Index: lib/CodeGen/LiveDebugValues.cpp
===================================================================
--- lib/CodeGen/LiveDebugValues.cpp
+++ lib/CodeGen/LiveDebugValues.cpp
@@ -37,6 +37,10 @@
 
 #define DEBUG_TYPE "live-debug-values"
 
+static cl::opt<bool>
+EnableLDV("live-debug-values", cl::init(true),
+          cl::desc("Enable the live debug values pass"), cl::Hidden);
+
 STATISTIC(NumInserted, "Number of DBG_VALUE instructions inserted");
 
 namespace {
@@ -360,9 +364,16 @@
       transfer(MI, OpenRanges, OutLocs);
   DEBUG(printVarLocInMBB(OutLocs, "OutLocs after initialization", dbgs()));
 
-  // Construct a worklist of MBBs.
-  for (auto &MBB : MF)
+  // Convergence takes really long time on certain programs with huge number of
+  // basic blocks. Stop converging after few iterations for every mbb.
+  const unsigned MAX_ITERS_TO_CONVERGE = 10;
+  DenseMap <MachineBasicBlock*, unsigned> StopConvergence;
+
+  // Construct a worklist of MBBs. Also initialze StopConvergence for every mbb.
+  for (auto &MBB : MF) {
     BBWorklist.push_back(&MBB);
+    StopConvergence.insert(std::make_pair(&MBB, 1));
+  }
 
   // Perform join() and transfer() using the worklist until the ranges converge
   // Ranges have converged when the worklist is empty.
@@ -379,7 +390,7 @@
       DEBUG(printVarLocInMBB(OutLocs, "OutLocs after propagating", dbgs()));
       DEBUG(printVarLocInMBB(InLocs, "InLocs after propagating", dbgs()));
 
-      if (OLChanged) {
+      if (OLChanged && (++StopConvergence[MBB] < MAX_ITERS_TO_CONVERGE)) {
         OLChanged = false;
         for (auto s : MBB->successors())
           if (std::find(BBWorklist.begin(), BBWorklist.end(), s) ==
@@ -394,6 +405,9 @@
 }
 
 bool LiveDebugValues::runOnMachineFunction(MachineFunction &MF) {
+  if (!EnableLDV)
+    return false;
+
   TRI = MF.getSubtarget().getRegisterInfo();
   TII = MF.getSubtarget().getInstrInfo();