Convert RAGreedy to LiveRegMatrix interference checking.

Stop depending on the LiveIntervalUnions in RegAllocBase, they are about
to be removed.

The changes are mostly replacing register alias iterators with regunit
iterators, and querying LiveRegMatrix instrad of RegAllocBase.

InterferenceCache is converted to work with per-regunit
LiveIntervalUnions, and it checks fixed regunit interference separately,
using the fixed live intervals provided by LiveIntervalAnalysis.

The local splitting helper calcGapWeights() is also considering fixed
regunit interference which is kept on the side now.

llvm-svn: 158867

1 files changed, 64 insertions, 29 deletions

diff --git a/llvm/lib/CodeGen/InterferenceCache.cpp b/llvm/lib/CodeGen/InterferenceCache.cpp
index 9b6d496b060..1541bf0c851 100644
--- a/llvm/lib/CodeGen/InterferenceCache.cpp
+++ b/llvm/lib/CodeGen/InterferenceCache.cpp
@@ -39,7 +39,7 @@ InterferenceCache::Entry *InterferenceCache::get(unsigned PhysReg) {
   unsigned E = PhysRegEntries[PhysReg];
   if (E < CacheEntries && Entries[E].getPhysReg() == PhysReg) {
     if (!Entries[E].valid(LIUArray, TRI))
-      Entries[E].revalidate();
+      Entries[E].revalidate(LIUArray, TRI);
     return &Entries[E];
   }
   // No valid entry exists, pick the next round-robin entry.
@@ -61,13 +61,15 @@ InterferenceCache::Entry *InterferenceCache::get(unsigned PhysReg) {
 }
 
 /// revalidate - LIU contents have changed, update tags.
-void InterferenceCache::Entry::revalidate() {
+void InterferenceCache::Entry::revalidate(LiveIntervalUnion *LIUArray,
+                                          const TargetRegisterInfo *TRI) {
   // Invalidate all block entries.
   ++Tag;
   // Invalidate all iterators.
   PrevPos = SlotIndex();
-  for (unsigned i = 0, e = Aliases.size(); i != e; ++i)
-    Aliases[i].second = Aliases[i].first->getTag();
+  unsigned i = 0;
+  for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units, ++i)
+    RegUnits[i].VirtTag = LIUArray[*Units].getTag();
 }
 
 void InterferenceCache::Entry::reset(unsigned physReg,
@@ -79,28 +81,23 @@ void InterferenceCache::Entry::reset(unsigned physReg,
   ++Tag;
   PhysReg = physReg;
   Blocks.resize(MF->getNumBlockIDs());
-  Aliases.clear();
-  for (MCRegAliasIterator AI(PhysReg, TRI, true); AI.isValid(); ++AI) {
-    LiveIntervalUnion *LIU = LIUArray + *AI;
-    Aliases.push_back(std::make_pair(LIU, LIU->getTag()));
-  }
 
   // Reset iterators.
   PrevPos = SlotIndex();
-  unsigned e = Aliases.size();
-  Iters.resize(e);
-  for (unsigned i = 0; i != e; ++i)
-    Iters[i].setMap(Aliases[i].first->getMap());
+  RegUnits.clear();
+  for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
+    RegUnits.push_back(LIUArray[*Units]);
+    RegUnits.back().Fixed = &LIS->getRegUnit(*Units);
+  }
 }
 
 bool InterferenceCache::Entry::valid(LiveIntervalUnion *LIUArray,
                                      const TargetRegisterInfo *TRI) {
-  unsigned i = 0, e = Aliases.size();
-  for (MCRegAliasIterator AI(PhysReg, TRI, true); AI.isValid(); ++AI, ++i) {
-    LiveIntervalUnion *LIU = LIUArray + *AI;
-    if (i == e ||  Aliases[i].first != LIU)
+  unsigned i = 0, e = RegUnits.size();
+  for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units, ++i) {
+    if (i == e)
       return false;
-    if (LIU->changedSince(Aliases[i].second))
+    if (LIUArray[*Units].changedSince(RegUnits[i].VirtTag))
       return false;
   }
   return i == e;
@@ -112,12 +109,20 @@ void InterferenceCache::Entry::update(unsigned MBBNum) {
 
   // Use advanceTo only when possible.
   if (PrevPos != Start) {
-    if (!PrevPos.isValid() || Start < PrevPos)
-      for (unsigned i = 0, e = Iters.size(); i != e; ++i)
-        Iters[i].find(Start);
-    else
-      for (unsigned i = 0, e = Iters.size(); i != e; ++i)
-        Iters[i].advanceTo(Start);
+    if (!PrevPos.isValid() || Start < PrevPos) {
+      for (unsigned i = 0, e = RegUnits.size(); i != e; ++i) {
+        RegUnitInfo &RUI = RegUnits[i];
+        RUI.VirtI.find(Start);
+        RUI.FixedI = RUI.Fixed->find(Start);
+      }
+    } else {
+      for (unsigned i = 0, e = RegUnits.size(); i != e; ++i) {
+        RegUnitInfo &RUI = RegUnits[i];
+        RUI.VirtI.advanceTo(Start);
+        if (RUI.FixedI != RUI.Fixed->end())
+          RUI.FixedI = RUI.Fixed->advanceTo(RUI.FixedI, Start);
+      }
+    }
     PrevPos = Start;
   }
 
@@ -129,9 +134,9 @@ void InterferenceCache::Entry::update(unsigned MBBNum) {
     BI->Tag = Tag;
     BI->First = BI->Last = SlotIndex();
 
-    // Check for first interference.
-    for (unsigned i = 0, e = Iters.size(); i != e; ++i) {
-      Iter &I = Iters[i];
+    // Check for first interference from virtregs.
+    for (unsigned i = 0, e = RegUnits.size(); i != e; ++i) {
+      LiveIntervalUnion::SegmentIter &I = RegUnits[i].VirtI;
       if (!I.valid())
         continue;
       SlotIndex StartI = I.start();
@@ -141,6 +146,19 @@ void InterferenceCache::Entry::update(unsigned MBBNum) {
         BI->First = StartI;
     }
 
+    // Same thing for fixed interference.
+    for (unsigned i = 0, e = RegUnits.size(); i != e; ++i) {
+      LiveInterval::const_iterator I = RegUnits[i].FixedI;
+      LiveInterval::const_iterator E = RegUnits[i].Fixed->end();
+      if (I == E)
+        continue;
+      SlotIndex StartI = I->start;
+      if (StartI >= Stop)
+        continue;
+      if (!BI->First.isValid() || StartI < BI->First)
+        BI->First = StartI;
+    }
+
     // Also check for register mask interference.
     RegMaskSlots = LIS->getRegMaskSlotsInBlock(MBBNum);
     RegMaskBits = LIS->getRegMaskBitsInBlock(MBBNum);
@@ -168,8 +186,8 @@ void InterferenceCache::Entry::update(unsigned MBBNum) {
   }
 
   // Check for last interference in block.
-  for (unsigned i = 0, e = Iters.size(); i != e; ++i) {
-    Iter &I = Iters[i];
+  for (unsigned i = 0, e = RegUnits.size(); i != e; ++i) {
+    LiveIntervalUnion::SegmentIter &I = RegUnits[i].VirtI;
     if (!I.valid() || I.start() >= Stop)
       continue;
     I.advanceTo(Stop);
@@ -183,6 +201,23 @@ void InterferenceCache::Entry::update(unsigned MBBNum) {
       ++I;
   }
 
+  // Fixed interference.
+  for (unsigned i = 0, e = RegUnits.size(); i != e; ++i) {
+    LiveInterval::iterator &I = RegUnits[i].FixedI;
+    LiveInterval *LI = RegUnits[i].Fixed;
+    if (I == LI->end() || I->start >= Stop)
+      continue;
+    I = LI->advanceTo(I, Stop);
+    bool Backup = I == LI->end() || I->start >= Stop;
+    if (Backup)
+      --I;
+    SlotIndex StopI = I->end;
+    if (!BI->Last.isValid() || StopI > BI->Last)
+      BI->Last = StopI;
+    if (Backup)
+      ++I;
+  }
+
   // Also check for register mask interference.
   SlotIndex Limit = BI->Last.isValid() ? BI->Last : Start;
   for (unsigned i = RegMaskSlots.size();