[NFC][regalloc] Make VirtRegAuxInfo part of allocator state

All the state of VRAI is allocator-wide, so we can avoid creating it
every time we need it. In addition, the normalization function is
allocator-specific. In a next change, we can simplify that design in
favor of just having it as a virtual member.

Differential Revision: https://reviews.llvm.org/D88499

Author: mtrofin

llvm/include/llvm/CodeGen/CalcSpillWeights.h

@@ -91,17 +91,11 @@ class VirtRegMap;
     /// \return The spill weight. Returns negative weight for unspillable li.
     float weightCalcHelper(LiveInterval &li, SlotIndex *start = nullptr,
                            SlotIndex *end = nullptr);
-  };
-
-  /// Compute spill weights and allocation hints for all virtual register
-  /// live intervals.
-  void calculateSpillWeightsAndHints(LiveIntervals &LIS, MachineFunction &MF,
-                                     VirtRegMap *VRM,
-                                     const MachineLoopInfo &MLI,
-                                     const MachineBlockFrequencyInfo &MBFI,
-                                     VirtRegAuxInfo::NormalizingFn norm =
-                                         normalizeSpillWeight);
 
+    /// Compute spill weights and allocation hints for all virtual register
+    /// live intervals.
+    void calculateSpillWeightsAndHints();
+  };
 } // end namespace llvm
 
 #endif // LLVM_CODEGEN_CALCSPILLWEIGHTS_H

llvm/lib/CodeGen/CalcSpillWeights.cpp

@@ -28,22 +28,16 @@ using namespace llvm;
 
 #define DEBUG_TYPE "calcspillweights"
 
-void llvm::calculateSpillWeightsAndHints(LiveIntervals &LIS,
-                           MachineFunction &MF,
-                           VirtRegMap *VRM,
-                           const MachineLoopInfo &MLI,
-                           const MachineBlockFrequencyInfo &MBFI,
-                           VirtRegAuxInfo::NormalizingFn norm) {
+void VirtRegAuxInfo::calculateSpillWeightsAndHints() {
   LLVM_DEBUG(dbgs() << "********** Compute Spill Weights **********\n"
                     << "********** Function: " << MF.getName() << '\n');
 
   MachineRegisterInfo &MRI = MF.getRegInfo();
-  VirtRegAuxInfo VRAI(MF, LIS, VRM, MLI, MBFI, norm);
-  for (unsigned i = 0, e = MRI.getNumVirtRegs(); i != e; ++i) {
-    unsigned Reg = Register::index2VirtReg(i);
+  for (unsigned I = 0, E = MRI.getNumVirtRegs(); I != E; ++I) {
+    unsigned Reg = Register::index2VirtReg(I);
     if (MRI.reg_nodbg_empty(Reg))
       continue;
-    VRAI.calculateSpillWeightAndHint(LIS.getInterval(Reg));
+    calculateSpillWeightAndHint(LIS.getInterval(Reg));
   }
 }
 

llvm/lib/CodeGen/RegAllocBasic.cpp

@@ -311,10 +311,9 @@ bool RABasic::runOnMachineFunction(MachineFunction &mf) {
   RegAllocBase::init(getAnalysis<VirtRegMap>(),
                      getAnalysis<LiveIntervals>(),
                      getAnalysis<LiveRegMatrix>());
-
-  calculateSpillWeightsAndHints(*LIS, *MF, VRM,
-                                getAnalysis<MachineLoopInfo>(),
-                                getAnalysis<MachineBlockFrequencyInfo>());
+  VirtRegAuxInfo VRAI(*MF, *LIS, VRM, getAnalysis<MachineLoopInfo>(),
+                      getAnalysis<MachineBlockFrequencyInfo>());
+  VRAI.calculateSpillWeightsAndHints();
 
   SpillerInstance.reset(createInlineSpiller(*this, *MF, *VRM));
 

llvm/lib/CodeGen/RegAllocGreedy.cpp

@@ -172,6 +172,7 @@ class RAGreedy : public MachineFunctionPass,
   std::unique_ptr<Spiller> SpillerInstance;
   PQueue Queue;
   unsigned NextCascade;
+  std::unique_ptr<VirtRegAuxInfo> VRAI;
 
   // Live ranges pass through a number of stages as we try to allocate them.
   // Some of the stages may also create new live ranges:
@@ -1507,10 +1508,9 @@ bool RAGreedy::splitCanCauseEvictionChain(unsigned Evictee,
   // Now, check to see if the local interval we will create is going to be
   // expensive enough to evict somebody If so, this may cause a bad eviction
   // chain.
-  VirtRegAuxInfo VRAI(*MF, *LIS, VRM, getAnalysis<MachineLoopInfo>(), *MBFI);
   float splitArtifactWeight =
-      VRAI.futureWeight(LIS->getInterval(Evictee),
-                        Cand.Intf.first().getPrevIndex(), Cand.Intf.last());
+      VRAI->futureWeight(LIS->getInterval(Evictee),
+                         Cand.Intf.first().getPrevIndex(), Cand.Intf.last());
   if (splitArtifactWeight >= 0 && splitArtifactWeight < MaxWeight)
     return false;
 
@@ -1550,10 +1550,9 @@ bool RAGreedy::splitCanCauseLocalSpill(unsigned VirtRegToSplit,
 
   // Have we found an interval that can be evicted?
   if (FutureEvictedPhysReg) {
-    VirtRegAuxInfo VRAI(*MF, *LIS, VRM, getAnalysis<MachineLoopInfo>(), *MBFI);
     float splitArtifactWeight =
-        VRAI.futureWeight(LIS->getInterval(VirtRegToSplit),
-                          Cand.Intf.first().getPrevIndex(), Cand.Intf.last());
+        VRAI->futureWeight(LIS->getInterval(VirtRegToSplit),
+                           Cand.Intf.first().getPrevIndex(), Cand.Intf.last());
     // Will the weight of the local interval be higher than the cheapest evictee
     // weight? If so it will evict it and will not cause a spill.
     if (splitArtifactWeight >= 0 && splitArtifactWeight > CheapestEvictWeight)
@@ -3228,7 +3227,9 @@ bool RAGreedy::runOnMachineFunction(MachineFunction &mf) {
 
   initializeCSRCost();
 
-  calculateSpillWeightsAndHints(*LIS, mf, VRM, *Loops, *MBFI);
+  VRAI = std::make_unique<VirtRegAuxInfo>(*MF, *LIS, VRM, *Loops, *MBFI);
+
+  VRAI->calculateSpillWeightsAndHints();
 
   LLVM_DEBUG(LIS->dump());
 

llvm/lib/CodeGen/RegAllocPBQP.cpp

@@ -792,8 +792,9 @@ bool RegAllocPBQP::runOnMachineFunction(MachineFunction &MF) {
 
   VirtRegMap &VRM = getAnalysis<VirtRegMap>();
 
-  calculateSpillWeightsAndHints(LIS, MF, &VRM, getAnalysis<MachineLoopInfo>(),
-                                MBFI, normalizePBQPSpillWeight);
+  VirtRegAuxInfo VRAI(MF, LIS, &VRM, getAnalysis<MachineLoopInfo>(), MBFI,
+                      normalizePBQPSpillWeight);
+  VRAI.calculateSpillWeightsAndHints();
 
   std::unique_ptr<Spiller> VRegSpiller(createInlineSpiller(*this, MF, VRM));