X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FMachineSink.cpp;h=29cfb49953b9a227573daa61b6c172d5acfc202b;hb=70303688bc489a316cb0892499ac4024088fa58a;hp=5969c0b3455d257547cdb7b30ce34fe43679e5b3;hpb=44be1a8d661cfab0cc3d11b0dd158271b2d2ca04;p=oota-llvm.git

diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp
index 5969c0b3455..29cfb49953b 100644
--- a/lib/CodeGen/MachineSink.cpp
+++ b/lib/CodeGen/MachineSink.cpp
@@ -57,7 +57,9 @@ namespace {
 
   public:
     static char ID; // Pass identification
-    MachineSinking() : MachineFunctionPass(ID) {}
+    MachineSinking() : MachineFunctionPass(ID) {
+      initializeMachineSinkingPass(*PassRegistry::getPassRegistry());
+    }
 
     virtual bool runOnMachineFunction(MachineFunction &MF);
 
@@ -94,8 +96,13 @@ namespace {
 } // end anonymous namespace
 
 char MachineSinking::ID = 0;
-INITIALIZE_PASS(MachineSinking, "machine-sink",
-                "Machine code sinking", false, false);
+INITIALIZE_PASS_BEGIN(MachineSinking, "machine-sink",
+                "Machine code sinking", false, false)
+INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
+INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
+INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_PASS_END(MachineSinking, "machine-sink",
+                "Machine code sinking", false, false)
 
 FunctionPass *llvm::createMachineSinkingPass() { return new MachineSinking(); }
 
@@ -258,8 +265,11 @@ bool MachineSinking::ProcessBlock(MachineBasicBlock &MBB) {
     if (MI->isDebugValue())
       continue;
 
-    if (PerformTrivialForwardCoalescing(MI, &MBB))
+    bool Joined = PerformTrivialForwardCoalescing(MI, &MBB);
+    if (Joined) {
+      MadeChange = true;
       continue;
+    }
 
     if (SinkInstruction(MI, SawStore))
       ++NumSunk, MadeChange = true;
@@ -281,7 +291,7 @@ bool MachineSinking::isWorthBreakingCriticalEdge(MachineInstr *MI,
   if (!CEBCandidates.insert(std::make_pair(From, To)))
     return true;
 
-  if (!(MI->isCopyLike() || MI->getDesc().isAsCheapAsAMove()))
+  if (!MI->isCopy() && !MI->getDesc().isAsCheapAsAMove())
     return true;
 
   // MI is cheap, we probably don't want to break the critical edge for it.
@@ -368,9 +378,37 @@ MachineBasicBlock *MachineSinking::SplitCriticalEdge(MachineInstr *MI,
   return FromBB->SplitCriticalEdge(ToBB, this);
 }
 
+static bool AvoidsSinking(MachineInstr *MI, MachineRegisterInfo *MRI) {
+  return MI->isInsertSubreg() || MI->isSubregToReg() || MI->isRegSequence();
+}
+
+/// collectDebgValues - Scan instructions following MI and collect any 
+/// matching DBG_VALUEs.
+static void collectDebugValues(MachineInstr *MI, 
+                               SmallVector<MachineInstr *, 2> & DbgValues) {
+  DbgValues.clear();
+  if (!MI->getOperand(0).isReg())
+    return;
+
+  MachineBasicBlock::iterator DI = MI; ++DI;
+  for (MachineBasicBlock::iterator DE = MI->getParent()->end();
+       DI != DE; ++DI) {
+    if (!DI->isDebugValue())
+      return;
+    if (DI->getOperand(0).isReg() &&
+        DI->getOperand(0).getReg() == MI->getOperand(0).getReg())
+      DbgValues.push_back(DI);
+  }
+}
+
 /// SinkInstruction - Determine whether it is safe to sink the specified machine
 /// instruction out of its current block into a successor.
 bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) {
+  // Don't sink insert_subreg, subreg_to_reg, reg_sequence. These are meant to
+  // be close to the source to make it easier to coalesce.
+  if (AvoidsSinking(MI, MRI))
+    return false;
+
   // Check if it's safe to move the instruction.
   if (!MI->isSafeToMove(TII, AA, SawStore))
     return false;
@@ -579,10 +617,22 @@ bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) {
   while (InsertPos != SuccToSinkTo->end() && InsertPos->isPHI())
     ++InsertPos;
 
+  // collect matching debug values.
+  SmallVector<MachineInstr *, 2> DbgValuesToSink;
+  collectDebugValues(MI, DbgValuesToSink);
+
   // Move the instruction.
   SuccToSinkTo->splice(InsertPos, ParentBlock, MI,
                        ++MachineBasicBlock::iterator(MI));
 
+  // Move debug values.
+  for (SmallVector<MachineInstr *, 2>::iterator DBI = DbgValuesToSink.begin(),
+         DBE = DbgValuesToSink.end(); DBI != DBE; ++DBI) {
+    MachineInstr *DbgMI = *DBI;
+    SuccToSinkTo->splice(InsertPos, ParentBlock,  DbgMI,
+                         ++MachineBasicBlock::iterator(DbgMI));
+  }
+
   // Conservatively, clear any kill flags, since it's possible that they are no
   // longer correct.
   MI->clearKillInfo();