurDebugLoc(), Reg, TLI.getPointerTy()); - SDValue SwitchVal = DAG.getNode(ISD::SHL, getCurDebugLoc(), - TLI.getPointerTy(), - DAG.getConstant(1, TLI.getPointerTy()), - ShiftOp); - - // Emit bit tests and jumps - SDValue AndOp = DAG.getNode(ISD::AND, getCurDebugLoc(), - TLI.getPointerTy(), SwitchVal, - DAG.getConstant(B.Mask, TLI.getPointerTy())); - SDValue AndCmp = DAG.getSetCC(getCurDebugLoc(), - TLI.getSetCCResultType(AndOp.getValueType()), - AndOp, DAG.getConstant(0, TLI.getPointerTy()), - ISD::SETNE); + SDValue Cmp; + if (CountPopulation_64(B.Mask) == 1) { + // Testing for a single bit; just compare the shift count with what it + // would need to be to shift a 1 bit in that position. + Cmp = DAG.getSetCC(getCurDebugLoc(), + TLI.getSetCCResultType(ShiftOp.getValueType()), + ShiftOp, + DAG.getConstant(CountTrailingZeros_64(B.Mask), + TLI.getPointerTy()), + ISD::SETEQ); + } else { + // Make desired shift + SDValue SwitchVal = DAG.getNode(ISD::SHL, getCurDebugLoc(), + TLI.getPointerTy(), + DAG.getConstant(1, TLI.getPointerTy()), + ShiftOp); + + // Emit bit tests and jumps + SDValue AndOp = DAG.getNode(ISD::AND, getCurDebugLoc(), + TLI.getPointerTy(), SwitchVal, + DAG.getConstant(B.Mask, TLI.getPointerTy())); + Cmp = DAG.getSetCC(getCurDebugLoc(), + TLI.getSetCCResultType(AndOp.getValueType()), + AndOp, DAG.getConstant(0, TLI.getPointerTy()), + ISD::SETNE); + } SwitchBB->addSuccessor(B.TargetBB); SwitchBB->addSuccessor(NextMBB); SDValue BrAnd = DAG.getNode(ISD::BRCOND, getCurDebugLoc(), MVT::Other, getControlRoot(), - AndCmp, DAG.getBasicBlock(B.TargetBB)); + Cmp, DAG.getBasicBlock(B.TargetBB)); // Set NextBlock to be the MBB immediately after the current one, if any. // This is used to avoid emitting unnecessary branches to the next block. |