mi-sched: Don't call MBB.size() in initSUnits. The driver already has instr count.

This fixes a pathological compile time problem with very large blocks
and lots of scheduling boundaries.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189116 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 30 insertions, 16 deletions

diff --git a/lib/CodeGen/DFAPacketizer.cpp b/lib/CodeGen/DFAPacketizer.cpp
index 840a10128d..6619bcfd19 100644
--- a/lib/CodeGen/DFAPacketizer.cpp
+++ b/lib/CodeGen/DFAPacketizer.cpp
@@ -160,7 +160,8 @@ void VLIWPacketizerList::PacketizeMIs(MachineBasicBlock *MBB,
                                       MachineBasicBlock::iterator EndItr) {
   assert(VLIWScheduler && "VLIW Scheduler is not initialized!");
   VLIWScheduler->startBlock(MBB);
-  VLIWScheduler->enterRegion(MBB, BeginItr, EndItr, MBB->size());
+  VLIWScheduler->enterRegion(MBB, BeginItr, EndItr,
+                             std::distance(BeginItr, EndItr));
   VLIWScheduler->schedule();
 
   // Generate MI -> SU map.
diff --git a/lib/CodeGen/MachineScheduler.cpp b/lib/CodeGen/MachineScheduler.cpp
index a6c5a9f933..da6920575d 100644
--- a/lib/CodeGen/MachineScheduler.cpp
+++ b/lib/CodeGen/MachineScheduler.cpp
@@ -255,14 +255,15 @@ bool MachineScheduler::runOnMachineFunction(MachineFunction &mf) {
 
       // The next region starts above the previous region. Look backward in the
       // instruction stream until we find the nearest boundary.
+      unsigned NumRegionInstrs = 0;
       MachineBasicBlock::iterator I = RegionEnd;
-      for(;I != MBB->begin(); --I, --RemainingInstrs) {
+      for(;I != MBB->begin(); --I, --RemainingInstrs, ++NumRegionInstrs) {
         if (TII->isSchedulingBoundary(llvm::prior(I), MBB, *MF))
           break;
       }
       // Notify the scheduler of the region, even if we may skip scheduling
       // it. Perhaps it still needs to be bundled.
-      Scheduler->enterRegion(MBB, I, RegionEnd, RemainingInstrs);
+      Scheduler->enterRegion(MBB, I, RegionEnd, NumRegionInstrs);
 
       // Skip empty scheduling regions (0 or 1 schedulable instructions).
       if (I == RegionEnd || I == llvm::prior(RegionEnd)) {
@@ -277,7 +278,8 @@ bool MachineScheduler::runOnMachineFunction(MachineFunction &mf) {
             << "\n  From: " << *I << "    To: ";
             if (RegionEnd != MBB->end()) dbgs() << *RegionEnd;
             else dbgs() << "End";
-            dbgs() << " Remaining: " << RemainingInstrs << "\n");
+            dbgs() << " RegionInstrs: " << NumRegionInstrs
+            << " Remaining: " << RemainingInstrs << "\n");
 
       // Schedule a region: possibly reorder instructions.
       // This invalidates 'RegionEnd' and 'I'.
@@ -446,9 +448,9 @@ bool ScheduleDAGMI::checkSchedLimit() {
 void ScheduleDAGMI::enterRegion(MachineBasicBlock *bb,
                                 MachineBasicBlock::iterator begin,
                                 MachineBasicBlock::iterator end,
-                                unsigned endcount)
+                                unsigned regioninstrs)
 {
-  ScheduleDAGInstrs::enterRegion(bb, begin, end, endcount);
+  ScheduleDAGInstrs::enterRegion(bb, begin, end, regioninstrs);
 
   // For convenience remember the end of the liveness region.
   LiveRegionEnd =
diff --git a/lib/CodeGen/PostRASchedulerList.cpp b/lib/CodeGen/PostRASchedulerList.cpp
index 27f56762de..b8747b9330 100644
--- a/lib/CodeGen/PostRASchedulerList.cpp
+++ b/lib/CodeGen/PostRASchedulerList.cpp
@@ -127,6 +127,12 @@ namespace {
     /// The schedule. Null SUnit*'s represent noop instructions.
     std::vector<SUnit*> Sequence;
 
+    /// The index in BB of RegionEnd.
+    ///
+    /// This is the instruction number from the top of the current block, not
+    /// the SlotIndex. It is only used by the AntiDepBreaker.
+    unsigned EndIndex;
+
   public:
     SchedulePostRATDList(
       MachineFunction &MF, MachineLoopInfo &MLI, MachineDominatorTree &MDT,
@@ -141,11 +147,14 @@ namespace {
     ///
     void startBlock(MachineBasicBlock *BB);
 
+    // Set the index of RegionEnd within the current BB.
+    void setEndIndex(unsigned EndIdx) { EndIndex = EndIdx; }
+
     /// Initialize the scheduler state for the next scheduling region.
     virtual void enterRegion(MachineBasicBlock *bb,
                              MachineBasicBlock::iterator begin,
                              MachineBasicBlock::iterator end,
-                             unsigned endcount);
+                             unsigned regioninstrs);
 
     /// Notify that the scheduler has finished scheduling the current region.
     virtual void exitRegion();
@@ -197,7 +206,7 @@ SchedulePostRATDList::SchedulePostRATDList(
   TargetSubtargetInfo::AntiDepBreakMode AntiDepMode,
   SmallVectorImpl<const TargetRegisterClass*> &CriticalPathRCs)
   : ScheduleDAGInstrs(MF, MLI, MDT, /*IsPostRA=*/true), AA(AA),
-    LiveRegs(TRI->getNumRegs())
+    LiveRegs(TRI->getNumRegs()), EndIndex(0)
 {
   const TargetMachine &TM = MF.getTarget();
   const InstrItineraryData *InstrItins = TM.getInstrItineraryData();
@@ -223,8 +232,8 @@ SchedulePostRATDList::~SchedulePostRATDList() {
 void SchedulePostRATDList::enterRegion(MachineBasicBlock *bb,
                  MachineBasicBlock::iterator begin,
                  MachineBasicBlock::iterator end,
-                 unsigned endcount) {
-  ScheduleDAGInstrs::enterRegion(bb, begin, end, endcount);
+                 unsigned regioninstrs) {
+  ScheduleDAGInstrs::enterRegion(bb, begin, end, regioninstrs);
   Sequence.clear();
 }
 
@@ -312,20 +321,21 @@ bool PostRAScheduler::runOnMachineFunction(MachineFunction &Fn) {
     unsigned Count = MBB->size(), CurrentCount = Count;
     for (MachineBasicBlock::iterator I = Current; I != MBB->begin(); ) {
       MachineInstr *MI = llvm::prior(I);
+      --Count;
       // Calls are not scheduling boundaries before register allocation, but
       // post-ra we don't gain anything by scheduling across calls since we
       // don't need to worry about register pressure.
       if (MI->isCall() || TII->isSchedulingBoundary(MI, MBB, Fn)) {
-        Scheduler.enterRegion(MBB, I, Current, CurrentCount);
+        Scheduler.enterRegion(MBB, I, Current, CurrentCount - Count);
+        Scheduler.setEndIndex(CurrentCount);
         Scheduler.schedule();
         Scheduler.exitRegion();
         Scheduler.EmitSchedule();
         Current = MI;
-        CurrentCount = Count - 1;
+        CurrentCount = Count;
         Scheduler.Observe(MI, CurrentCount);
       }
       I = MI;
-      --Count;
       if (MI->isBundle())
         Count -= MI->getBundleSize();
     }
@@ -333,6 +343,7 @@ bool PostRAScheduler::runOnMachineFunction(MachineFunction &Fn) {
     assert((MBB->begin() == Current || CurrentCount != 0) &&
            "Instruction count mismatch!");
     Scheduler.enterRegion(MBB, MBB->begin(), Current, CurrentCount);
+    Scheduler.setEndIndex(CurrentCount);
     Scheduler.schedule();
     Scheduler.exitRegion();
     Scheduler.EmitSchedule();
diff --git a/lib/CodeGen/ScheduleDAGInstrs.cpp b/lib/CodeGen/ScheduleDAGInstrs.cpp
index 892903c238..b0245d5c3c 100644
--- a/lib/CodeGen/ScheduleDAGInstrs.cpp
+++ b/lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -178,11 +178,11 @@ void ScheduleDAGInstrs::finishBlock() {
 void ScheduleDAGInstrs::enterRegion(MachineBasicBlock *bb,
                                     MachineBasicBlock::iterator begin,
                                     MachineBasicBlock::iterator end,
-                                    unsigned endcount) {
+                                    unsigned regioninstrs) {
   assert(bb == BB && "startBlock should set BB");
   RegionBegin = begin;
   RegionEnd = end;
-  EndIndex = endcount;
+  NumRegionInstrs = regioninstrs;
   MISUnitMap.clear();
 
   ScheduleDAG::clearDAG();
@@ -664,7 +664,7 @@ void addChainDependency (AliasAnalysis *AA, const MachineFrameInfo *MFI,
 void ScheduleDAGInstrs::initSUnits() {
   // We'll be allocating one SUnit for each real instruction in the region,
   // which is contained within a basic block.
-  SUnits.reserve(BB->size());
+  SUnits.reserve(NumRegionInstrs);
 
   for (MachineBasicBlock::iterator I = RegionBegin; I != RegionEnd; ++I) {
     MachineInstr *MI = I;