diff options
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp index e3f2a193..b3f131d 100644 --- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp @@ -5363,10 +5363,25 @@ SDValue TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1, if (AndRHSC.isNegatedPowerOf2() && C1.isSubsetOf(AndRHSC)) { unsigned ShiftBits = AndRHSC.countr_zero(); if (!shouldAvoidTransformToShift(ShValTy, ShiftBits)) { + // If using an unsigned shift doesn't yield a legal compare + // immediate, try using sra instead. + APInt NewC = C1.lshr(ShiftBits); + if (NewC.getSignificantBits() <= 64 && + !isLegalICmpImmediate(NewC.getSExtValue())) { + APInt SignedC = C1.ashr(ShiftBits); + if (SignedC.getSignificantBits() <= 64 && + isLegalICmpImmediate(SignedC.getSExtValue())) { + SDValue Shift = DAG.getNode( + ISD::SRA, dl, ShValTy, N0.getOperand(0), + DAG.getShiftAmountConstant(ShiftBits, ShValTy, dl)); + SDValue CmpRHS = DAG.getConstant(SignedC, dl, ShValTy); + return DAG.getSetCC(dl, VT, Shift, CmpRHS, Cond); + } + } SDValue Shift = DAG.getNode( ISD::SRL, dl, ShValTy, N0.getOperand(0), DAG.getShiftAmountConstant(ShiftBits, ShValTy, dl)); - SDValue CmpRHS = DAG.getConstant(C1.lshr(ShiftBits), dl, ShValTy); + SDValue CmpRHS = DAG.getConstant(NewC, dl, ShValTy); return DAG.getSetCC(dl, VT, Shift, CmpRHS, Cond); } } |