1 files changed, 55 insertions, 17 deletions

diff --git a/llvm/lib/Target/Mips/MipsDelaySlotFiller.cpp b/llvm/lib/Target/Mips/MipsDelaySlotFiller.cpp
index aa07dac86828..84ff674569cd 100644
--- a/llvm/lib/Target/Mips/MipsDelaySlotFiller.cpp
+++ b/llvm/lib/Target/Mips/MipsDelaySlotFiller.cpp
@@ -91,15 +91,14 @@ enum CompactBranchPolicy {
 };
 
 static cl::opt<CompactBranchPolicy> MipsCompactBranchPolicy(
-  "mips-compact-branches",cl::Optional,
-  cl::init(CB_Optimal),
-  cl::desc("MIPS Specific: Compact branch policy."),
-  cl::values(
-    clEnumValN(CB_Never, "never", "Do not use compact branches if possible."),
-    clEnumValN(CB_Optimal, "optimal", "Use compact branches where appropiate (default)."),
-    clEnumValN(CB_Always, "always", "Always use compact branches if possible.")
-  )
-);
+    "mips-compact-branches", cl::Optional, cl::init(CB_Optimal),
+    cl::desc("MIPS Specific: Compact branch policy."),
+    cl::values(clEnumValN(CB_Never, "never",
+                          "Do not use compact branches if possible."),
+               clEnumValN(CB_Optimal, "optimal",
+                          "Use compact branches where appropiate (default)."),
+               clEnumValN(CB_Always, "always",
+                          "Always use compact branches if possible.")));
 
 namespace {
 
@@ -417,8 +416,14 @@ bool RegDefsUses::update(const MachineInstr &MI, unsigned Begin, unsigned End) {
   for (unsigned I = Begin; I != End; ++I) {
     const MachineOperand &MO = MI.getOperand(I);
 
-    if (MO.isReg() && MO.getReg())
-      HasHazard |= checkRegDefsUses(NewDefs, NewUses, MO.getReg(), MO.isDef());
+    if (MO.isReg() && MO.getReg()) {
+      if (checkRegDefsUses(NewDefs, NewUses, MO.getReg(), MO.isDef())) {
+        LLVM_DEBUG(dbgs() << DEBUG_TYPE ": found register hazard for operand "
+                          << I << ": ";
+                   MO.dump());
+        HasHazard = true;
+      }
+    }
   }
 
   Defs |= NewDefs;
@@ -613,12 +618,18 @@ bool MipsDelaySlotFiller::runOnMachineBasicBlock(MachineBasicBlock &MBB) {
       if (MipsCompactBranchPolicy.getValue() != CB_Always ||
            !TII->getEquivalentCompactForm(I)) {
         if (searchBackward(MBB, *I)) {
+          LLVM_DEBUG(dbgs() << DEBUG_TYPE ": found instruction for delay slot"
+                                          " in backwards search.\n");
           Filled = true;
         } else if (I->isTerminator()) {
           if (searchSuccBBs(MBB, I)) {
             Filled = true;
+            LLVM_DEBUG(dbgs() << DEBUG_TYPE ": found instruction for delay slot"
+                                            " in successor BB search.\n");
           }
         } else if (searchForward(MBB, I)) {
+          LLVM_DEBUG(dbgs() << DEBUG_TYPE ": found instruction for delay slot"
+                                          " in forwards search.\n");
           Filled = true;
         }
       }
@@ -663,6 +674,8 @@ bool MipsDelaySlotFiller::runOnMachineBasicBlock(MachineBasicBlock &MBB) {
     }
 
     // Bundle the NOP to the instruction with the delay slot.
+    LLVM_DEBUG(dbgs() << DEBUG_TYPE << ": could not fill delay slot for ";
+               I->dump());
     BuildMI(MBB, std::next(I), I->getDebugLoc(), TII->get(Mips::NOP));
     MIBundleBuilder(MBB, I, std::next(I, 2));
     ++FilledSlots;
@@ -680,13 +693,27 @@ bool MipsDelaySlotFiller::searchRange(MachineBasicBlock &MBB, IterTy Begin,
   for (IterTy I = Begin; I != End;) {
     IterTy CurrI = I;
     ++I;
-
+    LLVM_DEBUG(dbgs() << DEBUG_TYPE ": checking instruction: "; CurrI->dump());
     // skip debug value
-    if (CurrI->isDebugInstr())
+    if (CurrI->isDebugInstr()) {
+      LLVM_DEBUG(dbgs() << DEBUG_TYPE ": ignoring debug instruction: ";
+                 CurrI->dump());
       continue;
+    }
+
+    if (CurrI->isBundle()) {
+      LLVM_DEBUG(dbgs() << DEBUG_TYPE ": ignoring BUNDLE instruction: ";
+                 CurrI->dump());
+      // However, we still need to update the register def-use information.
+      RegDU.update(*CurrI, 0, CurrI->getNumOperands());
+      continue;
+    }
 
-    if (terminateSearch(*CurrI))
+    if (terminateSearch(*CurrI)) {
+      LLVM_DEBUG(dbgs() << DEBUG_TYPE ": should terminate search: ";
+                 CurrI->dump());
       break;
+    }
 
     assert((!CurrI->isCall() && !CurrI->isReturn() && !CurrI->isBranch()) &&
            "Cannot put calls, returns or branches in delay slot.");
@@ -732,6 +759,9 @@ bool MipsDelaySlotFiller::searchRange(MachineBasicBlock &MBB, IterTy Begin,
        continue;
 
     Filler = CurrI;
+    LLVM_DEBUG(dbgs() << DEBUG_TYPE ": found instruction for delay slot: ";
+               CurrI->dump());
+
     return true;
   }
 
@@ -752,8 +782,11 @@ bool MipsDelaySlotFiller::searchBackward(MachineBasicBlock &MBB,
 
   MachineBasicBlock::iterator SlotI = Slot;
   if (!searchRange(MBB, ++SlotI.getReverse(), MBB.rend(), RegDU, MemDU, Slot,
-                   Filler))
+                   Filler)) {
+    LLVM_DEBUG(dbgs() << DEBUG_TYPE ": could not find instruction for delay "
+                                    "slot using backwards search.\n");
     return false;
+  }
 
   MBB.splice(std::next(SlotI), &MBB, Filler.getReverse());
   MIBundleBuilder(MBB, SlotI, std::next(SlotI, 2));
@@ -773,8 +806,11 @@ bool MipsDelaySlotFiller::searchForward(MachineBasicBlock &MBB,
 
   RegDU.setCallerSaved(*Slot);
 
-  if (!searchRange(MBB, std::next(Slot), MBB.end(), RegDU, NM, Slot, Filler))
+  if (!searchRange(MBB, std::next(Slot), MBB.end(), RegDU, NM, Slot, Filler)) {
+    LLVM_DEBUG(dbgs() << DEBUG_TYPE ": could not find instruction for delay "
+                                    "slot using forwards search.\n");
     return false;
+  }
 
   MBB.splice(std::next(Slot), &MBB, Filler);
   MIBundleBuilder(MBB, Slot, std::next(Slot, 2));
@@ -927,4 +963,6 @@ bool MipsDelaySlotFiller::terminateSearch(const MachineInstr &Candidate) const {
 
 /// createMipsDelaySlotFillerPass - Returns a pass that fills in delay
 /// slots in Mips MachineFunctions
-FunctionPass *llvm::createMipsDelaySlotFillerPass() { return new MipsDelaySlotFiller(); }
+FunctionPass *llvm::createMipsDelaySlotFillerPass() {
+  return new MipsDelaySlotFiller();
+}