diff --git a/llvm/include/llvm/Analysis/MemoryProfileInfo.h b/llvm/include/llvm/Analysis/MemoryProfileInfo.h
index 571caf95f275d..be690a49767b4 100644
--- a/llvm/include/llvm/Analysis/MemoryProfileInfo.h
+++ b/llvm/include/llvm/Analysis/MemoryProfileInfo.h
@@ -59,6 +59,14 @@ LLVM_ABI std::string getAllocTypeAttributeString(AllocationType Type);
 /// True if the AllocTypes bitmask contains just a single type.
 LLVM_ABI bool hasSingleAllocType(uint8_t AllocTypes);
 
+/// Removes any existing "ambiguous" memprof attribute. Called before we apply a
+/// specific allocation type such as "cold", "notcold", or "hot".
+LLVM_ABI void removeAnyExistingAmbiguousAttribute(CallBase *CB);
+
+/// Adds an "ambiguous" memprof attribute to call with a matched allocation
+/// profile but that we haven't yet been able to disambiguate.
+LLVM_ABI void addAmbiguousAttribute(CallBase *CB);
+
 /// Class to build a trie of call stack contexts for a particular profiled
 /// allocation call, along with their associated allocation types.
 /// The allocation will be at the root of the trie, which is then used to
diff --git a/llvm/lib/Analysis/MemoryProfileInfo.cpp b/llvm/lib/Analysis/MemoryProfileInfo.cpp
index b3c8a7d4563b7..b5ca6b13108fe 100644
--- a/llvm/lib/Analysis/MemoryProfileInfo.cpp
+++ b/llvm/lib/Analysis/MemoryProfileInfo.cpp
@@ -121,6 +121,24 @@ bool llvm::memprof::hasSingleAllocType(uint8_t AllocTypes) {
   return NumAllocTypes == 1;
 }
 
+void llvm::memprof::removeAnyExistingAmbiguousAttribute(CallBase *CB) {
+  if (!CB->hasFnAttr("memprof"))
+    return;
+  assert(CB->getFnAttr("memprof").getValueAsString() == "ambiguous");
+  CB->removeFnAttr("memprof");
+}
+
+void llvm::memprof::addAmbiguousAttribute(CallBase *CB) {
+  // We may have an existing ambiguous attribute if we are reanalyzing
+  // after inlining.
+  if (CB->hasFnAttr("memprof")) {
+    assert(CB->getFnAttr("memprof").getValueAsString() == "ambiguous");
+  } else {
+    auto A = llvm::Attribute::get(CB->getContext(), "memprof", "ambiguous");
+    CB->addFnAttr(A);
+  }
+}
+
 void CallStackTrie::addCallStack(
     AllocationType AllocType, ArrayRef<uint64_t> StackIds,
     std::vector<ContextTotalSize> ContextSizeInfo) {
@@ -466,6 +484,9 @@ void CallStackTrie::addSingleAllocTypeAttribute(CallBase *CI, AllocationType AT,
                                                 StringRef Descriptor) {
   auto AllocTypeString = getAllocTypeAttributeString(AT);
   auto A = llvm::Attribute::get(CI->getContext(), "memprof", AllocTypeString);
+  // After inlining we may be able to convert an existing ambiguous allocation
+  // to an unambiguous one.
+  removeAnyExistingAmbiguousAttribute(CI);
   CI->addFnAttr(A);
   if (MemProfReportHintedSizes) {
     std::vector<ContextTotalSize> ContextSizeInfo;
@@ -525,6 +546,7 @@ bool CallStackTrie::buildAndAttachMIBMetadata(CallBase *CI) {
     assert(MIBCallStack.size() == 1 &&
            "Should only be left with Alloc's location in stack");
     CI->setMetadata(LLVMContext::MD_memprof, MDNode::get(Ctx, MIBNodes));
+    addAmbiguousAttribute(CI);
     return true;
   }
   // If there exists corner case that CallStackTrie has one chain to leaf
diff --git a/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp b/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp
index b8c99f1f33891..7f9693169af0c 100644
--- a/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp
+++ b/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp
@@ -3965,6 +3965,7 @@ void CallsiteContextGraph<DerivedCCG, FuncTy, CallTy>::identifyClones(
 void ModuleCallsiteContextGraph::updateAllocationCall(
     CallInfo &Call, AllocationType AllocType) {
   std::string AllocTypeString = getAllocTypeAttributeString(AllocType);
+  removeAnyExistingAmbiguousAttribute(cast<CallBase>(Call.call()));
   auto A = llvm::Attribute::get(Call.call()->getFunction()->getContext(),
                                 "memprof", AllocTypeString);
   cast<CallBase>(Call.call())->addFnAttr(A);
@@ -5501,6 +5502,7 @@ bool MemProfContextDisambiguation::applyImport(Module &M) {
               // clone J-1 (J==0 is the original clone and does not have a VMaps
               // entry).
               CBClone = cast<CallBase>((*VMaps[J - 1])[CB]);
+            removeAnyExistingAmbiguousAttribute(CBClone);
             CBClone->addFnAttr(A);
             ORE.emit(OptimizationRemark(DEBUG_TYPE, "MemprofAttribute", CBClone)
                      << ore::NV("AllocationCall", CBClone) << " in clone "
diff --git a/llvm/unittests/Analysis/MemoryProfileInfoTest.cpp b/llvm/unittests/Analysis/MemoryProfileInfoTest.cpp
index aa4d712cde09e..8c4fd8bb449d5 100644
--- a/llvm/unittests/Analysis/MemoryProfileInfoTest.cpp
+++ b/llvm/unittests/Analysis/MemoryProfileInfoTest.cpp
@@ -228,7 +228,8 @@ declare dso_local noalias noundef i8* @malloc(i64 noundef)
   CallBase *Call = findCall(*Func, "call");
   Trie.buildAndAttachMIBMetadata(Call);
 
-  EXPECT_FALSE(Call->hasFnAttr("memprof"));
+  EXPECT_TRUE(Call->hasFnAttr("memprof"));
+  EXPECT_EQ(Call->getFnAttr("memprof").getValueAsString(), "ambiguous");
   EXPECT_TRUE(Call->hasMetadata(LLVMContext::MD_memprof));
   MDNode *MemProfMD = Call->getMetadata(LLVMContext::MD_memprof);
   ASSERT_EQ(MemProfMD->getNumOperands(), 2u);
@@ -277,7 +278,8 @@ declare dso_local noalias noundef i8* @malloc(i64 noundef)
   CallBase *Call = findCall(*Func, "call");
   Trie.buildAndAttachMIBMetadata(Call);
 
-  EXPECT_FALSE(Call->hasFnAttr("memprof"));
+  EXPECT_TRUE(Call->hasFnAttr("memprof"));
+  EXPECT_EQ(Call->getFnAttr("memprof").getValueAsString(), "ambiguous");
   EXPECT_TRUE(Call->hasMetadata(LLVMContext::MD_memprof));
   MDNode *MemProfMD = Call->getMetadata(LLVMContext::MD_memprof);
   ASSERT_EQ(MemProfMD->getNumOperands(), 2u);
@@ -331,7 +333,8 @@ declare dso_local noalias noundef i8* @malloc(i64 noundef)
   CallBase *Call = findCall(*Func, "call");
   Trie.buildAndAttachMIBMetadata(Call);
 
-  EXPECT_FALSE(Call->hasFnAttr("memprof"));
+  EXPECT_TRUE(Call->hasFnAttr("memprof"));
+  EXPECT_EQ(Call->getFnAttr("memprof").getValueAsString(), "ambiguous");
   EXPECT_TRUE(Call->hasMetadata(LLVMContext::MD_memprof));
   MDNode *MemProfMD = Call->getMetadata(LLVMContext::MD_memprof);
   ASSERT_EQ(MemProfMD->getNumOperands(), 2u);
@@ -390,7 +393,8 @@ declare dso_local noalias noundef i8* @malloc(i64 noundef)
   CallBase *Call = findCall(*Func, "call");
   Trie.buildAndAttachMIBMetadata(Call);
 
-  EXPECT_FALSE(Call->hasFnAttr("memprof"));
+  EXPECT_TRUE(Call->hasFnAttr("memprof"));
+  EXPECT_EQ(Call->getFnAttr("memprof").getValueAsString(), "ambiguous");
   EXPECT_TRUE(Call->hasMetadata(LLVMContext::MD_memprof));
   MDNode *MemProfMD = Call->getMetadata(LLVMContext::MD_memprof);
   ASSERT_EQ(MemProfMD->getNumOperands(), 2u);
@@ -461,7 +465,8 @@ declare dso_local noalias noundef i8* @malloc(i64 noundef)
   ASSERT_NE(Call, nullptr);
   Trie.buildAndAttachMIBMetadata(Call);
 
-  EXPECT_FALSE(Call->hasFnAttr("memprof"));
+  EXPECT_TRUE(Call->hasFnAttr("memprof"));
+  EXPECT_EQ(Call->getFnAttr("memprof").getValueAsString(), "ambiguous");
   EXPECT_TRUE(Call->hasMetadata(LLVMContext::MD_memprof));
   MDNode *MemProfMD = Call->getMetadata(LLVMContext::MD_memprof);
   EXPECT_THAT(MemProfMD, MemprofMetadataEquals(ExpectedVals));
@@ -534,7 +539,8 @@ declare dso_local noalias noundef i8* @malloc(i64 noundef)
   // Restore original option value.
   MemProfKeepAllNotColdContexts = OrigMemProfKeepAllNotColdContexts;
 
-  EXPECT_FALSE(Call->hasFnAttr("memprof"));
+  EXPECT_TRUE(Call->hasFnAttr("memprof"));
+  EXPECT_EQ(Call->getFnAttr("memprof").getValueAsString(), "ambiguous");
   EXPECT_TRUE(Call->hasMetadata(LLVMContext::MD_memprof));
   MDNode *MemProfMD = Call->getMetadata(LLVMContext::MD_memprof);
   EXPECT_THAT(MemProfMD, MemprofMetadataEquals(ExpectedVals));
@@ -662,7 +668,8 @@ declare dso_local noalias noundef i8* @malloc(i64 noundef)
   // The hot allocations will be converted to NotCold and pruned as they
   // are unnecessary to determine how to clone the cold allocation.
 
-  EXPECT_FALSE(Call->hasFnAttr("memprof"));
+  EXPECT_TRUE(Call->hasFnAttr("memprof"));
+  EXPECT_EQ(Call->getFnAttr("memprof").getValueAsString(), "ambiguous");
   EXPECT_TRUE(Call->hasMetadata(LLVMContext::MD_memprof));
   MemProfMD = Call->getMetadata(LLVMContext::MD_memprof);
   ASSERT_EQ(MemProfMD->getNumOperands(), 2u);