[llvm-commits] [llvm] r126975 - in /llvm/trunk/lib/CodeGen: RegAllocGreedy.cpp SpillPlacement.cpp SpillPlacement.h

[Jakob Stoklund Olesen]

Author: stoklund
Date: Thu Mar  3 18:58:40 2011
New Revision: 126975

URL: http://llvm.org/viewvc/llvm-project?rev=126975&view=rev
Log:
Precompute block frequencies, pow() isn't free.

Modified:
    llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp
    llvm/trunk/lib/CodeGen/SpillPlacement.cpp
    llvm/trunk/lib/CodeGen/SpillPlacement.h

Modified: llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp?rev=126975&r1=126974&r2=126975&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp Thu Mar  3 18:58:40 2011
@@ -602,7 +602,7 @@
     // The local cost of spill code in this block is the block frequency times
     // the number of spill instructions inserted.
     if (Inserts)
-      LocalCost += Inserts * SpillPlacer->getBlockFrequency(BI.MBB);
+      LocalCost += Inserts * SpillPlacer->getBlockFrequency(BC.Number);
   }
   DEBUG(dbgs() << "Local cost of " << PrintReg(PhysReg, TRI) << " = "
                << LocalCost << '\n');
@@ -625,8 +625,7 @@
     Inserts += LiveBundles[Bundles->getBundle(BC.Number, 1)] !=
                  (BC.Exit == SpillPlacement::PrefReg);
     if (Inserts)
-      GlobalCost +=
-        Inserts * SpillPlacer->getBlockFrequency(SA->LiveBlocks[i].MBB);
+      GlobalCost += Inserts * SpillPlacer->getBlockFrequency(BC.Number);
   }
   DEBUG(dbgs() << "Global cost = " << GlobalCost << '\n');
   return GlobalCost;
@@ -1089,7 +1088,7 @@
   unsigned BestAfter = 0;
   float BestDiff = 0;
 
-  const float blockFreq = SpillPlacer->getBlockFrequency(BI.MBB);
+  const float blockFreq = SpillPlacer->getBlockFrequency(BI.MBB->getNumber());
   SmallVector<float, 8> GapWeight;
 
   Order.rewind();

Modified: llvm/trunk/lib/CodeGen/SpillPlacement.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SpillPlacement.cpp?rev=126975&r1=126974&r2=126975&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SpillPlacement.cpp (original)
+++ llvm/trunk/lib/CodeGen/SpillPlacement.cpp Thu Mar  3 18:58:40 2011
@@ -175,9 +175,12 @@
   nodes = new Node[bundles->getNumBundles()];
 
   // Compute total ingoing and outgoing block frequencies for all bundles.
+  BlockFrequency.resize(mf.getNumBlockIDs());
   for (MachineFunction::iterator I = mf.begin(), E = mf.end(); I != E; ++I) {
-    float Freq = getBlockFrequency(I);
+    float Freq = LiveIntervals::getSpillWeight(true, false,
+                                               loops->getLoopDepth(I));
     unsigned Num = I->getNumber();
+    BlockFrequency[Num] = Freq;
     nodes[bundles->getBundle(Num, 1)].Frequency[0] += Freq;
     nodes[bundles->getBundle(Num, 0)].Frequency[1] += Freq;
   }
@@ -206,8 +209,7 @@
 prepareNodes(const SmallVectorImpl<BlockConstraint> &LiveBlocks) {
   for (SmallVectorImpl<BlockConstraint>::const_iterator I = LiveBlocks.begin(),
        E = LiveBlocks.end(); I != E; ++I) {
-    MachineBasicBlock *MBB = MF->getBlockNumbered(I->Number);
-    float Freq = getBlockFrequency(MBB);
+    float Freq = getBlockFrequency(I->Number);
 
     // Is this a transparent block? Link ingoing and outgoing bundles.
     if (I->Entry == DontCare && I->Exit == DontCare) {
@@ -320,11 +322,3 @@
     }
   return Perfect;
 }
-
-/// getBlockFrequency - Return our best estimate of the block frequency which is
-/// the expected number of block executions per function invocation.
-float SpillPlacement::getBlockFrequency(const MachineBasicBlock *MBB) {
-  // Use the unnormalized spill weight for real block frequencies.
-  return LiveIntervals::getSpillWeight(true, false, loops->getLoopDepth(MBB));
-}
-

Modified: llvm/trunk/lib/CodeGen/SpillPlacement.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SpillPlacement.h?rev=126975&r1=126974&r2=126975&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SpillPlacement.h (original)
+++ llvm/trunk/lib/CodeGen/SpillPlacement.h Thu Mar  3 18:58:40 2011
@@ -27,6 +27,7 @@
 #ifndef LLVM_CODEGEN_SPILLPLACEMENT_H
 #define LLVM_CODEGEN_SPILLPLACEMENT_H
 
+#include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 
 namespace llvm {
@@ -35,7 +36,6 @@
 class EdgeBundles;
 class MachineBasicBlock;
 class MachineLoopInfo;
-template <typename> class SmallVectorImpl;
 
 class SpillPlacement  : public MachineFunctionPass {
   struct Node;
@@ -48,6 +48,9 @@
   // caller.
   BitVector *ActiveNodes;
 
+  // Block frequencies are computed once. Indexed by block number.
+  SmallVector<float, 4> BlockFrequency;
+
 public:
   static char ID; // Pass identification, replacement for typeid.
 
@@ -91,7 +94,9 @@
 
   /// getBlockFrequency - Return the estimated block execution frequency per
   /// function invocation.
-  float getBlockFrequency(const MachineBasicBlock*);
+  float getBlockFrequency(unsigned Number) const {
+    return BlockFrequency[Number];
+  }
 
 private:
   virtual bool runOnMachineFunction(MachineFunction&);