Index: lib/Target/PowerPC/PPCInstrInfo.cpp =================================================================== --- lib/Target/PowerPC/PPCInstrInfo.cpp +++ lib/Target/PowerPC/PPCInstrInfo.cpp @@ -1738,25 +1738,32 @@ MachineInstr *UseMI = &*MRI->use_instr_begin(CRReg); if (UseMI->getOpcode() == PPC::BCC) { PPC::Predicate Pred = (PPC::Predicate)UseMI->getOperand(0).getImm(); + PPC::Predicate NewPred = Pred; unsigned PredCond = PPC::getPredicateCondition(Pred); unsigned PredHint = PPC::getPredicateHint(Pred); int16_t Immed = (int16_t)Value; // When modyfing the condition in the predicate, we propagate hint bits // from the original predicate to the new one. - if (Immed == -1 && PredCond == PPC::PRED_GT) { + if (Immed == -1 && PredCond == PPC::PRED_GT) // We convert "greater than -1" into "greater than or equal to 0", // since we are assuming signed comparison by !equalityOnly - PredsToUpdate.push_back(std::make_pair(&(UseMI->getOperand(0)), - PPC::getPredicate(PPC::PRED_GE, PredHint))); - Success = true; - } - else if (Immed == 1 && PredCond == PPC::PRED_LT) { + NewPred = PPC::getPredicate(PPC::PRED_GE, PredHint); + else if (Immed == -1 && PredCond == PPC::PRED_LE) + // We convert "less than or equal to -1" into "less than 0". + NewPred = PPC::getPredicate(PPC::PRED_LT, PredHint); + else if (Immed == 1 && PredCond == PPC::PRED_LT) // We convert "less than 1" into "less than or equal to 0". - PredsToUpdate.push_back(std::make_pair(&(UseMI->getOperand(0)), - PPC::getPredicate(PPC::PRED_LE, PredHint))); - Success = true; - } + NewPred = PPC::getPredicate(PPC::PRED_LE, PredHint); + else if (Immed == 1 && PredCond == PPC::PRED_GE) + // We convert "greater than or equal to 1" into "greater than 0". + NewPred = PPC::getPredicate(PPC::PRED_GT, PredHint); + else + return false; + + PredsToUpdate.push_back(std::make_pair(&(UseMI->getOperand(0)), + NewPred)); + Success = true; } } Index: test/CodeGen/PowerPC/opt-cmp-inst-cr0-live.ll =================================================================== --- test/CodeGen/PowerPC/opt-cmp-inst-cr0-live.ll +++ test/CodeGen/PowerPC/opt-cmp-inst-cr0-live.ll @@ -78,3 +78,36 @@ } declare void @exit(i32 signext) + + +; CHECK-LABEL: fn5 +define i8* @fn5(i8* readonly %p) { +; CHECK: LBZU +; CHECK: EXTSBo +; CHECK-NOT: CMP +; CHECK: BCC 12 +; CHECK: LBZU +; CHECK: EXTSBo +; CHECK-NOT: CMP +; CHECK: BCC 4 + +entry: + %incdec.ptr = getelementptr inbounds i8, i8* %p, i64 -1 + %0 = load i8, i8* %incdec.ptr + %cmp = icmp sgt i8 %0, -1 + br i1 %cmp, label %out, label %if.end + +if.end: + %incdec.ptr2 = getelementptr inbounds i8, i8* %p, i64 -2 + %1 = load i8, i8* %incdec.ptr2 + %cmp4 = icmp sgt i8 %1, -1 + br i1 %cmp4, label %out, label %cleanup + +out: + %p.addr.0 = phi i8* [ %incdec.ptr, %entry ], [ %incdec.ptr2, %if.end ] + br label %cleanup + +cleanup: + %retval.0 = phi i8* [ %p.addr.0, %out ], [ null, %if.end ] + ret i8* %retval.0 +}