Support standard DWARF TLS opcode; Darwin and PS4 use it.

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

diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index c03773f80370bb8f6261c98926bba48764764ca7..cc08045c7b898825b8d80aa1e2017f368b8129ed 100644 (file)
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -67,6 +67,13 @@ static cl::opt<bool> EnableSubRegLiveness(
   "enable-subreg-liveness", cl::Hidden, cl::init(true),
   cl::desc("Enable subregister liveness tracking."));
 
+namespace llvm {
+cl::opt<bool> UseSegmentSetForPhysRegs(
+    "use-segment-set-for-physregs", cl::Hidden, cl::init(true),
+    cl::desc(
+        "Use segment set for the computation of the live ranges of physregs."));
+}
+
 void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesCFG();
   AU.addRequired<AliasAnalysis>();
@@ -268,6 +275,10 @@ void LiveIntervals::computeRegUnitRange(LiveRange &LR, unsigned Unit) {
         LRCalc->extendToUses(LR, Reg);
     }
   }
+
+  // Flush the segment set to the segment vector.
+  if (UseSegmentSetForPhysRegs)
+    LR.flushSegmentSet();
 }
 
 
@@ -300,7 +311,8 @@ void LiveIntervals::computeLiveInRegUnits() {
         unsigned Unit = *Units;
         LiveRange *LR = RegUnitRanges[Unit];
         if (!LR) {
-          LR = RegUnitRanges[Unit] = new LiveRange();
+          // Use segment set to speed-up initial computation of the live range.
+          LR = RegUnitRanges[Unit] = new LiveRange(UseSegmentSetForPhysRegs);
           NewRanges.push_back(Unit);
         }
         VNInfo *VNI = LR->createDeadDef(Begin, getVNInfoAllocator());
@@ -448,23 +460,34 @@ bool LiveIntervals::computeDeadValues(LiveInterval &LI,
   for (auto VNI : LI.valnos) {
     if (VNI->isUnused())
       continue;
-    LiveRange::iterator I = LI.FindSegmentContaining(VNI->def);
+    SlotIndex Def = VNI->def;
+    LiveRange::iterator I = LI.FindSegmentContaining(Def);
     assert(I != LI.end() && "Missing segment for VNI");
-    if (I->end != VNI->def.getDeadSlot())
+
+    // Is the register live before? Otherwise we may have to add a read-undef
+    // flag for subregister defs.
+    if (MRI->tracksSubRegLiveness()) {
+      if ((I == LI.begin() || std::prev(I)->end < Def) && !VNI->isPHIDef()) {
+        MachineInstr *MI = getInstructionFromIndex(Def);
+        MI->addRegisterDefReadUndef(LI.reg);
+      }
+    }
+
+    if (I->end != Def.getDeadSlot())
       continue;
     if (VNI->isPHIDef()) {
       // This is a dead PHI. Remove it.
       VNI->markUnused();
       LI.removeSegment(I);
-      DEBUG(dbgs() << "Dead PHI at " << VNI->def << " may separate interval\n");
+      DEBUG(dbgs() << "Dead PHI at " << Def << " may separate interval\n");
       PHIRemoved = true;
     } else {
       // This is a dead def. Make sure the instruction knows.
-      MachineInstr *MI = getInstructionFromIndex(VNI->def);
+      MachineInstr *MI = getInstructionFromIndex(Def);
       assert(MI && "No instruction defining live value");
       MI->addRegisterDead(LI.reg, TRI);
       if (dead && MI->allDefsAreDead()) {
-        DEBUG(dbgs() << "All defs dead: " << VNI->def << '\t' << *MI);
+        DEBUG(dbgs() << "All defs dead: " << Def << '\t' << *MI);
         dead->push_back(MI);
       }
     }