- if (SetCCOpcode == ISD::SETULT || SetCCOpcode == ISD::SETUGE) {
- unsigned TrailZeros = RHSC->getAPIntValue().countTrailingZeros();
- if (TrailZeros >= 32) {
- // The constant doesn't fit in cmp immediate field. Right shift LHS by
- // the # of trailing zeros and truncate it to 32-bit. Then compare
- // against shifted RHS.
- assert(LHS.getValueType() == MVT::i64 && "Expecting a 64-bit cmp!");
- DebugLoc dl = LHS.getDebugLoc();
- LHS = DAG.getNode(ISD::TRUNCATE, dl, MVT::i32,
- DAG.getNode(ISD::SRL, dl, MVT::i64, LHS,
- DAG.getConstant(TrailZeros, MVT::i8)));
- uint64_t C = RHSC->getZExtValue() >> TrailZeros;
-
- if (SetCCOpcode == ISD::SETULT) {
- // X < 0x300000000 -> (X >> 32) < 3
- // X < 0x100000000 -> (X >> 32) == 0
- // X < 0x200000000 -> (X >> 33) == 0
- if (C == 1) {
- RHS = DAG.getConstant(0, MVT::i32);
- return X86::COND_E;
- }
- RHS = DAG.getConstant(C, MVT::i32);
- return X86::COND_B;
- } else /* SetCCOpcode == ISD::SETUGE */ {
- // X >= 0x100000000 -> (X >> 32) >= 1
- RHS = DAG.getConstant(C, MVT::i32);
- return X86::COND_AE;
- }
- }
- }
- if (SetCCOpcode == ISD::SETUGT) {
- unsigned TrailOnes = RHSC->getAPIntValue().countTrailingOnes();
- if (TrailOnes >= 32 && !RHSC->isAllOnesValue()) {
- assert(LHS.getValueType() == MVT::i64 && "Expecting a 64-bit cmp!");
- DebugLoc dl = LHS.getDebugLoc();
- LHS = DAG.getNode(ISD::TRUNCATE, dl, MVT::i32,
- DAG.getNode(ISD::SRL, dl, MVT::i64, LHS,
- DAG.getConstant(TrailOnes, MVT::i8)));
- uint64_t C = (RHSC->getZExtValue()+1) >> TrailOnes;
- // X > 0x0ffffffff -> (X >> 32) >= 1
- RHS = DAG.getConstant(C, MVT::i32);
- return X86::COND_AE;
- }
- }