diff options
Diffstat (limited to 'llvm/lib/CodeGen/RegAllocGreedy.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/RegAllocGreedy.cpp | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/RegAllocGreedy.cpp b/llvm/lib/CodeGen/RegAllocGreedy.cpp index 07b201bdf18..e8e6cf21f1c 100644 --- a/llvm/lib/CodeGen/RegAllocGreedy.cpp +++ b/llvm/lib/CodeGen/RegAllocGreedy.cpp @@ -125,6 +125,11 @@ static cl::opt<bool> EnableDeferredSpilling( "variable because of other evicted variables."), cl::init(false)); +static cl::opt<unsigned> + HugeSizeForSplit("huge-size-for-split", cl::Hidden, + cl::desc("Last chance recoloring max depth"), + cl::init(5000)); + // FIXME: Find a good default for this flag and remove the flag. static cl::opt<unsigned> CSRFirstTimeCost("regalloc-csr-first-time-cost", @@ -478,6 +483,7 @@ private: SmallVectorImpl<unsigned>&, unsigned = ~0u); unsigned tryRegionSplit(LiveInterval&, AllocationOrder&, SmallVectorImpl<unsigned>&); + unsigned isSplitBenefitWorthCost(LiveInterval &VirtReg); /// Calculate cost of region splitting. unsigned calculateRegionSplitCost(LiveInterval &VirtReg, AllocationOrder &Order, @@ -1771,8 +1777,21 @@ void RAGreedy::splitAroundRegion(LiveRangeEdit &LREdit, MF->verify(this, "After splitting live range around region"); } +// Global split has high compile time cost especially for large live range. +// Return false for the case here where the potential benefit will never +// worth the cost. +unsigned RAGreedy::isSplitBenefitWorthCost(LiveInterval &VirtReg) { + MachineInstr *MI = MRI->getUniqueVRegDef(VirtReg.reg); + if (MI && TII->isTriviallyReMaterializable(*MI, AA) && + VirtReg.size() > HugeSizeForSplit) + return false; + return true; +} + unsigned RAGreedy::tryRegionSplit(LiveInterval &VirtReg, AllocationOrder &Order, SmallVectorImpl<unsigned> &NewVRegs) { + if (!isSplitBenefitWorthCost(VirtReg)) + return 0; unsigned NumCands = 0; BlockFrequency SpillCost = calcSpillCost(); BlockFrequency BestCost; |
