[IRSim][IROutliner] Treating Called Functions as Values and Outlining Indirect Calls

[AndrewLitteken]

Summary

The outliner currently requires that function calls not be indirect calls, and have that the function name, and function type must match, as well as other attributes such as calling conventions. This patch treats called functions as values, and just another operand, and named function calls as constants. This allows functions to be treated like any other constant, or input and output into the outlined functions.

There are also debugging flags added to enforce the old behaviors where indirect calls not be allowed, and to enforce the old rule that function calls names must also match.

[paquette]

llvm/include/llvm/Analysis/IRSimilarityIdentifier.h

132

133

Can the comment include what this actually is used for?

205

Can the comment explain why you would/wouldn't match by name?

[AndrewLitteken]

Updating details in the comments.

[jroelofs]

llvm/include/llvm/Analysis/IRSimilarityIdentifier.h

139

I think CalleeName would be a better name for this.

211

Likewise, this should probably be: setCalleeName

[AndrewLitteken]

Changing name of function.

[paquette]

I mostly have nits at this point, so I think this is more or less good to go.

llvm/include/llvm/Analysis/IRSimilarityIdentifier.h

516

Pull CI.isIndirectCall() into a variable?

llvm/include/llvm/Transforms/IPO/IROutliner.h

370

Pull CI.isIndirectCall() into a variable?

llvm/lib/Analysis/IRSimilarityIdentifier.cpp

115

Why not replace this with a getCalleeName function? That could also assert that you actually did set the callee name as well.

186

Shouldn't this comment say "if the instructions are function calls"?

[AndrewLitteken]

updating nits

[paquette]

LGTM with typo fix

llvm/lib/Analysis/IRSimilarityIdentifier.cpp

133–134

llvm/include/llvm/Analysis/IRSimilarityIdentifier.h

struct IRInstructionData
   /// considered similar.
   bool Legal;
 
   /// This is only relevant if we are wrapping a CmpInst where we needed to
   /// change the predicate of a compare instruction from a greater than form
   /// to a less than form.  It is None otherwise.
   Optional<CmpInst::Predicate> RevisedPredicate;
 
+  /// This is only relevant if we are wrapping a CallInst. If we are requiring
+  /// that the function calls have matching names as well as types, and the
+  /// call is not an indirect call, this will hold the name of the function.  If
+  /// it is an indirect string, it will be the empty string.  However, if this
+  /// requirement is not in place it will be the empty string regardless of the
+  /// function call type.  The value held here is used to create the hash of the
+  /// instruction, and check to make sure two instructions are close to one
+  /// another.
+  Optional<std::string> CalleeName;
+
   /// This structure holds the distances of how far "ahead of" or "behind" the
   /// target blocks of a branch, or the incoming blocks of a phi nodes are.
   /// If the value is negative, it means that the block was registered before
   /// the block of this instruction in terms of blocks in the function.
   /// Code Example:
   /// \code
   /// block_1:
   ///   br i1 %0, label %block_2, label %block_3
struct IRInstructionData
   /// the difference of the number assigned to the current basic block and the
   /// target basic block of the branch.
   ///
   /// \param BasicBlockToInteger - The mapping of basic blocks to their location
   /// in the module.
   void
   setBranchSuccessors(DenseMap<BasicBlock *, unsigned> &BasicBlockToInteger);
 
+  /// For an IRInstructionData containing a CallInst, set the function name
+  /// appropriately.  This will be an empty string if it is an indirect call,
+  /// or we are not matching by name of the called function.  It will be the
+  /// name of the function if \p MatchByName is true and it is not an indirect
+  /// call.  We may decide not to match by name in order to expand the
+  /// size of the regions we can match.  If a function name has the same type
+  /// signature, but the different name, the region of code is still almost the
+  /// same.  Since function names can be treated as constants, the name itself
+  /// could be extrapolated away.  However, matching by name provides a
+  /// specificity and more "identical" code than not matching by name.
+  ///
+  /// \param MatchByName - A flag to mark whether we are using the called
+  /// function name as a differentiating parameter.
+  void setCalleeName(bool MatchByName = true);
+
   /// Hashes \p Value based on its opcode, types, and operand types.
   /// Two IRInstructionData instances produce the same hash when they perform
   /// the same operation.
   ///
   /// As a simple example, consider the following instructions.
   ///
   /// \code
   /// %add1 = add i32 %x1, %y1
for (Value *V : ID.OperVals)
       OperTypes.push_back(V->getType());
 
     if (isa<CmpInst>(ID.Inst))
       return llvm::hash_combine(
           llvm::hash_value(ID.Inst->getOpcode()),
           llvm::hash_value(ID.Inst->getType()),
           llvm::hash_value(ID.getPredicate()),
           llvm::hash_combine_range(OperTypes.begin(), OperTypes.end()));
-    else if (CallInst *CI = dyn_cast<CallInst>(ID.Inst))
+    else if (CallInst *CI = dyn_cast<CallInst>(ID.Inst)) {
+      std::string FunctionName = *ID.CalleeName;
       return llvm::hash_combine(
           llvm::hash_value(ID.Inst->getOpcode()),
-          llvm::hash_value(ID.Inst->getType()),
-          llvm::hash_value(CI->getCalledFunction()->getName().str()),
+          llvm::hash_value(ID.Inst->getType()), llvm::hash_value(FunctionName),
           llvm::hash_combine_range(OperTypes.begin(), OperTypes.end()));
+    }
     return llvm::hash_combine(
         llvm::hash_value(ID.Inst->getOpcode()),
         llvm::hash_value(ID.Inst->getType()),
         llvm::hash_combine_range(OperTypes.begin(), OperTypes.end()));
   }
 
   IRInstructionDataList *IDL = nullptr;
 };
struct IRInstructionMapper {
 
   /// Marks whether we found a illegal instruction in the previous step.
   bool CanCombineWithPrevInstr = false;
 
   /// Marks whether we have found a set of instructions that is long enough
   /// to be considered for similarity.
   bool HaveLegalRange = false;
 
+  /// Marks whether we should use exact function names, as well as types to
+  /// find similarity between calls.
+  bool EnableMatchCallsByName = false;
+
   /// This allocator pointer is in charge of holding on to the IRInstructionData
   /// so it is not deallocated until whatever external tool is using it is done
   /// with the information.
   SpecificBumpPtrAllocator<IRInstructionData> *InstDataAllocator = nullptr;
 
   /// This allocator pointer is in charge of creating the IRInstructionDataList
   /// so it is not deallocated until whatever external tool is using it is done
   /// with the information.
struct InstructionClassification
     // program.
     InstrType visitDbgInfoIntrinsic(DbgInfoIntrinsic &DII) { return Invisible; }
     // TODO: Handle specific intrinsics.
     InstrType visitIntrinsicInst(IntrinsicInst &II) { return Illegal; }
     // We only allow call instructions where the function has a name and
     // is not an indirect call.
     InstrType visitCallInst(CallInst &CI) {
       Function *F = CI.getCalledFunction();
-      if (!F || CI.isIndirectCall() || !F->hasName())
+      if (CI.isIndirectCall() && !EnableIndirectCalls)
+        return Illegal;
+      if (!F && !CI.isIndirectCall())
         return Illegal;
       return Legal;
     }
     // TODO: We do not current handle similarity that changes the control flow.
     InstrType visitInvokeInst(InvokeInst &II) { return Illegal; }
     // TODO: We do not current handle similarity that changes the control flow.
     InstrType visitCallBrInst(CallBrInst &CBI) { return Illegal; }
     // TODO: Handle interblock similarity.
     InstrType visitTerminator(Instruction &I) { return Illegal; }
     InstrType visitInstruction(Instruction &I) { return Legal; }
 
     // The flag variable that lets the classifier know whether we should
     // allow branches to be checked for similarity.
     bool EnableBranches = false;
+
+    // The flag variable that lets the classifier know whether we should
+    // allow indirect calls to be considered legal instructions.
+    bool EnableIndirectCalls = false;
   };
 
   /// Maps an Instruction to a member of InstrType.
   InstructionClassification InstClassifier;
 };
 
 /// This is a class that wraps a range of IRInstructionData from one point to
 /// another in the vector of IRInstructionData, which is a region of the

 ///
 /// SimilarityGroup 1:  SimilarityGroup 2
 /// A, B, D             C
 ///
 /// A list of the different similarity groups is then returned after
 /// analyzing the module.
 class IRSimilarityIdentifier {
 public:
-  IRSimilarityIdentifier(bool MatchBranches = true)
+  IRSimilarityIdentifier(bool MatchBranches = true,
+                         bool MatchIndirectCalls = true,
+                         bool MatchCallsWithName = false)
       : Mapper(&InstDataAllocator, &InstDataListAllocator),
-        EnableBranches(MatchBranches) {}
+        EnableBranches(MatchBranches), EnableIndirectCalls(MatchIndirectCalls),
+        EnableMatchingCallsByName(MatchCallsWithName) {}
 
 private:
   /// Map the instructions in the module to unsigned integers, using mapping
   /// already present in the Mapper if possible.
   ///
   /// \param [in] M Module - To map to integers.
   /// \param [in,out] InstrList - The vector to append IRInstructionData to.
   /// \param [in,out] IntegerMapping - The vector to append integers to.
private:
   /// Map Instructions to unsigned integers and wraps the Instruction in an
   /// instance of IRInstructionData.
   IRInstructionMapper Mapper;
 
   /// The flag variable that marks whether we should check branches for
   /// similarity, or only look within basic blocks.
   bool EnableBranches = true;
 
+  /// The flag variable that marks whether we allow indirect calls to be checked
+  /// for similarity, or exclude them as a legal instruction.
+  bool EnableIndirectCalls = true;
+
+  /// The flag variable that marks whether we allow calls to be marked as
+  /// similar if they do not have the same name, only the same calling
+  /// convention, attributes and type signature.
+  bool EnableMatchingCallsByName = true;
+
   /// The SimilarityGroups found with the most recent run of \ref
   /// findSimilarity. None if there is no recent run.
   Optional<SimilarityGroupList> SimilarityCandidates;
 };
 
 } // end namespace IRSimilarity
 
 /// An analysis pass based on legacy pass manager that runs and returns

llvm/include/llvm/Transforms/IPO/IROutliner.h

struct InstructionAllowed : public InstVisitor<InstructionAllowed, bool> {
     bool visitDbgInfoIntrinsic(DbgInfoIntrinsic &DII) { return true; }
     // TODO: Handle specific intrinsics individually from those that can be
     // handled.
     bool IntrinsicInst(IntrinsicInst &II) { return false; }
     // We only handle CallInsts that are not indirect, since we cannot guarantee
     // that they have a name in these cases.
     bool visitCallInst(CallInst &CI) {
       Function *F = CI.getCalledFunction();
-      if (!F || CI.isIndirectCall() || !F->hasName())
+      if (CI.isIndirectCall() && !EnableIndirectCalls)
+        return false;
+      if (!F && !CI.isIndirectCall())
         return false;
       return true;
     }
     // TODO: Handle FreezeInsts.  Since a frozen value could be frozen inside
     // the outlined region, and then returned as an output, this will have to be
     // handled differently.
     bool visitFreezeInst(FreezeInst &CI) { return false; }
     // TODO: We do not current handle similarity that changes the control flow.
     bool visitInvokeInst(InvokeInst &II) { return false; }
     // TODO: We do not current handle similarity that changes the control flow.
     bool visitCallBrInst(CallBrInst &CBI) { return false; }
     // TODO: Handle interblock similarity.
     bool visitTerminator(Instruction &I) { return false; }
     bool visitInstruction(Instruction &I) { return true; }
 
     // The flag variable that marks whether we should allow branch instructions
     // to be outlined.
     bool EnableBranches = false;
+
+    // The flag variable that marks whether we should allow indirect calls
+    // to be outlined.
+    bool EnableIndirectCalls = true;
   };
 
   /// A InstVisitor used to exclude certain instructions from being outlined.
   InstructionAllowed InstructionClassifier;
 };
 
 /// Pass to outline similar regions.
 class IROutlinerPass : public PassInfoMixin<IROutlinerPass> {
 public:
   PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
 };
 
 } // end namespace llvm
 
 #endif // LLVM_TRANSFORMS_IPO_IROUTLINER_H

llvm/lib/Analysis/IRSimilarityIdentifier.cpp

 using namespace IRSimilarity;
 
 cl::opt<bool>
     DisableBranches("no-ir-sim-branch-matching", cl::init(false),
                     cl::ReallyHidden,
                     cl::desc("disable similarity matching, and outlining, "
                              "across branches for debugging purposes."));
 
+cl::opt<bool>
+    DisableIndirectCalls("no-ir-sim-indirect-calls", cl::init(false),
+                         cl::ReallyHidden,
+                         cl::desc("disable outlining indirect calls."));
+
+cl::opt<bool>
+    MatchCallsByName("ir-sim-calls-by-name", cl::init(false), cl::ReallyHidden,
+                     cl::desc("only allow matching call instructions if the "
+                              "name and type signature match."));
+
 IRInstructionData::IRInstructionData(Instruction &I, bool Legality,
                                      IRInstructionDataList &IDList)
     : Inst(&I), Legal(Legality), IDL(&IDList) {
   initializeInstruction();
 }
 
 void IRInstructionData::initializeInstruction() {
   // We check for whether we have a comparison instruction.  If it is, we
void IRInstructionData::setBranchSuccessors(
     DenseMap<BasicBlock *, unsigned> &BasicBlockToInteger) {
   assert(isa<BranchInst>(Inst) && "Instruction must be branch");
 
   BranchInst *BI = cast<BranchInst>(Inst);
   DenseMap<BasicBlock *, unsigned>::iterator BBNumIt;
 
   BBNumIt = BasicBlockToInteger.find(BI->getParent());
   assert(BBNumIt != BasicBlockToInteger.end() &&
-         "Could not find location for BasicBlock!");
 
   int CurrentBlockNumber = static_cast<int>(BBNumIt->second);
 
   for (BasicBlock *Successor : BI->successors()) {
     BBNumIt = BasicBlockToInteger.find(Successor);
     assert(BBNumIt != BasicBlockToInteger.end() &&
            "Could not find number for BasicBlock!");
     int OtherBlockNumber = static_cast<int>(BBNumIt->second);
 
     int Relative = OtherBlockNumber - CurrentBlockNumber;
     RelativeBlockLocations.push_back(Relative);
   }
 }
 
+void IRInstructionData::setCalleeName(bool MatchByName) {
+  CallInst *CI = dyn_cast<CallInst>(Inst);
+  assert(CI && "Instruction must be call");
+
+  CalleeName = "";
+  if (!CI->isIndirectCall() && MatchByName)
+    CalleeName = CI->getCalledFunction()->getName().str();
+}
+
 CmpInst::Predicate IRInstructionData::predicateForConsistency(CmpInst *CI) {
   switch (CI->getPredicate()) {
   case CmpInst::FCMP_OGT:
   case CmpInst::FCMP_UGT:
   case CmpInst::FCMP_OGE:
   case CmpInst::FCMP_UGE:
   case CmpInst::ICMP_SGT:
   case CmpInst::ICMP_UGT:
CmpInst::Predicate IRInstructionData::getPredicate() const {
   assert(isa<CmpInst>(Inst) &&
          "Can only get a predicate from a compare instruction");
 
   if (RevisedPredicate.hasValue())
     return RevisedPredicate.getValue();
   
   return cast<CmpInst>(Inst)->getPredicate();
 }
 
-static StringRef getCalledFunctionName(CallInst &CI) {
-  assert(CI.getCalledFunction() != nullptr && "Called Function is nullptr?");
-
-  return CI.getCalledFunction()->getName();
-}
-
 bool IRSimilarity::isClose(const IRInstructionData &A,
                            const IRInstructionData &B) {
 
   if (!A.Legal || !B.Legal)
     return false;
 
   // Check if we are performing the same sort of operation on the same types
   // but not on the same values.
   if (!A.Inst->isSameOperationAs(B.Inst)) {
if (auto *GEP = dyn_cast<GetElementPtrInst>(A.Inst)) {
     // we only care about the following operands since they must be the
     // exact same to be considered similar.
     return all_of(drop_begin(ZippedOperands),
                   [](std::tuple<llvm::Use &, llvm::Use &> R) {
                     return std::get<0>(R) == std::get<1>(R);
                   });
   }
 
   // If the instructions are functions, we make sure that the function name is
   // the same.  We already know that the types are since is isSameOperationAs is
   // true.
   if (isa<CallInst>(A.Inst) && isa<CallInst>(B.Inst)) {
-    CallInst *CIA = cast<CallInst>(A.Inst);
-    CallInst *CIB = cast<CallInst>(B.Inst);
-    if (getCalledFunctionName(*CIA).compare(getCalledFunctionName(*CIB)) != 0)
+    if (A.CalleeName->compare(*B.CalleeName) != 0)
       return false;
   }
 
   if (isa<BranchInst>(A.Inst) && isa<BranchInst>(B.Inst) &&
       A.RelativeBlockLocations.size() != B.RelativeBlockLocations.size())
     return false;
 
   return true;
unsigned IRInstructionMapper::mapToLegalUnsigned(
   // Get the integer for this instruction or give it the current
   // LegalInstrNumber.
   IRInstructionData *ID = allocateIRInstructionData(*It, true, *IDL);
   InstrListForBB.push_back(ID);
 
   if (isa<BranchInst>(*It))
     ID->setBranchSuccessors(BasicBlockToInteger);
 
+  if (isa<CallInst>(*It))
+    ID->setCalleeName(EnableMatchCallsByName);
+
   // Add to the instruction list
   bool WasInserted;
   DenseMap<IRInstructionData *, unsigned, IRInstructionDataTraits>::iterator
       ResultIt;
   std::tie(ResultIt, WasInserted) =
       InstructionIntegerMap.insert(std::make_pair(ID, LegalInstrNumber));
   unsigned INumber = ResultIt->second;
 

 
 SimilarityGroupList &IRSimilarityIdentifier::findSimilarity(
     ArrayRef<std::unique_ptr<Module>> Modules) {
   resetSimilarityCandidates();
 
   std::vector<IRInstructionData *> InstrList;
   std::vector<unsigned> IntegerMapping;
   Mapper.InstClassifier.EnableBranches = this->EnableBranches;
+  Mapper.InstClassifier.EnableIndirectCalls = EnableIndirectCalls;
+  Mapper.EnableMatchCallsByName = EnableMatchingCallsByName;
 
   populateMapper(Modules, InstrList, IntegerMapping);
   findCandidates(InstrList, IntegerMapping);
 
   return SimilarityCandidates.getValue();
 }
 
 SimilarityGroupList &IRSimilarityIdentifier::findSimilarity(Module &M) {
   resetSimilarityCandidates();
   Mapper.InstClassifier.EnableBranches = this->EnableBranches;
+  Mapper.InstClassifier.EnableIndirectCalls = EnableIndirectCalls;
+  Mapper.EnableMatchCallsByName = EnableMatchingCallsByName;
 
   std::vector<IRInstructionData *> InstrList;
   std::vector<unsigned> IntegerMapping;
 
   populateMapper(M, InstrList, IntegerMapping);
   findCandidates(InstrList, IntegerMapping);
 
   return SimilarityCandidates.getValue();
 }
 
 INITIALIZE_PASS(IRSimilarityIdentifierWrapperPass, "ir-similarity-identifier",
                 "ir-similarity-identifier", false, true)
 
 IRSimilarityIdentifierWrapperPass::IRSimilarityIdentifierWrapperPass()
     : ModulePass(ID) {
   initializeIRSimilarityIdentifierWrapperPassPass(
       *PassRegistry::getPassRegistry());
 }
 
 bool IRSimilarityIdentifierWrapperPass::doInitialization(Module &M) {
-  IRSI.reset(new IRSimilarityIdentifier(!DisableBranches));
+  IRSI.reset(new IRSimilarityIdentifier(!DisableBranches, !DisableIndirectCalls,
+                                        MatchCallsByName));
   return false;
 }
 
 bool IRSimilarityIdentifierWrapperPass::doFinalization(Module &M) {
   IRSI.reset();
   return false;
 }
 
 bool IRSimilarityIdentifierWrapperPass::runOnModule(Module &M) {
   IRSI->findSimilarity(M);
   return false;
 }
 
 AnalysisKey IRSimilarityAnalysis::Key;
 IRSimilarityIdentifier IRSimilarityAnalysis::run(Module &M,
                                                  ModuleAnalysisManager &) {
 
-  auto IRSI = IRSimilarityIdentifier(!DisableBranches);
+  auto IRSI = IRSimilarityIdentifier(!DisableBranches, !DisableIndirectCalls,
+                                     MatchCallsByName);
   IRSI.findSimilarity(M);
   return IRSI;
 }
 
 PreservedAnalyses
 IRSimilarityAnalysisPrinterPass::run(Module &M, ModuleAnalysisManager &AM) {
   IRSimilarityIdentifier &IRSI = AM.getResult<IRSimilarityAnalysis>(M);
   Optional<SimilarityGroupList> &SimilarityCandidatesOpt = IRSI.getSimilarity();

llvm/lib/Transforms/IPO/IROutliner.cpp

 
 using namespace llvm;
 using namespace IRSimilarity;
 
 // A command flag to be used for debugging to exclude branches from similarity
 // matching and outlining.
 extern cl::opt<bool> DisableBranches;
 
+// A command flag to be used for debugging to indirect calls from similarity
+// matching and outlining.
+extern cl::opt<bool> DisableIndirectCalls;
+
 // Set to true if the user wants the ir outliner to run on linkonceodr linkage
 // functions. This is false by default because the linker can dedupe linkonceodr
 // functions. Since the outliner is confined to a single module (modulo LTO),
 // this is off by default. It should, however, be the default behavior in
 // LTO.
 static cl::opt<bool> EnableLinkOnceODRIROutlining(
     "enable-linkonceodr-ir-outlining", cl::Hidden,
     cl::desc("Enable the IR outliner on linkonceodr functions"),

       updateOutputMapping(Region, Outputs.getArrayRef(), LI);
   Region.reattachCandidate();
   return true;
 }
 
 unsigned IROutliner::doOutline(Module &M) {
   // Find the possible similarity sections.
   InstructionClassifier.EnableBranches = !DisableBranches;
+  InstructionClassifier.EnableIndirectCalls = !DisableIndirectCalls;
   IRSimilarityIdentifier &Identifier = getIRSI(M);
   SimilarityGroupList &SimilarityCandidates = *Identifier.getSimilarity();
 
   // Sort them by size of extracted sections
   unsigned OutlinedFunctionNum = 0;
   // If we only have one SimilarityGroup in SimilarityCandidates, we do not have
   // to sort them by the potential number of instructions to be outlined
   if (SimilarityCandidates.size() > 1)

llvm/test/Transforms/IROutliner/illegal-indirect-calls.ll

 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -verify -iroutliner -ir-outlining-no-cost < %s | FileCheck %s
+; RUN: opt -S -verify -iroutliner -ir-outlining-no-cost --no-ir-sim-indirect-calls < %s | FileCheck %s
 
-; This test checks that we do not outline indirect calls.  We cannot guarantee
-; that we have the same name in these cases, so two indirect calls cannot
-; be considered similar.
+; This test checks that we do not outline indirect calls when it is specified
+; that we should not.
 
 declare void @f1(i32*, i32*);
 declare void @f2(i32*, i32*);
 
 define void @function1(void()* %func) {
 ; CHECK-LABEL: @function1(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4

llvm/test/Transforms/IROutliner/legal-indirect-calls.ll

+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --include-generated-funcs
+; RUN: opt -S -verify -iroutliner -ir-outlining-no-cost < %s | FileCheck %s
+
+; This test checks that we do outline indirect calls when it is not specified
+; that we should not.
+
+declare void @f1(i32*, i32*);
+declare void @f2(i32*, i32*);
+
+define void @function1(void()* %func) {
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  %c = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  store i32 4, i32* %c, align 4
+  call void %func()
+  %al = load i32, i32* %a
+  %bl = load i32, i32* %b
+  %cl = load i32, i32* %c
+  ret void
+}
+
+define void @function2(void()* %func) {
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  %c = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  store i32 4, i32* %c, align 4
+  call void %func()
+  %al = load i32, i32* %a
+  %bl = load i32, i32* %b
+  %cl = load i32, i32* %c
+  ret void
+}
+; CHECK-LABEL: @function1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]], void ()* [[FUNC:%.*]])
+; CHECK-NEXT:    ret void
+;
+;
+; CHECK-LABEL: @function2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]], void ()* [[FUNC:%.*]])
+; CHECK-NEXT:    ret void
+;
+;
+; CHECK-LABEL: define internal void  @outlined_ir_func_0(
+; CHECK-NEXT:  newFuncRoot:
+; CHECK-NEXT:    br label [[ENTRY_TO_OUTLINE:%.*]]
+; CHECK:       entry_to_outline:
+; CHECK-NEXT:    store i32 2, i32* [[TMP0:%.*]], align 4
+; CHECK-NEXT:    store i32 3, i32* [[TMP1:%.*]], align 4
+; CHECK-NEXT:    store i32 4, i32* [[TMP2:%.*]], align 4
+; CHECK-NEXT:    call void [[TMP3:%.*]]()
+; CHECK-NEXT:    [[AL:%.*]] = load i32, i32* [[TMP0]], align 4
+; CHECK-NEXT:    [[BL:%.*]] = load i32, i32* [[TMP1]], align 4
+; CHECK-NEXT:    [[CL:%.*]] = load i32, i32* [[TMP2]], align 4
+; CHECK-NEXT:    br label [[ENTRY_AFTER_OUTLINE_EXITSTUB:%.*]]
+; CHECK:       entry_after_outline.exitStub:
+; CHECK-NEXT:    ret void
+;

llvm/test/Transforms/IROutliner/outlining-call-and-indirect.ll

+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --include-generated-funcs
+; RUN: opt -S -verify -iroutliner -ir-outlining-no-cost < %s | FileCheck %s
+
+; This test checks that we do can outline indirect and regular function calls
+; when the type matches when it is not specified that the names must match.
+
+declare void @f1();
+
+define void @function1(void()* %func) {
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  %c = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  store i32 4, i32* %c, align 4
+  call void %func()
+  %al = load i32, i32* %a
+  %bl = load i32, i32* %b
+  %cl = load i32, i32* %c
+  ret void
+}
+
+define void @function2() {
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  %c = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  store i32 4, i32* %c, align 4
+  call void @f1()
+  %al = load i32, i32* %a
+  %bl = load i32, i32* %b
+  %cl = load i32, i32* %c
+  ret void
+}
+; CHECK-LABEL: @function1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]], void ()* [[FUNC:%.*]])
+; CHECK-NEXT:    ret void
+;
+;
+; CHECK-LABEL: @function2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]], void ()* @f1)
+; CHECK-NEXT:    ret void
+;
+;
+; CHECK-LABEL: define internal void @outlined_ir_func_0(
+; CHECK-NEXT:  newFuncRoot:
+; CHECK-NEXT:    br label [[ENTRY_TO_OUTLINE:%.*]]
+; CHECK:       entry_to_outline:
+; CHECK-NEXT:    store i32 2, i32* [[TMP0:%.*]], align 4
+; CHECK-NEXT:    store i32 3, i32* [[TMP1:%.*]], align 4
+; CHECK-NEXT:    store i32 4, i32* [[TMP2:%.*]], align 4
+; CHECK-NEXT:    call void [[TMP3:%.*]]()
+; CHECK-NEXT:    [[AL:%.*]] = load i32, i32* [[TMP0]], align 4
+; CHECK-NEXT:    [[BL:%.*]] = load i32, i32* [[TMP1]], align 4
+; CHECK-NEXT:    [[CL:%.*]] = load i32, i32* [[TMP2]], align 4
+; CHECK-NEXT:    br label [[ENTRY_AFTER_OUTLINE_EXITSTUB:%.*]]
+; CHECK:       entry_after_outline.exitStub:
+; CHECK-NEXT:    ret void
+;

llvm/test/Transforms/IROutliner/outlining-calls-names-must-match.ll

+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -verify -iroutliner -ir-outlining-no-cost -ir-sim-calls-by-name < %s | FileCheck %s
+
+; This test checks that we do can outline calls, but only if they have the same
+; function type and the same name.
+
+declare void @f1(i32*, i32*);
+declare void @f2(i32*, i32*);
+
+define void @function1() {
+; CHECK-LABEL: @function1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]])
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  %c = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  store i32 4, i32* %c, align 4
+  call void @f1(i32* %a, i32* %b)
+  %al = load i32, i32* %a
+  %bl = load i32, i32* %b
+  %cl = load i32, i32* %c
+  ret void
+}
+
+define void @function2() {
+; CHECK-LABEL: @function2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]])
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  %c = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  store i32 4, i32* %c, align 4
+  call void @f1(i32* %a, i32* %b)
+  %al = load i32, i32* %a
+  %bl = load i32, i32* %b
+  %cl = load i32, i32* %c
+  ret void
+}
+
+define void @function3() {
+; CHECK-LABEL: @function3(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    store i32 2, i32* [[A]], align 4
+; CHECK-NEXT:    store i32 3, i32* [[B]], align 4
+; CHECK-NEXT:    store i32 4, i32* [[C]], align 4
+; CHECK-NEXT:    call void @f2(i32* [[A]], i32* [[B]])
+; CHECK-NEXT:    [[AL:%.*]] = load i32, i32* [[A]], align 4
+; CHECK-NEXT:    [[BL:%.*]] = load i32, i32* [[B]], align 4
+; CHECK-NEXT:    [[CL:%.*]] = load i32, i32* [[C]], align 4
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  %c = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  store i32 4, i32* %c, align 4
+  call void @f2(i32* %a, i32* %b)
+  %al = load i32, i32* %a
+  %bl = load i32, i32* %b
+  %cl = load i32, i32* %c
+  ret void
+}
+
+; CHECK: define internal void @outlined_ir_func_0(i32* [[ARG0:%.*]], i32* [[ARG1:%.*]], i32* [[ARG2:%.*]])
+; CHECK: entry_to_outline:
+; CHECK-NEXT:    store i32 2, i32* [[ARG0]], align 4
+; CHECK-NEXT:    store i32 3, i32* [[ARG1]], align 4
+; CHECK-NEXT:    store i32 4, i32* [[ARG2]], align 4
+; CHECK-NEXT:    call void @f1(i32* [[ARG0]], i32* [[ARG1]])
+; CHECK-NEXT:    [[AL:%.*]] = load i32, i32* [[ARG0]], align 4
+; CHECK-NEXT:    [[BL:%.*]] = load i32, i32* [[ARG1]], align 4
+; CHECK-NEXT:    [[CL:%.*]] = load i32, i32* [[ARG2]], align 4

llvm/test/Transforms/IROutliner/outlining-calls.ll

-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --include-generated-funcs
 ; RUN: opt -S -verify -iroutliner -ir-outlining-no-cost < %s | FileCheck %s
 
 ; This test checks that we do can outline calls, but only if they have the same
 ; function type and the same name.
 
 declare void @f1(i32*, i32*);
 declare void @f2(i32*, i32*);
 
 define void @function1() {
-; CHECK-LABEL: @function1(
-; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]])
-; CHECK-NEXT:    ret void
-;
 entry:
   %a = alloca i32, align 4
   %b = alloca i32, align 4
   %c = alloca i32, align 4
   store i32 2, i32* %a, align 4
   store i32 3, i32* %b, align 4
   store i32 4, i32* %c, align 4
   call void @f1(i32* %a, i32* %b)
   %al = load i32, i32* %a
   %bl = load i32, i32* %b
   %cl = load i32, i32* %c
   ret void
 }
 
 define void @function2() {
-; CHECK-LABEL: @function2(
-; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]])
-; CHECK-NEXT:    ret void
-;
 entry:
   %a = alloca i32, align 4
   %b = alloca i32, align 4
   %c = alloca i32, align 4
   store i32 2, i32* %a, align 4
   store i32 3, i32* %b, align 4
   store i32 4, i32* %c, align 4
   call void @f1(i32* %a, i32* %b)
   %al = load i32, i32* %a
   %bl = load i32, i32* %b
   %cl = load i32, i32* %c
   ret void
 }
 
 define void @function3() {
-; CHECK-LABEL: @function3(
-; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    store i32 2, i32* [[A]], align 4
-; CHECK-NEXT:    store i32 3, i32* [[B]], align 4
-; CHECK-NEXT:    store i32 4, i32* [[C]], align 4
-; CHECK-NEXT:    call void @f2(i32* [[A]], i32* [[B]])
-; CHECK-NEXT:    [[AL:%.*]] = load i32, i32* [[A]], align 4
-; CHECK-NEXT:    [[BL:%.*]] = load i32, i32* [[B]], align 4
-; CHECK-NEXT:    [[CL:%.*]] = load i32, i32* [[C]], align 4
-; CHECK-NEXT:    ret void
-;
 entry:
   %a = alloca i32, align 4
   %b = alloca i32, align 4
   %c = alloca i32, align 4
   store i32 2, i32* %a, align 4
   store i32 3, i32* %b, align 4
   store i32 4, i32* %c, align 4
   call void @f2(i32* %a, i32* %b)
   %al = load i32, i32* %a
   %bl = load i32, i32* %b
   %cl = load i32, i32* %c
   ret void
 }
 
-; CHECK: define internal void @outlined_ir_func_0(i32* [[ARG0:%.*]], i32* [[ARG1:%.*]], i32* [[ARG2:%.*]])
-; CHECK: entry_to_outline:
-; CHECK-NEXT:    store i32 2, i32* [[ARG0]], align 4
-; CHECK-NEXT:    store i32 3, i32* [[ARG1]], align 4
-; CHECK-NEXT:    store i32 4, i32* [[ARG2]], align 4
-; CHECK-NEXT:    call void @f1(i32* [[ARG0]], i32* [[ARG1]])
-; CHECK-NEXT:    [[AL:%.*]] = load i32, i32* [[ARG0]], align 4
-; CHECK-NEXT:    [[BL:%.*]] = load i32, i32* [[ARG1]], align 4
-; CHECK-NEXT:    [[CL:%.*]] = load i32, i32* [[ARG2]], align 4
+; CHECK-LABEL: @function1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]], void (i32*, i32*)* @f1)
+; CHECK-NEXT:    ret void
+;
+;
+; CHECK-LABEL: @function2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]], void (i32*, i32*)* @f1)
+; CHECK-NEXT:    ret void
+;
+;
+; CHECK-LABEL: @function3(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]], void (i32*, i32*)* @f2)
+; CHECK-NEXT:    ret void
+;
+;
+; CHECK-LABEL: define internal void @outlined_ir_func_0(
+; CHECK-NEXT:  newFuncRoot:
+; CHECK-NEXT:    br label [[ENTRY_TO_OUTLINE:%.*]]
+; CHECK:       entry_to_outline:
+; CHECK-NEXT:    store i32 2, i32* [[TMP0:%.*]], align 4
+; CHECK-NEXT:    store i32 3, i32* [[TMP1:%.*]], align 4
+; CHECK-NEXT:    store i32 4, i32* [[TMP2:%.*]], align 4
+; CHECK-NEXT:    call void [[TMP3:%.*]](i32* [[TMP0]], i32* [[TMP1]])
+; CHECK-NEXT:    [[AL:%.*]] = load i32, i32* [[TMP0]], align 4
+; CHECK-NEXT:    [[BL:%.*]] = load i32, i32* [[TMP1]], align 4
+; CHECK-NEXT:    [[CL:%.*]] = load i32, i32* [[TMP2]], align 4
+; CHECK-NEXT:    br label [[ENTRY_AFTER_OUTLINE_EXITSTUB:%.*]]
+; CHECK:       entry_after_outline.exitStub:
+; CHECK-NEXT:    ret void
+;

llvm/unittests/Analysis/IRSimilarityIdentifierTest.cpp

TEST(IRInstructionMapper, GetElementPtrDifferentInBounds) {
   IRInstructionMapper Mapper(&InstDataAllocator, &IDLAllocator);
   getVectors(*M, Mapper, InstrList, UnsignedVec);
 
   ASSERT_EQ(InstrList.size(), UnsignedVec.size());
   ASSERT_EQ(UnsignedVec.size(), static_cast<unsigned>(3));
   ASSERT_NE(UnsignedVec[0], UnsignedVec[1]);
 }
 
-// Checks that indirect call instructions are mapped to be illegal since we
-// cannot guarantee the same function in two different cases.
+// Checks that indirect call instructions are mapped to be illegal when it is
+// specified to disallow them.
 TEST(IRInstructionMapper, CallsIllegalIndirect) {
   StringRef ModuleString = R"(
                           define i32 @f(void()* %func) {
                           bb0:
                              call void %func()
                              ret i32 0
                           })";
   LLVMContext Context;
   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
 
   std::vector<IRInstructionData *> InstrList;
   std::vector<unsigned> UnsignedVec;
 
   SpecificBumpPtrAllocator<IRInstructionData> InstDataAllocator;
   SpecificBumpPtrAllocator<IRInstructionDataList> IDLAllocator;
   IRInstructionMapper Mapper(&InstDataAllocator, &IDLAllocator);
+  Mapper.InstClassifier.EnableIndirectCalls = false;
   getVectors(*M, Mapper, InstrList, UnsignedVec);
 
   ASSERT_EQ(InstrList.size(), UnsignedVec.size());
   ASSERT_EQ(UnsignedVec.size(), static_cast<unsigned>(0));
 }
 
+// Checks that indirect call instructions are mapped to be legal when it is not
+// specified to disallow them.
+TEST(IRInstructionMapper, CallsLegalIndirect) {
+  StringRef ModuleString = R"(
+                          define i32 @f(void()* %func) {
+                          bb0:
+                             call void %func()
+                             call void %func()
+                             ret i32 0
+                          })";
+  LLVMContext Context;
+  std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
+
+  std::vector<IRInstructionData *> InstrList;
+  std::vector<unsigned> UnsignedVec;
+
+  SpecificBumpPtrAllocator<IRInstructionData> InstDataAllocator;
+  SpecificBumpPtrAllocator<IRInstructionDataList> IDLAllocator;
+  IRInstructionMapper Mapper(&InstDataAllocator, &IDLAllocator);
+  Mapper.InstClassifier.EnableIndirectCalls = true;
+  getVectors(*M, Mapper, InstrList, UnsignedVec);
+
+  ASSERT_EQ(InstrList.size(), UnsignedVec.size());
+  ASSERT_EQ(UnsignedVec.size(), static_cast<unsigned>(3));
+}
+
 // Checks that a call instruction is mapped to be legal.  Here we check that
 // a call with the same name, and same types are mapped to the same
 // value.
 TEST(IRInstructionMapper, CallsSameTypeSameName) {
   StringRef ModuleString = R"(
                           declare i32 @f1(i32, i32)
                           define i32 @f(i32 %a, i32 %b) {
                           bb0:
TEST(IRInstructionMapper, CallsSameTypeSameName) {
   getVectors(*M, Mapper, InstrList, UnsignedVec);
 
   ASSERT_EQ(InstrList.size(), UnsignedVec.size());
   ASSERT_EQ(UnsignedVec.size(), static_cast<unsigned>(3));
   ASSERT_EQ(UnsignedVec[0], UnsignedVec[1]);
 }
 
 // Here we check that a calls with different names, but the same arguments types
-// are mapped to different value.
-TEST(IRInstructionMapper, CallsSameArgTypeDifferentName) {
+// are mapped to different value when specified that the name must match.
+TEST(IRInstructionMapper, CallsSameArgTypeDifferentNameDisallowed) {
   StringRef ModuleString = R"(
                           declare i32 @f1(i32, i32)
                           declare i32 @f2(i32, i32)
                           define i32 @f(i32 %a, i32 %b) {
                           bb0:
                              %0 = call i32 @f1(i32 %a, i32 %b)
                              %1 = call i32 @f2(i32 %a, i32 %b)
                              ret i32 0
                           })";
   LLVMContext Context;
   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
 
   std::vector<IRInstructionData *> InstrList;
   std::vector<unsigned> UnsignedVec;
 
   SpecificBumpPtrAllocator<IRInstructionData> InstDataAllocator;
   SpecificBumpPtrAllocator<IRInstructionDataList> IDLAllocator;
   IRInstructionMapper Mapper(&InstDataAllocator, &IDLAllocator);
+  Mapper.EnableMatchCallsByName = true;
   getVectors(*M, Mapper, InstrList, UnsignedVec);
 
   ASSERT_EQ(InstrList.size(), UnsignedVec.size());
   ASSERT_EQ(UnsignedVec.size(), static_cast<unsigned>(3));
   ASSERT_NE(UnsignedVec[0], UnsignedVec[1]);
 }
 
+// Here we check that a calls with different names, but the same arguments types
+// are mapped to the same value when it is not specifed that they must match.
+TEST(IRInstructionMapper, CallsSameArgTypeDifferentName) {
+  StringRef ModuleString = R"(
+                          declare i32 @f1(i32, i32)
+                          declare i32 @f2(i32, i32)
+                          define i32 @f(i32 %a, i32 %b) {
+                          bb0:
+                             %0 = call i32 @f1(i32 %a, i32 %b)
+                             %1 = call i32 @f2(i32 %a, i32 %b)
+                             ret i32 0
+                          })";
+  LLVMContext Context;
+  std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
+
+  std::vector<IRInstructionData *> InstrList;
+  std::vector<unsigned> UnsignedVec;
+
+  SpecificBumpPtrAllocator<IRInstructionData> InstDataAllocator;
+  SpecificBumpPtrAllocator<IRInstructionDataList> IDLAllocator;
+  IRInstructionMapper Mapper(&InstDataAllocator, &IDLAllocator);
+  Mapper.EnableMatchCallsByName = false;
+  getVectors(*M, Mapper, InstrList, UnsignedVec);
+
+  ASSERT_EQ(InstrList.size(), UnsignedVec.size());
+  ASSERT_EQ(UnsignedVec.size(), static_cast<unsigned>(3));
+  ASSERT_EQ(UnsignedVec[0], UnsignedVec[1]);
+}
+
 // Here we check that a calls with different names, and different arguments
 // types are mapped to different value.
 TEST(IRInstructionMapper, CallsDifferentArgTypeDifferentName) {
   StringRef ModuleString = R"(
                           declare i32 @f1(i32, i32)
                           declare i32 @f2(i32)
                           define i32 @f(i32 %a, i32 %b) {
                           bb0: