1 files changed, 26 insertions, 12 deletions

diff --git a/lib/CodeGen/TailDuplicator.cpp b/lib/CodeGen/TailDuplicator.cpp
index f51c884839b3..b118c176a897 100644
--- a/lib/CodeGen/TailDuplicator.cpp
+++ b/lib/CodeGen/TailDuplicator.cpp
@@ -37,6 +37,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetMachine.h"
 #include <algorithm>
 #include <cassert>
 #include <iterator>
@@ -261,7 +262,7 @@ bool TailDuplicator::tailDuplicateBlocks() {
   bool MadeChange = false;
 
   if (PreRegAlloc && TailDupVerify) {
-    DEBUG(dbgs() << "\n*** Before tail-duplicating\n");
+    LLVM_DEBUG(dbgs() << "\n*** Before tail-duplicating\n");
     VerifyPHIs(*MF, true);
   }
 
@@ -371,6 +372,13 @@ void TailDuplicator::duplicateInstruction(
     MachineInstr *MI, MachineBasicBlock *TailBB, MachineBasicBlock *PredBB,
     DenseMap<unsigned, RegSubRegPair> &LocalVRMap,
     const DenseSet<unsigned> &UsedByPhi) {
+  // Allow duplication of CFI instructions.
+  if (MI->isCFIInstruction()) {
+    BuildMI(*PredBB, PredBB->end(), PredBB->findDebugLoc(PredBB->begin()),
+      TII->get(TargetOpcode::CFI_INSTRUCTION)).addCFIIndex(
+      MI->getOperand(0).getCFIIndex());
+    return;
+  }
   MachineInstr &NewMI = TII->duplicate(*PredBB, PredBB->end(), *MI);
   if (PreRegAlloc) {
     for (unsigned i = 0, e = NewMI.getNumOperands(); i != e; ++i) {
@@ -585,7 +593,13 @@ bool TailDuplicator::shouldTailDuplicate(bool IsSimple,
   unsigned InstrCount = 0;
   for (MachineInstr &MI : TailBB) {
     // Non-duplicable things shouldn't be tail-duplicated.
-    if (MI.isNotDuplicable())
+    // CFI instructions are marked as non-duplicable, because Darwin compact
+    // unwind info emission can't handle multiple prologue setups. In case of
+    // DWARF, allow them be duplicated, so that their existence doesn't prevent
+    // tail duplication of some basic blocks, that would be duplicated otherwise.
+    if (MI.isNotDuplicable() &&
+        (TailBB.getParent()->getTarget().getTargetTriple().isOSDarwin() ||
+        !MI.isCFIInstruction()))
       return false;
 
     // Convergent instructions can be duplicated only if doing so doesn't add
@@ -605,7 +619,7 @@ bool TailDuplicator::shouldTailDuplicate(bool IsSimple,
     if (PreRegAlloc && MI.isCall())
       return false;
 
-    if (!MI.isPHI() && !MI.isDebugValue())
+    if (!MI.isPHI() && !MI.isMetaInstruction())
       InstrCount += 1;
 
     if (InstrCount > MaxDuplicateCount)
@@ -704,8 +718,8 @@ bool TailDuplicator::duplicateSimpleBB(
       continue;
 
     Changed = true;
-    DEBUG(dbgs() << "\nTail-duplicating into PredBB: " << *PredBB
-                 << "From simple Succ: " << *TailBB);
+    LLVM_DEBUG(dbgs() << "\nTail-duplicating into PredBB: " << *PredBB
+                      << "From simple Succ: " << *TailBB);
 
     MachineBasicBlock *NewTarget = *TailBB->succ_begin();
     MachineBasicBlock *NextBB = PredBB->getNextNode();
@@ -785,8 +799,8 @@ bool TailDuplicator::tailDuplicate(bool IsSimple, MachineBasicBlock *TailBB,
                                    MachineBasicBlock *ForcedLayoutPred,
                                    SmallVectorImpl<MachineBasicBlock *> &TDBBs,
                                    SmallVectorImpl<MachineInstr *> &Copies) {
-  DEBUG(dbgs() << "\n*** Tail-duplicating " << printMBBReference(*TailBB)
-               << '\n');
+  LLVM_DEBUG(dbgs() << "\n*** Tail-duplicating " << printMBBReference(*TailBB)
+                    << '\n');
 
   DenseSet<unsigned> UsedByPhi;
   getRegsUsedByPHIs(*TailBB, &UsedByPhi);
@@ -816,8 +830,8 @@ bool TailDuplicator::tailDuplicate(bool IsSimple, MachineBasicBlock *TailBB,
     if (IsLayoutSuccessor)
       continue;
 
-    DEBUG(dbgs() << "\nTail-duplicating into PredBB: " << *PredBB
-                 << "From Succ: " << *TailBB);
+    LLVM_DEBUG(dbgs() << "\nTail-duplicating into PredBB: " << *PredBB
+                      << "From Succ: " << *TailBB);
 
     TDBBs.push_back(PredBB);
 
@@ -879,8 +893,8 @@ bool TailDuplicator::tailDuplicate(bool IsSimple, MachineBasicBlock *TailBB,
       (!PriorTBB || PriorTBB == TailBB) &&
       TailBB->pred_size() == 1 &&
       !TailBB->hasAddressTaken()) {
-    DEBUG(dbgs() << "\nMerging into block: " << *PrevBB
-                 << "From MBB: " << *TailBB);
+    LLVM_DEBUG(dbgs() << "\nMerging into block: " << *PrevBB
+                      << "From MBB: " << *TailBB);
     // There may be a branch to the layout successor. This is unlikely but it
     // happens. The correct thing to do is to remove the branch before
     // duplicating the instructions in all cases.
@@ -985,7 +999,7 @@ void TailDuplicator::removeDeadBlock(
     MachineBasicBlock *MBB,
     function_ref<void(MachineBasicBlock *)> *RemovalCallback) {
   assert(MBB->pred_empty() && "MBB must be dead!");
-  DEBUG(dbgs() << "\nRemoving MBB: " << *MBB);
+  LLVM_DEBUG(dbgs() << "\nRemoving MBB: " << *MBB);
 
   if (RemovalCallback)
     (*RemovalCallback)(MBB);