Sink DwarfDebug::attachLowHighPC into DwarfCompileUnit

[oota-llvm.git] / lib / CodeGen / RegAllocGreedy.cpp

diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index e65398f592dcaab3739caa057f67fb397c312703..223c5e159a780ac87684ac7174eaf8e9135ef7f8 100644 (file)
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -12,7 +12,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "regalloc"
 #include "llvm/CodeGen/Passes.h"
 #include "AllocationOrder.h"
 #include "InterferenceCache.h"
@@ -45,10 +44,13 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
 #include <queue>
 
 using namespace llvm;
 
+#define DEBUG_TYPE "regalloc"
+
 STATISTIC(NumGlobalSplits, "Number of split global live ranges");
 STATISTIC(NumLocalSplits,  "Number of split local live ranges");
 STATISTIC(NumEvicted,      "Number of interferences evicted");
@@ -73,6 +75,17 @@ static cl::opt<unsigned> LastChanceRecoloringMaxInterference(
              " interference at a time"),
     cl::init(8));
 
+static cl::opt<bool>
+ExhaustiveSearch("exhaustive-register-search", cl::NotHidden,
+                 cl::desc("Exhaustive Search for registers bypassing the depth "
+                          "and interference cutoffs of last chance recoloring"));
+
+static cl::opt<bool> EnableLocalReassignment(
+    "enable-local-reassign", cl::Hidden,
+    cl::desc("Local reassignment can yield better allocation decisions, but "
+             "may be compile time intensive"),
+    cl::init(false));
+
 // FIXME: Find a good default for this flag and remove the flag.
 static cl::opt<unsigned>
 CSRFirstTimeCost("regalloc-csr-first-time-cost",
@@ -279,6 +292,10 @@ class RAGreedy : public MachineFunctionPass,
   /// Callee-save register cost, calculated once per machine function.
   BlockFrequency CSRCost;
 
+  /// Run or not the local reassignment heuristic. This information is
+  /// obtained from the TargetSubtargetInfo.
+  bool EnableLocalReassign;
+
 public:
   RAGreedy();
 
@@ -469,7 +486,7 @@ void RAGreedy::LRE_DidCloneVirtReg(unsigned New, unsigned Old) {
 }
 
 void RAGreedy::releaseMemory() {
-  SpillerInstance.reset(0);
+  SpillerInstance.reset();
   ExtraRegInfo.clear();
   GlobalCand.clear();
 }
@@ -497,7 +514,7 @@ void RAGreedy::enqueue(PQueue &CurQueue, LiveInterval *LI) {
     // Giant live ranges fall back to the global assignment heuristic, which
     // prevents excessive spilling in pathological cases.
     bool ReverseLocal = TRI->reverseLocalAssignment();
-    bool ForceGlobal = !ReverseLocal && TRI->mayOverrideLocalAssignment() &&
+    bool ForceGlobal = !ReverseLocal &&
       (Size / SlotIndex::InstrDist) > (2 * MRI->getRegClass(Reg)->getNumRegs());
 
     if (ExtraRegInfo[Reg].Stage == RS_Assign && !ForceGlobal && !LI->empty() &&
@@ -536,7 +553,7 @@ LiveInterval *RAGreedy::dequeue() { return dequeue(Queue); }
 
 LiveInterval *RAGreedy::dequeue(PQueue &CurQueue) {
   if (CurQueue.empty())
-    return 0;
+    return nullptr;
   LiveInterval *LI = &LIS->getInterval(~CurQueue.top().second);
   CurQueue.pop();
   return LI;
@@ -725,7 +742,7 @@ bool RAGreedy::canEvictInterference(LiveInterval &VirtReg, unsigned PhysReg,
       // Evicting another local live range in this case could lead to suboptimal
       // coloring.
       if (!MaxCost.isMax() && IsLocal && LIS->intervalIsInOneMBB(*Intf) &&
-          !canReassign(*Intf, PhysReg)) {
+          (!EnableLocalReassign || !canReassign(*Intf, PhysReg))) {
         return false;
       }
     }
@@ -950,14 +967,12 @@ void RAGreedy::addThroughConstraints(InterferenceCache::Cursor Intf,
       BCS[B].Exit = SpillPlacement::PrefSpill;
 
     if (++B == GroupSize) {
-      ArrayRef<SpillPlacement::BlockConstraint> Array(BCS, B);
-      SpillPlacer->addConstraints(Array);
+      SpillPlacer->addConstraints(makeArrayRef(BCS, B));
       B = 0;
     }
   }
 
-  ArrayRef<SpillPlacement::BlockConstraint> Array(BCS, B);
-  SpillPlacer->addConstraints(Array);
+  SpillPlacer->addConstraints(makeArrayRef(BCS, B));
   SpillPlacer->addLinks(makeArrayRef(TBS, T));
 }
 
@@ -996,7 +1011,7 @@ void RAGreedy::growRegion(GlobalSplitCandidate &Cand) {
 
     // Compute through constraints from the interference, or assume that all
     // through blocks prefer spilling when forming compact regions.
-    ArrayRef<unsigned> NewBlocks = makeArrayRef(ActiveBlocks).slice(AddedTo);
+    auto NewBlocks = makeArrayRef(ActiveBlocks).slice(AddedTo);
     if (Cand.PhysReg)
       addThroughConstraints(Cand.Intf, NewBlocks);
     else
@@ -1932,7 +1947,7 @@ RAGreedy::mayRecolorAllInterferences(unsigned PhysReg, LiveInterval &VirtReg,
     // If there is LastChanceRecoloringMaxInterference or more interferences,
     // chances are one would not be recolorable.
     if (Q.collectInterferingVRegs(LastChanceRecoloringMaxInterference) >=
-        LastChanceRecoloringMaxInterference) {
+        LastChanceRecoloringMaxInterference && !ExhaustiveSearch) {
       DEBUG(dbgs() << "Early abort: too many interferences.\n");
       CutOffInfo |= CO_Interf;
       return false;
@@ -2005,7 +2020,7 @@ unsigned RAGreedy::tryLastChanceRecoloring(LiveInterval &VirtReg,
   // We may want to reconsider that if we end up with a too large search space
   // for target with hundreds of registers.
   // Indeed, in that case we may want to cut the search space earlier.
-  if (Depth >= LastChanceRecoloringMaxDepth) {
+  if (Depth >= LastChanceRecoloringMaxDepth && !ExhaustiveSearch) {
     DEBUG(dbgs() << "Abort because max depth has been reached.\n");
     CutOffInfo |= CO_Depth;
     return ~0u;
@@ -2139,14 +2154,17 @@ unsigned RAGreedy::selectOrSplit(LiveInterval &VirtReg,
   if (Reg == ~0U && (CutOffInfo != CO_None)) {
     uint8_t CutOffEncountered = CutOffInfo & (CO_Depth | CO_Interf);
     if (CutOffEncountered == CO_Depth)
-      Ctx.emitError(
-          "register allocation failed: maximum depth for recoloring reached");
+      Ctx.emitError("register allocation failed: maximum depth for recoloring "
+                    "reached. Use -fexhaustive-register-search to skip "
+                    "cutoffs");
     else if (CutOffEncountered == CO_Interf)
       Ctx.emitError("register allocation failed: maximum interference for "
-                    "recoloring reached");
+                    "recoloring reached. Use -fexhaustive-register-search "
+                    "to skip cutoffs");
     else if (CutOffEncountered == (CO_Depth | CO_Interf))
       Ctx.emitError("register allocation failed: maximum interference and "
-                    "depth for recoloring reached");
+                    "depth for recoloring reached. Use "
+                    "-fexhaustive-register-search to skip cutoffs");
   }
   return Reg;
 }
@@ -2299,9 +2317,14 @@ bool RAGreedy::runOnMachineFunction(MachineFunction &mf) {
                << "********** Function: " << mf.getName() << '\n');
 
   MF = &mf;
-  TRI = MF->getTarget().getRegisterInfo();
-  TII = MF->getTarget().getInstrInfo();
+  const TargetMachine &TM = MF->getTarget();
+  TRI = TM.getSubtargetImpl()->getRegisterInfo();
+  TII = TM.getSubtargetImpl()->getInstrInfo();
   RCI.runOnMachineFunction(mf);
+
+  EnableLocalReassign = EnableLocalReassignment ||
+    TM.getSubtargetImpl()->enableRALocalReassignment(TM.getOptLevel());
+
   if (VerifyEnabled)
     MF->verify(this, "Before greedy register allocator");