[llvm-commits] [llvm] r129187 - in /llvm/trunk/lib/CodeGen: InterferenceCache.cpp InterferenceCache.h

[Jakob Stoklund Olesen]

Author: stoklund
Date: Fri Apr  8 21:59:05 2011
New Revision: 129187

URL: http://llvm.org/viewvc/llvm-project?rev=129187&view=rev
Log:
Precompute interference for neighbor blocks as long as there is no interference.

This doesn't require seeking in the live interval union, so it is very cheap.

Modified:
    llvm/trunk/lib/CodeGen/InterferenceCache.cpp
    llvm/trunk/lib/CodeGen/InterferenceCache.h

Modified: llvm/trunk/lib/CodeGen/InterferenceCache.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/InterferenceCache.cpp?rev=129187&r1=129186&r2=129187&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/InterferenceCache.cpp (original)
+++ llvm/trunk/lib/CodeGen/InterferenceCache.cpp Fri Apr  8 21:59:05 2011
@@ -26,7 +26,7 @@
   TRI = tri;
   PhysRegEntries.assign(TRI->getNumRegs(), 0);
   for (unsigned i = 0; i != CacheEntries; ++i)
-    Entries[i].clear(indexes);
+    Entries[i].clear(mf, indexes);
 }
 
 InterferenceCache::Entry *InterferenceCache::get(unsigned PhysReg) {
@@ -91,10 +91,6 @@
 }
 
 void InterferenceCache::Entry::update(unsigned MBBNum) {
-  BlockInterference *BI = &Blocks[MBBNum];
-  BI->Tag = Tag;
-  BI->First = BI->Last = SlotIndex();
-
   SlotIndex Start, Stop;
   tie(Start, Stop) = Indexes->getMBBRange(MBBNum);
 
@@ -109,23 +105,39 @@
     PrevPos = Start;
   }
 
-  // Check for first interference.
-  for (unsigned i = 0, e = Iters.size(); i != e; ++i) {
-    Iter &I = Iters[i];
-    if (!I.valid())
-      continue;
-    SlotIndex StartI = I.start();
-    if (StartI >= Stop)
-      continue;
-    if (!BI->First.isValid() || StartI < BI->First)
-      BI->First = StartI;
+  MachineFunction::const_iterator MFI = MF->getBlockNumbered(MBBNum);
+  BlockInterference *BI = &Blocks[MBBNum];
+  for (;;) {
+    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];
+      if (!I.valid())
+        continue;
+      SlotIndex StartI = I.start();
+      if (StartI >= Stop)
+        continue;
+      if (!BI->First.isValid() || StartI < BI->First)
+        BI->First = StartI;
+    }
+
+    PrevPos = Stop;
+    if (BI->First.isValid())
+      break;
+
+    // No interference in this block? Go ahead and precompute the next block.
+    if (++MFI == MF->end())
+      return;
+    MBBNum = MFI->getNumber();
+    BI = &Blocks[MBBNum];
+    if (BI->Tag == Tag)
+      return;
+    tie(Start, Stop) = Indexes->getMBBRange(MBBNum);
   }
 
-  // No interference in block.
-  if (!BI->First.isValid())
-    return;
-
-  // Check for last interference.
+  // Check for last interference in block.
   for (unsigned i = 0, e = Iters.size(); i != e; ++i) {
     Iter &I = Iters[i];
     if (!I.valid() || I.start() >= Stop)
@@ -140,5 +152,4 @@
     if (Backup)
       ++I;
   }
-  PrevPos = Stop;
 }

Modified: llvm/trunk/lib/CodeGen/InterferenceCache.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/InterferenceCache.h?rev=129187&r1=129186&r2=129187&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/InterferenceCache.h (original)
+++ llvm/trunk/lib/CodeGen/InterferenceCache.h Fri Apr  8 21:59:05 2011
@@ -43,6 +43,9 @@
     /// change.
     unsigned Tag;
 
+    /// MF - The current function.
+    MachineFunction *MF;
+
     /// Indexes - Mapping block numbers to SlotIndex ranges.
     SlotIndexes *Indexes;
 
@@ -67,8 +70,9 @@
   public:
     Entry() : PhysReg(0), Tag(0), Indexes(0) {}
 
-    void clear(SlotIndexes *indexes) {
+    void clear(MachineFunction *mf, SlotIndexes *indexes) {
       PhysReg = 0;
+      MF = mf;
       Indexes = indexes;
     }