X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FExecutionDepsFix.cpp;h=2311842671a1515378b94657fe250c68dbd623b5;hb=10ad98bbbb00d67d4272e8f29186a65e2a75215e;hp=d094411116d4ca432a2c9fec5de4b164508cf486;hpb=2947f730a96fc602ea008bba1929ae4f0638850a;p=oota-llvm.git

diff --git a/lib/CodeGen/ExecutionDepsFix.cpp b/lib/CodeGen/ExecutionDepsFix.cpp
index d094411116d..2311842671a 100644
--- a/lib/CodeGen/ExecutionDepsFix.cpp
+++ b/lib/CodeGen/ExecutionDepsFix.cpp
@@ -59,7 +59,7 @@ struct DomainValue {
 
   // Pointer to the next DomainValue in a chain.  When two DomainValues are
   // merged, Victim.Next is set to point to Victor, so old DomainValue
-  // references can be updated by folowing the chain.
+  // references can be updated by following the chain.
   DomainValue *Next;
 
   // Twiddleable instructions using or defining these registers.
@@ -454,7 +454,7 @@ void ExeDepsFix::processDefs(MachineInstr *MI, bool Kill) {
   assert(!MI->isDebugValue() && "Won't process debug values");
   const MCInstrDesc &MCID = MI->getDesc();
   for (unsigned i = 0,
-         e = MCID.isVariadic() ? MI->getNumOperands() : MCID.getNumDefs();
+         e = MI->isVariadic() ? MI->getNumOperands() : MCID.getNumDefs();
          i != e; ++i) {
     MachineOperand &MO = MI->getOperand(i);
     if (!MO.isReg())
@@ -471,11 +471,34 @@ void ExeDepsFix::processDefs(MachineInstr *MI, bool Kill) {
     DEBUG(dbgs() << TRI->getName(RC->getRegister(rx)) << ":\t" << CurInstr
                  << '\t' << *MI);
 
+    // How many instructions since rx was last written?
+    unsigned Clearance = CurInstr - LiveRegs[rx].Def;
     LiveRegs[rx].Def = CurInstr;
 
     // Kill off domains redefined by generic instructions.
     if (Kill)
       kill(rx);
+
+    // Verify clearance before partial register updates.
+    unsigned Pref = TII->getPartialRegUpdateClearance(MI, i, TRI);
+    if (!Pref)
+      continue;
+    DEBUG(dbgs() << "Clearance: " << Clearance << ", want " << Pref);
+    if (Pref > Clearance) {
+      DEBUG(dbgs() << ": Break dependency.\n");
+      TII->breakPartialRegDependency(MI, i, TRI);
+      continue;
+    }
+
+    // The current clearance seems OK, but we may be ignoring a def from a
+    // back-edge.
+    if (!SeenUnknownBackEdge || Pref <= unsigned(CurInstr)) {
+      DEBUG(dbgs() << ": OK.\n");
+      continue;
+    }
+
+    // A def from an unprocessed back-edge may make us break this dependency.
+    DEBUG(dbgs() << ": Wait for back-edge to resolve.\n");
   }
 
   ++CurInstr;
@@ -577,6 +600,9 @@ void ExeDepsFix::visitSoftInstr(MachineInstr *mi, unsigned mask) {
   while (!Regs.empty()) {
     if (!dv) {
       dv = Regs.pop_back_val().Value;
+      // Force the first dv to match the current instruction.
+      dv->AvailableDomains = dv->getCommonDomains(available);
+      assert(dv->AvailableDomains && "Domain should have been filtered");
       continue;
     }
 
@@ -594,14 +620,18 @@ void ExeDepsFix::visitSoftInstr(MachineInstr *mi, unsigned mask) {
   }
 
   // dv is the DomainValue we are going to use for this instruction.
-  if (!dv)
+  if (!dv) {
     dv = alloc();
-  dv->AvailableDomains = available;
+    dv->AvailableDomains = available;
+  }
   dv->Instrs.push_back(mi);
 
-  // Finally set all defs and non-collapsed uses to dv.
-  for (unsigned i = 0, e = mi->getDesc().getNumOperands(); i != e; ++i) {
-    MachineOperand &mo = mi->getOperand(i);
+  // Finally set all defs and non-collapsed uses to dv. We must iterate through
+  // all the operators, including imp-def ones.
+  for (MachineInstr::mop_iterator ii = mi->operands_begin(),
+                                  ee = mi->operands_end();
+                                  ii != ee; ++ii) {
+    MachineOperand &mo = *ii;
     if (!mo.isReg()) continue;
     int rx = regIndex(mo.getReg());
     if (rx < 0) continue;
@@ -627,7 +657,7 @@ bool ExeDepsFix::runOnMachineFunction(MachineFunction &mf) {
   bool anyregs = false;
   for (TargetRegisterClass::const_iterator I = RC->begin(), E = RC->end();
        I != E; ++I)
-    if (MF->getRegInfo().isPhysRegUsed(*I)) {
+    if (MF->getRegInfo().isPhysRegOrOverlapUsed(*I)) {
       anyregs = true;
       break;
     }
@@ -639,7 +669,8 @@ bool ExeDepsFix::runOnMachineFunction(MachineFunction &mf) {
     // or -1.
     AliasMap.resize(TRI->getNumRegs(), -1);
     for (unsigned i = 0, e = RC->getNumRegs(); i != e; ++i)
-      for (const unsigned *AI = TRI->getOverlaps(RC->getRegister(i)); *AI; ++AI)
+      for (MCRegAliasIterator AI(RC->getRegister(i), TRI, true);
+           AI.isValid(); ++AI)
         AliasMap[*AI] = i;
   }
 
@@ -663,6 +694,10 @@ bool ExeDepsFix::runOnMachineFunction(MachineFunction &mf) {
   for (unsigned i = 0, e = Loops.size(); i != e; ++i) {
     MachineBasicBlock *MBB = Loops[i];
     enterBasicBlock(MBB);
+    for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end(); I != E;
+        ++I)
+      if (!I->isDebugValue())
+        processDefs(I, false);
     leaveBasicBlock(MBB);
   }