diff options
Diffstat (limited to 'lib/CodeGen/RegAllocGreedy.cpp')
-rw-r--r-- | lib/CodeGen/RegAllocGreedy.cpp | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp index 19a9e3182e..6e6a594479 100644 --- a/lib/CodeGen/RegAllocGreedy.cpp +++ b/lib/CodeGen/RegAllocGreedy.cpp @@ -454,12 +454,18 @@ void RAGreedy::enqueue(PQueue &CurQueue, LiveInterval *LI) { // everything else has been allocated. Prio = Size; } else { - if (ExtraRegInfo[Reg].Stage == RS_Assign && !LI->empty() && + // Giant live ranges fall back to the global assignment heuristic, which + // prevents excessive spilling in pathological cases. + bool ReverseLocal = TRI->reverseLocalAssignment(); + bool ForceGlobal = !ReverseLocal && + (Size / SlotIndex::InstrDist) > (2 * MRI->getRegClass(Reg)->getNumRegs()); + + if (ExtraRegInfo[Reg].Stage == RS_Assign && !ForceGlobal && !LI->empty() && LIS->intervalIsInOneMBB(*LI)) { // Allocate original local ranges in linear instruction order. Since they // are singly defined, this produces optimal coloring in the absence of // global interference and other constraints. - if (!TRI->reverseLocalAssignment()) + if (!ReverseLocal) Prio = LI->beginIndex().getInstrDistance(Indexes->getLastIndex()); else { // Allocating bottom up may allow many short LRGs to be assigned first |