diff options
Diffstat (limited to 'lib/CodeGen/CriticalAntiDepBreaker.cpp')
| -rw-r--r-- | lib/CodeGen/CriticalAntiDepBreaker.cpp | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/lib/CodeGen/CriticalAntiDepBreaker.cpp b/lib/CodeGen/CriticalAntiDepBreaker.cpp index e5d68a6cb8..056e2d5b01 100644 --- a/lib/CodeGen/CriticalAntiDepBreaker.cpp +++ b/lib/CodeGen/CriticalAntiDepBreaker.cpp @@ -288,7 +288,8 @@ void CriticalAntiDepBreaker::ScanInstruction(MachineInstr *MI, } unsigned -CriticalAntiDepBreaker::findSuitableFreeRegister(unsigned AntiDepReg, +CriticalAntiDepBreaker::findSuitableFreeRegister(MachineInstr *MI, + unsigned AntiDepReg, unsigned LastNewReg, const TargetRegisterClass *RC) { @@ -301,6 +302,10 @@ 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)) @@ -496,7 +501,7 @@ 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(dbgs() << "Breaking anti-dependence edge on " |