diff options
| -rw-r--r-- | include/llvm/CodeGen/RegisterPressure.h | 4 | ||||
| -rw-r--r-- | lib/CodeGen/MachineScheduler.cpp | 40 |
2 files changed, 36 insertions, 8 deletions
diff --git a/include/llvm/CodeGen/RegisterPressure.h b/include/llvm/CodeGen/RegisterPressure.h index 2670180..bbc8ca5 100644 --- a/include/llvm/CodeGen/RegisterPressure.h +++ b/include/llvm/CodeGen/RegisterPressure.h @@ -99,6 +99,10 @@ struct PressureElement { PressureElement(unsigned id, int inc): PSetID(id), UnitIncrease(inc) {} bool isValid() const { return PSetID != ~0U; } + + // If signed PSetID is negative, it is invalid; convert it to INT_MAX to give + // it lowest priority. + int PSetRank() const { return PSetID & INT_MAX; } }; /// Store the effects of a change in pressure on things that MI scheduler cares diff --git a/lib/CodeGen/MachineScheduler.cpp b/lib/CodeGen/MachineScheduler.cpp index 19e86d7..4e3cc3c 100644 --- a/lib/CodeGen/MachineScheduler.cpp +++ b/lib/CodeGen/MachineScheduler.cpp @@ -2024,6 +2024,30 @@ static bool tryGreater(int TryVal, int CandVal, return false; } +static bool tryPressure(const PressureElement &TryP, + const PressureElement &CandP, + ConvergingScheduler::SchedCandidate &TryCand, + ConvergingScheduler::SchedCandidate &Cand, + ConvergingScheduler::CandReason Reason) { + // If both candidates affect the same set, go with the smallest increase. + if (TryP.PSetID == CandP.PSetID) { + return tryLess(TryP.UnitIncrease, CandP.UnitIncrease, TryCand, Cand, + Reason); + } + // If one candidate decreases and the other increases, go with it. + if (tryLess(TryP.UnitIncrease < 0, CandP.UnitIncrease < 0, TryCand, Cand, + Reason)) { + return true; + } + // If TryP has lower Rank, it has a higher priority. + int TryRank = TryP.PSetRank(); + int CandRank = CandP.PSetRank(); + // If the candidates are decreasing pressure, reverse priority. + if (TryP.UnitIncrease < 0) + std::swap(TryRank, CandRank); + return tryGreater(TryRank, CandRank, TryCand, Cand, Reason); +} + static unsigned getWeakLeft(const SUnit *SU, bool isTop) { return (isTop) ? SU->WeakPredsLeft : SU->WeakSuccsLeft; } @@ -2089,15 +2113,15 @@ void ConvergingScheduler::tryCandidate(SchedCandidate &Cand, TryCand, Cand, PhysRegCopy)) return; - // Avoid exceeding the target's limit. - if (tryLess(TryCand.RPDelta.Excess.UnitIncrease, - Cand.RPDelta.Excess.UnitIncrease, TryCand, Cand, RegExcess)) + // Avoid exceeding the target's limit. If signed PSetID is negative, it is + // invalid; convert it to INT_MAX to give it lowest priority. + if (tryPressure(TryCand.RPDelta.Excess, Cand.RPDelta.Excess, TryCand, Cand, + RegExcess)) return; // Avoid increasing the max critical pressure in the scheduled region. - if (tryLess(TryCand.RPDelta.CriticalMax.UnitIncrease, - Cand.RPDelta.CriticalMax.UnitIncrease, - TryCand, Cand, RegCritical)) + if (tryPressure(TryCand.RPDelta.CriticalMax, Cand.RPDelta.CriticalMax, + TryCand, Cand, RegCritical)) return; // Keep clustered nodes together to encourage downstream peephole @@ -2119,8 +2143,8 @@ void ConvergingScheduler::tryCandidate(SchedCandidate &Cand, return; } // Avoid increasing the max pressure of the entire region. - if (tryLess(TryCand.RPDelta.CurrentMax.UnitIncrease, - Cand.RPDelta.CurrentMax.UnitIncrease, TryCand, Cand, RegMax)) + if (tryPressure(TryCand.RPDelta.CurrentMax, Cand.RPDelta.CurrentMax, + TryCand, Cand, RegMax)) return; // Avoid critical resource consumption and balance the schedule. |