Index: llvm/lib/Transforms/Utils/Debugify.cpp
===================================================================
--- llvm/lib/Transforms/Utils/Debugify.cpp
+++ llvm/lib/Transforms/Utils/Debugify.cpp
@@ -51,6 +51,24 @@
 
 raw_ostream &dbg() { return Quiet ? nulls() : errs(); }
 
+enum class LimitNum : unsigned int {
+  Zero = 0,
+  Default = 10000,
+  Unlimited = UINT_MAX
+};
+
+// Limit number of processed instructions during collectDebugInfoMetadata
+// and checkDebugInfoMetadata.
+cl::opt<LimitNum> DebugifyInstrLimit(
+    "debugify-instr-limit",
+    cl::desc("Set limit for the number of observed instructions per pass."),
+    cl::values(clEnumValN(LimitNum::Zero, "zero",
+                          "Don't process any instructions"),
+               clEnumValN(LimitNum::Default, "default",
+                          "Set limit to 10000 instructions"),
+               clEnumValN(LimitNum::Unlimited, "unlimited", "No limit")),
+    cl::init(LimitNum::Default));
+
 uint64_t getAllocSizeInBits(Module &M, Type *Ty) {
   return Ty->isSized() ? M.getDataLayout().getTypeAllocSizeInBits(Ty) : 0;
 }
@@ -296,6 +314,18 @@
     return false;
   }
 
+  unsigned int InstrCounter;
+  switch (DebugifyInstrLimit) {
+  case LimitNum::Default:
+    InstrCounter = static_cast<unsigned int>(LimitNum::Default);
+    break;
+  case LimitNum::Unlimited:
+    InstrCounter = static_cast<unsigned int>(LimitNum::Unlimited);
+    break;
+  default:
+    InstrCounter = static_cast<unsigned int>(LimitNum::Zero);
+  }
+
   // Visit each instruction.
   for (Function &F : Functions) {
     if (isFunctionSkipped(F))
@@ -319,6 +349,8 @@
         // Skip PHIs.
         if (isa<PHINode>(I))
           continue;
+        if (InstrCounter-- == 0)
+          return true;
 
         // Cllect dbg.values and dbg.declare.
         if (DebugifyLevel > Level::Locations) {
@@ -533,8 +565,22 @@
   // Map the debug info holding DIs after a pass.
   DebugInfoPerPass DebugInfoAfterPass;
 
+  unsigned int InstrCounter;
+  switch (DebugifyInstrLimit) {
+  case LimitNum::Default:
+    InstrCounter = static_cast<unsigned int>(LimitNum::Default);
+    break;
+  case LimitNum::Unlimited:
+    InstrCounter = static_cast<unsigned int>(LimitNum::Unlimited);
+    break;
+  default:
+    InstrCounter = static_cast<unsigned int>(LimitNum::Zero);
+  }
+
   // Visit each instruction.
   for (Function &F : Functions) {
+    if (InstrCounter == 0)
+      break;
     if (isFunctionSkipped(F))
       continue;
 
@@ -553,11 +599,17 @@
     }
 
     for (BasicBlock &BB : F) {
+      if (InstrCounter == 0)
+        break;
       // Collect debug locations (!dbg) and debug variable intrinsics.
       for (Instruction &I : BB) {
         // Skip PHIs.
         if (isa<PHINode>(I))
           continue;
+        if (InstrCounter == 0)
+          break;
+        else
+          --InstrCounter;
 
         // Collect dbg.values and dbg.declares.
         if (DebugifyLevel > Level::Locations) {
Index: llvm/test/Transforms/Util/Debugify/loc-only-original-mode.ll
===================================================================
--- llvm/test/Transforms/Util/Debugify/loc-only-original-mode.ll
+++ llvm/test/Transforms/Util/Debugify/loc-only-original-mode.ll
@@ -2,8 +2,18 @@
 ; RUN:     -verify-each-debuginfo-preserve \
 ; RUN:     -debugify-level=locations -S 2>&1 | FileCheck %s
 
+; RUN: opt < %s -deadargelim -enable-new-pm=false \
+; RUN:     -verify-each-debuginfo-preserve \
+; RUN:     -debugify-instr-limit=zero -S 2>&1 | FileCheck %s
+
+; RUN: opt < %s -deadargelim -enable-new-pm=false \
+; RUN:     -verify-each-debuginfo-preserve -debugify-instr-limit=unlimited \
+; RUN:     -S 2>&1 | FileCheck %s --check-prefix=UNLIMITED
+
 ;; Ensure that we check for DILocation potential issues only.
 ; CHECK-NOT: drops dbg.value()/dbg.declare()
+; UNLIMITED: drops dbg.value()/dbg.declare()
+
 
 target triple = "x86_64-unknown-linux-gnu"