diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Target/X86/X86ISelLowering.cpp | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index dfa2a09098..f54b7b6f80 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -8218,6 +8218,18 @@ static SDValue PerformSELECTCombine(SDNode *N, SelectionDAG &DAG, return DAG.getNode(ISD::SHL, DL, LHS.getValueType(), Cond, DAG.getConstant(ShAmt, MVT::i8)); } + + // Optimize Cond ? cst+1 : cst -> zext(setcc(C)+cst. + if (RHSC->getAPIntValue()+1 == LHSC->getAPIntValue()) { + if (NeedsCondInvert) // Invert the condition if needed. + Cond = DAG.getNode(ISD::XOR, DL, Cond.getValueType(), Cond, + DAG.getConstant(1, Cond.getValueType())); + + // Zero extend the condition if needed. + Cond = DAG.getNode(ISD::ZERO_EXTEND, DL, RHSC->getValueType(0), Cond); + return DAG.getNode(ISD::ADD, DL, Cond.getValueType(), Cond, + SDValue(RHSC, 0)); + } } } @@ -8263,6 +8275,21 @@ static SDValue PerformCMOVCombine(SDNode *N, SelectionDAG &DAG, return DCI.CombineTo(N, Cond, SDValue()); return Cond; } + + // Optimize Cond ? cst+1 : cst -> zext(setcc(C)+cst. + if (FalseC->getAPIntValue()+1 == TrueC->getAPIntValue()) { + SDValue Cond = N->getOperand(3); + Cond = DAG.getNode(X86ISD::SETCC, DL, MVT::i8, + DAG.getConstant(CC, MVT::i8), Cond); + + // Zero extend the condition if needed. + Cond = DAG.getNode(ISD::ZERO_EXTEND, DL, FalseC->getValueType(0), Cond); + Cond = DAG.getNode(ISD::ADD, DL, Cond.getValueType(), Cond, + SDValue(FalseC, 0)); + if (N->getNumValues() == 2) // Dead flag value? + return DCI.CombineTo(N, Cond, SDValue()); + return Cond; + } } } return SDValue(); |