diff options
Diffstat (limited to 'lib/CodeGen/CriticalAntiDepBreaker.cpp')
| -rw-r--r-- | lib/CodeGen/CriticalAntiDepBreaker.cpp | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/lib/CodeGen/CriticalAntiDepBreaker.cpp b/lib/CodeGen/CriticalAntiDepBreaker.cpp index 3c7961c2..056e2d5 100644 --- a/lib/CodeGen/CriticalAntiDepBreaker.cpp +++ b/lib/CodeGen/CriticalAntiDepBreaker.cpp @@ -288,9 +288,11 @@ void CriticalAntiDepBreaker::ScanInstruction(MachineInstr *MI, } unsigned -CriticalAntiDepBreaker::findSuitableFreeRegister(unsigned AntiDepReg, +CriticalAntiDepBreaker::findSuitableFreeRegister(MachineInstr *MI, + unsigned AntiDepReg, unsigned LastNewReg, - const TargetRegisterClass *RC) { + const TargetRegisterClass *RC) +{ for (TargetRegisterClass::iterator R = RC->allocation_order_begin(MF), RE = RC->allocation_order_end(MF); R != RE; ++R) { unsigned NewReg = *R; @@ -300,12 +302,16 @@ CriticalAntiDepBreaker::findSuitableFreeRegister(unsigned AntiDepReg, // an anti-dependence with this AntiDepReg, because that would // re-introduce that anti-dependence. if (NewReg == LastNewReg) continue; + // If the instruction already has a def of the NewReg, it's not suitable. + // For example, Instruction with multiple definitions can result in this + // condition. + if (MI->modifiesRegister(NewReg, TRI)) continue; // If NewReg is dead and NewReg's most recent def is not before // AntiDepReg's kill, it's safe to replace AntiDepReg with NewReg. - assert(((KillIndices[AntiDepReg] == ~0u) != (DefIndices[AntiDepReg] == ~0u)) && - "Kill and Def maps aren't consistent for AntiDepReg!"); - assert(((KillIndices[NewReg] == ~0u) != (DefIndices[NewReg] == ~0u)) && - "Kill and Def maps aren't consistent for NewReg!"); + assert(((KillIndices[AntiDepReg] == ~0u) != (DefIndices[AntiDepReg] == ~0u)) + && "Kill and Def maps aren't consistent for AntiDepReg!"); + assert(((KillIndices[NewReg] == ~0u) != (DefIndices[NewReg] == ~0u)) + && "Kill and Def maps aren't consistent for NewReg!"); if (KillIndices[NewReg] != ~0u || Classes[NewReg] == reinterpret_cast<TargetRegisterClass *>(-1) || KillIndices[AntiDepReg] > DefIndices[NewReg]) @@ -336,14 +342,14 @@ BreakAntiDependencies(std::vector<SUnit>& SUnits, #ifndef NDEBUG { - DEBUG(errs() << "Critical path has total latency " + DEBUG(dbgs() << "Critical path has total latency " << (Max->getDepth() + Max->Latency) << "\n"); - DEBUG(errs() << "Available regs:"); + DEBUG(dbgs() << "Available regs:"); for (unsigned Reg = 0; Reg < TRI->getNumRegs(); ++Reg) { if (KillIndices[Reg] == ~0u) - DEBUG(errs() << " " << TRI->getName(Reg)); + DEBUG(dbgs() << " " << TRI->getName(Reg)); } - DEBUG(errs() << '\n'); + DEBUG(dbgs() << '\n'); } #endif @@ -495,10 +501,10 @@ BreakAntiDependencies(std::vector<SUnit>& SUnits, // TODO: Instead of picking the first free register, consider which might // be the best. if (AntiDepReg != 0) { - if (unsigned NewReg = findSuitableFreeRegister(AntiDepReg, + if (unsigned NewReg = findSuitableFreeRegister(MI, AntiDepReg, LastNewReg[AntiDepReg], RC)) { - DEBUG(errs() << "Breaking anti-dependence edge on " + DEBUG(dbgs() << "Breaking anti-dependence edge on " << TRI->getName(AntiDepReg) << " with " << RegRefs.count(AntiDepReg) << " references" << " using " << TRI->getName(NewReg) << "!\n"); |
