Enrich inline messages

[yrouban]

Summary

This patch improves Inliner to provide causes/reasons for negative inline decisions.

1. It adds one new message field to InlineCost to report causes for Always and Never instances. All Never and Always instantiations must provide a simple message.
2. Several functions that used to return the inlining results as boolean are changed to return InlineResult which carries the cause for negative decision.
3. Changed remark priniting and debug output messages to provide the additional messages and related inline cost.
4. Adjusted tests for changed printing.

Patch by: yrouban (Yevgeny Rouban)

[tejohnson]

This would be useful for my own analysis of missed inlines. A few nits.

include/llvm/Transforms/Utils/Cloning.h

219

I think this would make more sense in InlineCost.h

lib/Transforms/IPO/Inliner.cpp

422–423

nit: suggest making this:
<< " because it should never be inlined (" << IC << ")";
so that there is still a "(" delimiter before the "cost=never".

434

nit: suggest changing to:

<< NV("Caller", Caller) << " because too costly to inline with " << IC;

so that you don't end up with 2 levels of nested parentheses in messages.

[yrouban]

lib/Transforms/IPO/Inliner.cpp

434

do you mind if I put ':' before inline cost in both cases?

<< " because it should never be inlined: " << IC;
<< " because too costly to inline: " << IC;

[yrouban]

include/llvm/Transforms/Utils/Cloning.h

219

InlineCost.h relates to Analysis but InlineResult is a result of a transformations.
In other words all users of InlineResult reside in lib/Transforms.
But I do not insist.

[yrouban]

Updated delimiters in output as requested.

[tejohnson]

include/llvm/Transforms/Utils/Cloning.h

219

It seems to mostly be related to analysis though, so Cloning.h seems to be the wrong place IMO. Mostly this structure is created by InlineCost.cpp (although I see it is also created by InlineFunction.cpp in some cases).

Also, I believe it is wrong to include a Transforms header into an Analysis cpp file, whereas the reverse is fine (I just checked and this would be the first Transforms header in any Analysis cpp file).

lib/Transforms/IPO/Inliner.cpp

434

Colon looks good here in the too costly to inline case. Slight preference for the parentheses in the earlier case, just around the "cost=never", to avoid the 2 sets of ":". I.e. so that it looks like:
foz not inlined into bar because it should never be inlined (cost=never): noinline function attribute (hotness: 30)

[yrouban]

1. formatted
2. moved InlineResult from Cloning.h to InlineCost.h
3. changed InlineCost printing to (cost=X, threshold=Y) or (cost=never): message or (cost=always): message. Had to fix many test checks.

[tejohnson]

LGTM

[xbolva00]

lib/Transforms/IPO/Inliner.cpp

373

stringstream?

[yrouban]

Minor change: got got rid of multiple string operators += in inlineCostStr() by reusing the output stream template for printing InlineCost.

[yrouban]

I have just made checked with the latest trunk.
Committers! could anyone land this patch please?

[xbolva00]

In D49412#1181668, @yrouban wrote:

I have just made checked with the latest trunk.
Committers! could anyone land this patch please?

Sadly, bot fails
http://lab.llvm.org:8011/builders/lldb-x86_64-ubuntu-14.04-buildserver/builds/27265/steps/ninja%20build%20local/logs/stdio

[yrouban]

In D49412#1182419, @xbolva00 wrote:

Sadly, bot fails
http://lab.llvm.org:8011/builders/lldb-x86_64-ubuntu-14.04-buildserver/builds/27265/steps/ninja%20build%20local/logs/stdio

Started looking at the failure.

[yrouban]

Fixed the buildbot failure (clang++ compilation error) by putting the operator<<(.., NV &Arg) before the template operator<<(.., InlineCost) in Inliner.cpp.

[xbolva00]

In D49412#1183876, @yrouban wrote:

Fixed the buildbot failure (clang++ compilation error) by putting the operator<<(.., NV &Arg) before the template operator<<(.., InlineCost) in Inliner.cpp.

Re-landed

[xbolva00]

Clang and lld tests fail
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/34124

Please update them, run ninja check-all

[yrouban]

In D49412#1183972, @xbolva00 wrote:

Clang and lld tests fail
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/34124

The fixes seem to be simple, but I need to set up and build additional projects.
How can I submit patches to several projects that should be synchronously updated?

[xbolva00]

In D49412#1185231, @yrouban wrote:

In D49412#1183972, @xbolva00 wrote:

Clang and lld tests fail
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/34124

The fixes seem to be simple, but I need to set up and build additional projects.
How can I submit patches to several projects that should be synchronously updated?

Just prepare patches for Clang and LLD, We merge them + this one at the same time (some bot failures are expected, but after some time it should be okay)

[xbolva00]

And.. Set this patch as dependency for Clang and LLD patches :)

[xbolva00]

Ran ninja check-all with all patches - okay. So committed again. Not sure how bots/merge systems watch for dependencies, maybe I get some bot failures but after some time it should stabilize.

[xbolva00]

Bots are fine :) Thanks!

[yrouban]

In D49412#1188850, @xbolva00 wrote:

Thank you very much, Dávid!

include/llvm/Analysis/InlineCost.h

class InlineCost {
   };
 
   /// The estimated cost of inlining this callsite.
   const int Cost;
 
   /// The adjusted threshold against which this cost was computed.
   const int Threshold;
 
+  /// Must be set for Always and Never instances.
+  const char *Reason = nullptr;
+
   // Trivial constructor, interesting logic in the factory functions below.
-  InlineCost(int Cost, int Threshold) : Cost(Cost), Threshold(Threshold) {}
+  InlineCost(int Cost, int Threshold, const char *Reason = nullptr)
+      : Cost(Cost), Threshold(Threshold), Reason(Reason) {
+    assert((isVariable() || Reason) &&
+           "Reason must be provided for Never or Always");
+  }
 
 public:
   static InlineCost get(int Cost, int Threshold) {
     assert(Cost > AlwaysInlineCost && "Cost crosses sentinel value");
     assert(Cost < NeverInlineCost && "Cost crosses sentinel value");
     return InlineCost(Cost, Threshold);
   }
-  static InlineCost getAlways() {
-    return InlineCost(AlwaysInlineCost, 0);
+  static InlineCost getAlways(const char *Reason) {
+    return InlineCost(AlwaysInlineCost, 0, Reason);
   }
-  static InlineCost getNever() {
-    return InlineCost(NeverInlineCost, 0);
+  static InlineCost getNever(const char *Reason) {
+    return InlineCost(NeverInlineCost, 0, Reason);
   }
 
   /// Test whether the inline cost is low enough for inlining.
   explicit operator bool() const {
     return Cost < Threshold;
   }
 
   bool isAlways() const { return Cost == AlwaysInlineCost; }
   bool isNever() const { return Cost == NeverInlineCost; }
   bool isVariable() const { return !isAlways() && !isNever(); }
 
   /// Get the inline cost estimate.
   /// It is an error to call this on an "always" or "never" InlineCost.
   int getCost() const {
     assert(isVariable() && "Invalid access of InlineCost");
     return Cost;
   }
 
   /// Get the threshold against which the cost was computed
   int getThreshold() const {
     assert(isVariable() && "Invalid access of InlineCost");
     return Threshold;
   }
 
+  /// Get the reason of Always or Never.
+  const char *getReason() const {
+    assert((Reason || isVariable()) &&
+           "InlineCost reason must be set for Always or Never");
+    return Reason;
+  }
+
   /// Get the cost delta from the threshold for inlining.
   /// Only valid if the cost is of the variable kind. Returns a negative
   /// value if the cost is too high to inline.
   int getCostDelta() const { return Threshold - getCost(); }
 };
 
+/// InlineResult is basically true or false. For false results the message
+/// describes a reason why it is decided not to inline.
+struct InlineResult {
+  const char *message = nullptr;
+  InlineResult(bool result, const char *message = nullptr)
+      : message(result ? nullptr : (message ? message : "cost > threshold")) {}
+  InlineResult(const char *message = nullptr) : message(message) {}
+  operator bool() const { return !message; }
+  operator const char *() const { return message; }
+};
+
 /// Thresholds to tune inline cost analysis. The inline cost analysis decides
 /// the condition to apply a threshold and applies it. Otherwise,
 /// DefaultThreshold is used. If a threshold is Optional, it is applied only
 /// when it has a valid value. Typically, users of inline cost analysis
 /// obtain an InlineParams object through one of the \c getInlineParams methods
 /// and pass it to \c getInlineCost. Some specialized versions of inliner
 /// (such as the pre-inliner) might have custom logic to compute \c InlineParams
 /// object.

include/llvm/IR/DiagnosticInfo.h

struct Argument {
     std::string Val;
     // If set, the debug location corresponding to the value.
     DiagnosticLocation Loc;
 
     explicit Argument(StringRef Str = "") : Key("String"), Val(Str) {}
     Argument(StringRef Key, const Value *V);
     Argument(StringRef Key, const Type *T);
     Argument(StringRef Key, StringRef S);
+    Argument(StringRef Key, const char *S) : Argument(Key, StringRef(S)) {};
     Argument(StringRef Key, int N);
     Argument(StringRef Key, float N);
     Argument(StringRef Key, long N);
     Argument(StringRef Key, long long N);
     Argument(StringRef Key, unsigned N);
     Argument(StringRef Key, unsigned long N);
     Argument(StringRef Key, unsigned long long N);
     Argument(StringRef Key, bool B) : Key(Key), Val(B ? "true" : "false") {}

include/llvm/Transforms/Utils/Cloning.h

 
 #ifndef LLVM_TRANSFORMS_UTILS_CLONING_H
 #define LLVM_TRANSFORMS_UTILS_CLONING_H
 
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/InlineCost.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/ValueHandle.h"
 #include "llvm/Transforms/Utils/ValueMapper.h"
 #include <functional>
 #include <memory>
 #include <vector>
 
 namespace llvm {
void reset() {
     StaticAllocas.clear();
     InlinedCalls.clear();
     InlinedCallSites.clear();
   }
 };
 
 /// InlineFunction - This function inlines the called function into the basic
 /// block of the caller.  This returns false if it is not possible to inline
 /// this call.  The program is still in a well defined state if this occurs
 /// though.
 ///
 /// Note that this only does one level of inlining.  For example, if the
 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
 /// exists in the instruction stream.  Similarly this will inline a recursive
 /// function by one level.
 ///
 /// Note that while this routine is allowed to cleanup and optimize the
 /// *inlined* code to minimize the actual inserted code, it must not delete
 /// code in the caller as users of this routine may have pointers to
 /// instructions in the caller that need to remain stable.
 ///
 /// If ForwardVarArgsTo is passed, inlining a function with varargs is allowed
 /// and all varargs at the callsite will be passed to any calls to
 /// ForwardVarArgsTo. The caller of InlineFunction has to make sure any varargs
 /// are only used by ForwardVarArgsTo.
-bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI,
-                    AAResults *CalleeAAR = nullptr, bool InsertLifetime = true);
-bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI,
-                    AAResults *CalleeAAR = nullptr, bool InsertLifetime = true);
-bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
-                    AAResults *CalleeAAR = nullptr, bool InsertLifetime = true,
+InlineResult InlineFunction(CallInst *C, InlineFunctionInfo &IFI,
+                            AAResults *CalleeAAR = nullptr,
+                            bool InsertLifetime = true);
+InlineResult InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI,
+                            AAResults *CalleeAAR = nullptr,
+                            bool InsertLifetime = true);
+InlineResult InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
+                            AAResults *CalleeAAR = nullptr,
+                            bool InsertLifetime = true,
                             Function *ForwardVarArgsTo = nullptr);
 
 /// Clones a loop \p OrigLoop.  Returns the loop and the blocks in \p
 /// Blocks.
 ///
 /// Updates LoopInfo and DominatorTree assuming the loop is dominated by block
 /// \p LoopDomBB.  Insert the new blocks before block specified in \p Before.
 /// Note: Only innermost loops are supported.
 Loop *cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB,

lib/Analysis/InlineCost.cpp

class CallAnalyzer : public InstVisitor<CallAnalyzer, bool> {
   /// Return true if \p CS is a cold callsite.
   bool isColdCallSite(CallSite CS, BlockFrequencyInfo *CallerBFI);
 
   /// Return a higher threshold if \p CS is a hot callsite.
   Optional<int> getHotCallSiteThreshold(CallSite CS,
                                         BlockFrequencyInfo *CallerBFI);
 
   // Custom analysis routines.
-  bool analyzeBlock(BasicBlock *BB, SmallPtrSetImpl<const Value *> &EphValues);
+  InlineResult analyzeBlock(BasicBlock *BB,
+                            SmallPtrSetImpl<const Value *> &EphValues);
 
   // Disable several entry points to the visitor so we don't accidentally use
   // them by declaring but not defining them here.
   void visit(Module *);
   void visit(Module &);
   void visit(Function *);
   void visit(Function &);
   void visit(BasicBlock *);
CallAnalyzer(const TargetTransformInfo &TTI,
         HasUninlineableIntrinsic(false), UsesVarArgs(false), AllocatedSize(0),
         NumInstructions(0), NumVectorInstructions(0), VectorBonus(0),
         SingleBBBonus(0), EnableLoadElimination(true), LoadEliminationCost(0),
         NumConstantArgs(0), NumConstantOffsetPtrArgs(0), NumAllocaArgs(0),
         NumConstantPtrCmps(0), NumConstantPtrDiffs(0),
         NumInstructionsSimplified(0), SROACostSavings(0),
         SROACostSavingsLost(0) {}
 
-  bool analyzeCall(CallSite CS);
+  InlineResult analyzeCall(CallSite CS);
 
   int getThreshold() { return Threshold; }
   int getCost() { return Cost; }
 
   // Keep a bunch of stats about the cost savings found so we can print them
   // out when debugging.
   unsigned NumConstantArgs;
   unsigned NumConstantOffsetPtrArgs;

 
 /// Analyze a basic block for its contribution to the inline cost.
 ///
 /// This method walks the analyzer over every instruction in the given basic
 /// block and accounts for their cost during inlining at this callsite. It
 /// aborts early if the threshold has been exceeded or an impossible to inline
 /// construct has been detected. It returns false if inlining is no longer
 /// viable, and true if inlining remains viable.
-bool CallAnalyzer::analyzeBlock(BasicBlock *BB,
-                                SmallPtrSetImpl<const Value *> &EphValues) {
+InlineResult
+CallAnalyzer::analyzeBlock(BasicBlock *BB,
   for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
     // FIXME: Currently, the number of instructions in a function regardless of
     // our ability to simplify them during inline to constants or dead code,
     // are actually used by the vector bonus heuristic. As long as that's true,
     // we have to special case debug intrinsics here to prevent differences in
     // inlining due to debug symbols. Eventually, the number of unsimplified
     // instructions shouldn't factor into the cost computation, but until then,
     // hack around it here.
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
     // cost should count against inlining.
     if (Base::visit(&*I))
       ++NumInstructionsSimplified;
     else
       Cost += InlineConstants::InstrCost;
 
     using namespace ore;
     // If the visit this instruction detected an uninlinable pattern, abort.
-    if (IsRecursiveCall || ExposesReturnsTwice || HasDynamicAlloca ||
-        HasIndirectBr || HasUninlineableIntrinsic || UsesVarArgs) {
+    InlineResult IR;
+    if (IsRecursiveCall)
+      IR = "recursive";
+    else if (ExposesReturnsTwice)
+      IR = "exposes returns twice";
+    else if (HasDynamicAlloca)
+      IR = "dynamic alloca";
+    else if (HasIndirectBr)
+      IR = "indirect branch";
+    else if (HasUninlineableIntrinsic)
+      IR = "uninlinable intrinsic";
+    else if (UsesVarArgs)
+      IR = "varargs";
+    if (!IR) {
       if (ORE)
         ORE->emit([&]() {
           return OptimizationRemarkMissed(DEBUG_TYPE, "NeverInline",
                                           CandidateCS.getInstruction())
-                 << NV("Callee", &F)
-                 << " has uninlinable pattern and cost is not fully computed";
+                 << NV("Callee", &F) << " has uninlinable pattern ("
+                 << NV("InlineResult", IR.message)
+                 << ") and cost is not fully computed";
         });
-      return false;
+      return IR;
     }
 
     // If the caller is a recursive function then we don't want to inline
     // functions which allocate a lot of stack space because it would increase
     // the caller stack usage dramatically.
     if (IsCallerRecursive &&
         AllocatedSize > InlineConstants::TotalAllocaSizeRecursiveCaller) {
+      InlineResult IR = "recursive and allocates too much stack space";
       if (ORE)
         ORE->emit([&]() {
           return OptimizationRemarkMissed(DEBUG_TYPE, "NeverInline",
                                           CandidateCS.getInstruction())
-                 << NV("Callee", &F)
-                 << " is recursive and allocates too much stack space. Cost is "
-                    "not fully computed";
+                 << NV("Callee", &F) << " is " << NV("InlineResult", IR.message)
+                 << ". Cost is not fully computed";
         });
-      return false;
+      return IR;
     }
 
     // Check if we've past the maximum possible threshold so we don't spin in
     // huge basic blocks that will never inline.
     if (Cost >= Threshold && !ComputeFullInlineCost)
       return false;
   }
 

 
 /// Analyze a call site for potential inlining.
 ///
 /// Returns true if inlining this call is viable, and false if it is not
 /// viable. It computes the cost and adjusts the threshold based on numerous
 /// factors and heuristics. If this method returns false but the computed cost
 /// is below the computed threshold, then inlining was forcibly disabled by
 /// some artifact of the routine.
-bool CallAnalyzer::analyzeCall(CallSite CS) {
+InlineResult CallAnalyzer::analyzeCall(CallSite CS) {
   ++NumCallsAnalyzed;
 
   // Perform some tweaks to the cost and threshold based on the direct
   // callsite information.
 
   // We want to more aggressively inline vector-dense kernels, so up the
   // threshold, and we'll lower it if the % of vector instructions gets too
   // low. Note that these bonuses are some what arbitrary and evolved over time
InlineResult CallAnalyzer::analyzeCall(CallSite CS) {
 
   // If this function uses the coldcc calling convention, prefer not to inline
   // it.
   if (F.getCallingConv() == CallingConv::Cold)
     Cost += InlineConstants::ColdccPenalty;
 
   // Check if we're done. This can happen due to bonuses and penalties.
   if (Cost >= Threshold && !ComputeFullInlineCost)
-    return false;
+    return "high cost";
 
   if (F.empty())
     return true;
 
   Function *Caller = CS.getInstruction()->getFunction();
   // Check if the caller function is recursive itself.
   for (User *U : Caller->users()) {
     CallSite Site(U);
for (unsigned Idx = 0; Idx != BBWorklist.size(); ++Idx) {
 
     // Disallow inlining a blockaddress. A blockaddress only has defined
     // behavior for an indirect branch in the same function, and we do not
     // currently support inlining indirect branches. But, the inliner may not
     // see an indirect branch that ends up being dead code at a particular call
     // site. If the blockaddress escapes the function, e.g., via a global
     // variable, inlining may lead to an invalid cross-function reference.
     if (BB->hasAddressTaken())
-      return false;
+      return "blockaddress";
 
     // Analyze the cost of this block. If we blow through the threshold, this
     // returns false, and we can bail on out.
-    if (!analyzeBlock(BB, EphValues))
-      return false;
+    InlineResult IR = analyzeBlock(BB, EphValues);
+    if (!IR)
+      return IR;
 
     TerminatorInst *TI = BB->getTerminator();
 
     // Add in the live successors by first checking whether we have terminator
     // that may be simplified based on the values simplified by this call.
     if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
       if (BI->isConditional()) {
         Value *Cond = BI->getCondition();
InlineResult CallAnalyzer::analyzeCall(CallSite CS) {
   }
 
   bool OnlyOneCallAndLocalLinkage =
       F.hasLocalLinkage() && F.hasOneUse() && &F == CS.getCalledFunction();
   // If this is a noduplicate call, we can still inline as long as
   // inlining this would cause the removal of the caller (so the instruction
   // is not actually duplicated, just moved).
   if (!OnlyOneCallAndLocalLinkage && ContainsNoDuplicateCall)
-    return false;
+    return "noduplicate";
 
   // We applied the maximum possible vector bonus at the beginning. Now,
   // subtract the excess bonus, if any, from the Threshold before
   // comparing against Cost.
   if (NumVectorInstructions <= NumInstructions / 10)
     Threshold -= VectorBonus;
   else if (NumVectorInstructions <= NumInstructions / 2)
     Threshold -= VectorBonus/2;
InlineCost llvm::getInlineCost(
     CallSite CS, Function *Callee, const InlineParams &Params,
     TargetTransformInfo &CalleeTTI,
     std::function<AssumptionCache &(Function &)> &GetAssumptionCache,
     Optional<function_ref<BlockFrequencyInfo &(Function &)>> GetBFI,
     ProfileSummaryInfo *PSI, OptimizationRemarkEmitter *ORE) {
 
   // Cannot inline indirect calls.
   if (!Callee)
-    return llvm::InlineCost::getNever();
+    return llvm::InlineCost::getNever("indirect call");
 
   // Never inline calls with byval arguments that does not have the alloca
   // address space. Since byval arguments can be replaced with a copy to an
   // alloca, the inlined code would need to be adjusted to handle that the
   // argument is in the alloca address space (so it is a little bit complicated
   // to solve).
   unsigned AllocaAS = Callee->getParent()->getDataLayout().getAllocaAddrSpace();
   for (unsigned I = 0, E = CS.arg_size(); I != E; ++I)
     if (CS.isByValArgument(I)) {
       PointerType *PTy = cast<PointerType>(CS.getArgument(I)->getType());
       if (PTy->getAddressSpace() != AllocaAS)
-        return llvm::InlineCost::getNever();
+        return llvm::InlineCost::getNever("byval arguments without alloca"
+                                          " address space");
     }
 
   // Calls to functions with always-inline attributes should be inlined
   // whenever possible.
   if (CS.hasFnAttr(Attribute::AlwaysInline)) {
     if (isInlineViable(*Callee))
-      return llvm::InlineCost::getAlways();
-    return llvm::InlineCost::getNever();
+      return llvm::InlineCost::getAlways("always inline attribute");
+    return llvm::InlineCost::getNever("inapplicable always inline attribute");
   }
 
   // Never inline functions with conflicting attributes (unless callee has
   // always-inline attribute).
   Function *Caller = CS.getCaller();
   if (!functionsHaveCompatibleAttributes(Caller, Callee, CalleeTTI))
-    return llvm::InlineCost::getNever();
+    return llvm::InlineCost::getNever("conflicting attributes");
 
   // Don't inline this call if the caller has the optnone attribute.
   if (Caller->hasFnAttribute(Attribute::OptimizeNone))
-    return llvm::InlineCost::getNever();
+    return llvm::InlineCost::getNever("optnone attribute");
 
   // Don't inline a function that treats null pointer as valid into a caller
   // that does not have this attribute.
   if (!Caller->nullPointerIsDefined() && Callee->nullPointerIsDefined())
-    return llvm::InlineCost::getNever();
+    return llvm::InlineCost::getNever("nullptr definitions incompatible");
 
-  // Don't inline functions which can be interposed at link-time.  Don't inline
-  // functions marked noinline or call sites marked noinline.
-  // Note: inlining non-exact non-interposable functions is fine, since we know
-  // we have *a* correct implementation of the source level function.
-  if (Callee->isInterposable() || Callee->hasFnAttribute(Attribute::NoInline) ||
-      CS.isNoInline())
-    return llvm::InlineCost::getNever();
+  // Don't inline functions which can be interposed at link-time.
+  if (Callee->isInterposable())
+    return llvm::InlineCost::getNever("interposable");
+
+  // Don't inline functions marked noinline.
+  if (Callee->hasFnAttribute(Attribute::NoInline))
+    return llvm::InlineCost::getNever("noinline function attribute");
+
+  // Don't inline call sites marked noinline.
+  if (CS.isNoInline())
+    return llvm::InlineCost::getNever("noinline call site attribute");
 
   LLVM_DEBUG(llvm::dbgs() << "      Analyzing call of " << Callee->getName()
                           << "... (caller:" << Caller->getName() << ")\n");
 
   CallAnalyzer CA(CalleeTTI, GetAssumptionCache, GetBFI, PSI, ORE, *Callee, CS,
                   Params);
-  bool ShouldInline = CA.analyzeCall(CS);
+  InlineResult ShouldInline = CA.analyzeCall(CS);
 
   LLVM_DEBUG(CA.dump());
 
   // Check if there was a reason to force inlining or no inlining.
   if (!ShouldInline && CA.getCost() < CA.getThreshold())
-    return InlineCost::getNever();
+    return InlineCost::getNever(ShouldInline.message);
   if (ShouldInline && CA.getCost() >= CA.getThreshold())
-    return InlineCost::getAlways();
+    return InlineCost::getAlways("empty function");
 
   return llvm::InlineCost::get(CA.getCost(), CA.getThreshold());
 }
 
 bool llvm::isInlineViable(Function &F) {
   bool ReturnsTwice = F.hasFnAttribute(Attribute::ReturnsTwice);
   for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) {
     // Disallow inlining of functions which contain indirect branches or

lib/Target/AMDGPU/AMDGPUInline.cpp

static bool isWrapperOnlyCall(CallSite CS) {
   return false;
 }
 
 InlineCost AMDGPUInliner::getInlineCost(CallSite CS) {
   Function *Callee = CS.getCalledFunction();
   Function *Caller = CS.getCaller();
   TargetTransformInfo &TTI = TTIWP->getTTI(*Callee);
 
-  if (!Callee || Callee->isDeclaration() || CS.isNoInline() ||
-      !TTI.areInlineCompatible(Caller, Callee))
-    return llvm::InlineCost::getNever();
+  if (!Callee || Callee->isDeclaration())
+    return llvm::InlineCost::getNever("undefined callee");
+
+  if (CS.isNoInline())
+    return llvm::InlineCost::getNever("noinline");
+
+  if (!TTI.areInlineCompatible(Caller, Callee))
+    return llvm::InlineCost::getNever("incompatible");
 
   if (CS.hasFnAttr(Attribute::AlwaysInline)) {
     if (isInlineViable(*Callee))
-      return llvm::InlineCost::getAlways();
-    return llvm::InlineCost::getNever();
+      return llvm::InlineCost::getAlways("alwaysinline viable");
+    return llvm::InlineCost::getNever("alwaysinline unviable");
   }
 
   if (isWrapperOnlyCall(CS))
-    return llvm::InlineCost::getAlways();
+    return llvm::InlineCost::getAlways("wrapper-only call");
 
   InlineParams LocalParams = Params;
   LocalParams.DefaultThreshold = (int)getInlineThreshold(CS);
   bool RemarksEnabled = false;
   const auto &BBs = Caller->getBasicBlockList();
   if (!BBs.empty()) {
     auto DI = OptimizationRemark(DEBUG_TYPE, "", DebugLoc(), &BBs.front());
     if (DI.isEnabled())

lib/Transforms/IPO/AlwaysInliner.cpp

 InlineCost AlwaysInlinerLegacyPass::getInlineCost(CallSite CS) {
   Function *Callee = CS.getCalledFunction();
 
   // Only inline direct calls to functions with always-inline attributes
   // that are viable for inlining. FIXME: We shouldn't even get here for
   // declarations.
   if (Callee && !Callee->isDeclaration() &&
       CS.hasFnAttr(Attribute::AlwaysInline) && isInlineViable(*Callee))
-    return InlineCost::getAlways();
+    return InlineCost::getAlways("always inliner");
 
-  return InlineCost::getNever();
+  return InlineCost::getNever("always inliner");
 }

lib/Transforms/IPO/Inliner.cpp

 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Utils/Cloning.h"
 #include "llvm/Transforms/Utils/ImportedFunctionsInliningStatistics.h"
 #include "llvm/Transforms/Utils/ModuleUtils.h"
 #include <algorithm>
 #include <cassert>
 #include <functional>
+#include <sstream>
 #include <tuple>
 #include <utility>
 #include <vector>
 
 using namespace llvm;
 
 #define DEBUG_TYPE "inline"
 
static bool InlineCallIfPossible(
     ImportedFunctionsInliningStatistics &ImportedFunctionsStats) {
   Function *Callee = CS.getCalledFunction();
   Function *Caller = CS.getCaller();
 
   AAResults &AAR = AARGetter(*Callee);
 
   // Try to inline the function.  Get the list of static allocas that were
   // inlined.
-  if (!InlineFunction(CS, IFI, &AAR, InsertLifetime))
-    return false;
+  InlineResult IR = InlineFunction(CS, IFI, &AAR, InsertLifetime);
+  if (!IR)
+    return IR;
 
   if (InlinerFunctionImportStats != InlinerFunctionImportStatsOpts::No)
     ImportedFunctionsStats.recordInline(*Caller, *Callee);
 
   AttributeFuncs::mergeAttributesForInlining(*Caller, *Callee);
 
   if (!DisableInlinedAllocaMerging)
     mergeInlinedArrayAllocas(Caller, IFI, InlinedArrayAllocas, InlineHistory);
 
-  return true;
+  return IR; // success
 }
 
 /// Return true if inlining of CS can block the caller from being
 /// inlined which is proved to be more beneficial. \p IC is the
 /// estimated inline cost associated with callsite \p CS.
 /// \p TotalSecondaryCost will be set to the estimated cost of inlining the
 /// caller if \p CS is suppressed for inlining.
 static bool
if (callerWillBeRemoved && !Caller->hasOneUse())
     TotalSecondaryCost -= InlineConstants::LastCallToStaticBonus;
 
   if (inliningPreventsSomeOuterInline && TotalSecondaryCost < IC.getCost())
     return true;
 
   return false;
 }
 
+static std::basic_ostream<char> &operator<<(std::basic_ostream<char> &R,
+                                            const ore::NV &Arg) {
+  return R << Arg.Val;
+}
+
+template <class RemarkT>
+RemarkT &operator<<(RemarkT &&R, const InlineCost &IC) {
+  using namespace ore;
+  if (IC.isAlways()) {
+    R << "(cost=always)";
+  } else if (IC.isNever()) {
+    R << "(cost=never)";
+  } else {
+    R << "(cost=" << ore::NV("Cost", IC.getCost())
+      << ", threshold=" << ore::NV("Threshold", IC.getThreshold()) << ")";
+  }
+  if (const char *Reason = IC.getReason())
+    R << ": " << ore::NV("Reason", Reason);
+  return R;
+}
+
+static std::string inlineCostStr(const InlineCost &IC) {
+  std::stringstream Remark;
+  Remark << IC;
+  return Remark.str();
+}
+
 /// Return the cost only if the inliner should attempt to inline at the given
 /// CallSite. If we return the cost, we will emit an optimisation remark later
 /// using that cost, so we won't do so from this function.
 static Optional<InlineCost>
 shouldInline(CallSite CS, function_ref<InlineCost(CallSite CS)> GetInlineCost,
              OptimizationRemarkEmitter &ORE) {
   using namespace ore;
 
   InlineCost IC = GetInlineCost(CS);
   Instruction *Call = CS.getInstruction();
   Function *Callee = CS.getCalledFunction();
   Function *Caller = CS.getCaller();
 
   if (IC.isAlways()) {
-    LLVM_DEBUG(dbgs() << "    Inlining: cost=always"
+    LLVM_DEBUG(dbgs() << "    Inlining " << inlineCostStr(IC)
                       << ", Call: " << *CS.getInstruction() << "\n");
     return IC;
   }
 
   if (IC.isNever()) {
-    LLVM_DEBUG(dbgs() << "    NOT Inlining: cost=never"
+    LLVM_DEBUG(dbgs() << "    NOT Inlining " << inlineCostStr(IC)
                       << ", Call: " << *CS.getInstruction() << "\n");
     ORE.emit([&]() {
       return OptimizationRemarkMissed(DEBUG_TYPE, "NeverInline", Call)
              << NV("Callee", Callee) << " not inlined into "
-             << NV("Caller", Caller)
-             << " because it should never be inlined (cost=never)";
+             << NV("Caller", Caller) << " because it should never be inlined "
+             << IC;
     });
-    return None;
+    return IC;
   }
 
   if (!IC) {
-    LLVM_DEBUG(dbgs() << "    NOT Inlining: cost=" << IC.getCost()
-                      << ", thres=" << IC.getThreshold()
+    LLVM_DEBUG(dbgs() << "    NOT Inlining " << inlineCostStr(IC)
                       << ", Call: " << *CS.getInstruction() << "\n");
     ORE.emit([&]() {
       return OptimizationRemarkMissed(DEBUG_TYPE, "TooCostly", Call)
              << NV("Callee", Callee) << " not inlined into "
-             << NV("Caller", Caller) << " because too costly to inline (cost="
-             << NV("Cost", IC.getCost())
-             << ", threshold=" << NV("Threshold", IC.getThreshold()) << ")";
+             << NV("Caller", Caller) << " because too costly to inline " << IC;
     });
-    return None;
+    return IC;
   }
 
   int TotalSecondaryCost = 0;
   if (shouldBeDeferred(Caller, CS, IC, TotalSecondaryCost, GetInlineCost)) {
     LLVM_DEBUG(dbgs() << "    NOT Inlining: " << *CS.getInstruction()
                       << " Cost = " << IC.getCost()
                       << ", outer Cost = " << TotalSecondaryCost << '\n');
     ORE.emit([&]() {
       return OptimizationRemarkMissed(DEBUG_TYPE, "IncreaseCostInOtherContexts",
                                       Call)
              << "Not inlining. Cost of inlining " << NV("Callee", Callee)
              << " increases the cost of inlining " << NV("Caller", Caller)
              << " in other contexts";
     });
 
     // IC does not bool() to false, so get an InlineCost that will.
     // This will not be inspected to make an error message.
     return None;
   }
 
-  LLVM_DEBUG(dbgs() << "    Inlining: cost=" << IC.getCost()
-                    << ", thres=" << IC.getThreshold()
+  LLVM_DEBUG(dbgs() << "    Inlining " << inlineCostStr(IC)
                     << ", Call: " << *CS.getInstruction() << '\n');
   return IC;
 }
 
 /// Return true if the specified inline history ID
 /// indicates an inline history that includes the specified function.
 static bool InlineHistoryIncludes(
     Function *F, int InlineHistoryID,

 }
 
 bool LegacyInlinerBase::runOnSCC(CallGraphSCC &SCC) {
   if (skipSCC(SCC))
     return false;
   return inlineCalls(SCC);
 }
 
+static void emit_inlined_into(OptimizationRemarkEmitter &ORE, DebugLoc &DLoc,
+                              const BasicBlock *Block, const Function &Callee,
+                              const Function &Caller, const InlineCost &IC) {
+  ORE.emit([&]() {
+    bool AlwaysInline = IC.isAlways();
+    StringRef RemarkName = AlwaysInline ? "AlwaysInline" : "Inlined";
+    return OptimizationRemark(DEBUG_TYPE, RemarkName, DLoc, Block)
+           << ore::NV("Callee", &Callee) << " inlined into "
+           << ore::NV("Caller", &Caller) << " with " << IC;
+  });
+}
+
 static bool
 inlineCallsImpl(CallGraphSCC &SCC, CallGraph &CG,
                 std::function<AssumptionCache &(Function &)> GetAssumptionCache,
                 ProfileSummaryInfo *PSI, TargetLibraryInfo &TLI,
                 bool InsertLifetime,
                 function_ref<InlineCost(CallSite CS)> GetInlineCost,
                 function_ref<AAResults &(Function &)> AARGetter,
                 ImportedFunctionsInliningStatistics &ImportedFunctionsStats) {
for (unsigned CSi = 0; CSi != CallSites.size(); ++CSi) {
       // FIXME for new PM: because of the old PM we currently generate ORE and
       // in turn BFI on demand.  With the new PM, the ORE dependency should
       // just become a regular analysis dependency.
       OptimizationRemarkEmitter ORE(Caller);
 
       Optional<InlineCost> OIC = shouldInline(CS, GetInlineCost, ORE);
       // If the policy determines that we should inline this function,
       // delete the call instead.
-      if (!OIC)
+      if (!OIC || !*OIC) {
         continue;
+      }
 
       // If this call site is dead and it is to a readonly function, we should
       // just delete the call instead of trying to inline it, regardless of
       // size.  This happens because IPSCCP propagates the result out of the
       // call and then we're left with the dead call.
       if (IsTriviallyDead) {
         LLVM_DEBUG(dbgs() << "    -> Deleting dead call: " << *Instr << "\n");
         // Update the call graph by deleting the edge from Callee to Caller.
         CG[Caller]->removeCallEdgeFor(CS);
         Instr->eraseFromParent();
         ++NumCallsDeleted;
       } else {
         // Get DebugLoc to report. CS will be invalid after Inliner.
         DebugLoc DLoc = CS->getDebugLoc();
         BasicBlock *Block = CS.getParent();
 
         // Attempt to inline the function.
         using namespace ore;
 
-        if (!InlineCallIfPossible(CS, InlineInfo, InlinedArrayAllocas,
-                                  InlineHistoryID, InsertLifetime, AARGetter,
-                                  ImportedFunctionsStats)) {
+        InlineResult IR = InlineCallIfPossible(
+            CS, InlineInfo, InlinedArrayAllocas, InlineHistoryID,
+            InsertLifetime, AARGetter, ImportedFunctionsStats);
+        if (!IR) {
           ORE.emit([&]() {
             return OptimizationRemarkMissed(DEBUG_TYPE, "NotInlined", DLoc,
                                             Block)
                    << NV("Callee", Callee) << " will not be inlined into "
-                   << NV("Caller", Caller);
+                   << NV("Caller", Caller) << ": " << NV("Reason", IR.message);
           });
           continue;
         }
         ++NumInlined;
 
-        ORE.emit([&]() {
-          bool AlwaysInline = OIC->isAlways();
-          StringRef RemarkName = AlwaysInline ? "AlwaysInline" : "Inlined";
-          OptimizationRemark R(DEBUG_TYPE, RemarkName, DLoc, Block);
-          R << NV("Callee", Callee) << " inlined into ";
-          R << NV("Caller", Caller);
-          if (AlwaysInline)
-            R << " with cost=always";
-          else {
-            R << " with cost=" << NV("Cost", OIC->getCost());
-            R << " (threshold=" << NV("Threshold", OIC->getThreshold());
-            R << ")";
-          }
-          return R;
-        });
+        emit_inlined_into(ORE, DLoc, Block, *Callee, *Caller, *OIC);
 
         // If inlining this function gave us any new call sites, throw them
         // onto our worklist to process.  They are useful inline candidates.
         if (!InlineInfo.InlinedCalls.empty()) {
           // Create a new inline history entry for this, so that we remember
           // that these new callsites came about due to inlining Callee.
           int NewHistoryID = InlineHistory.size();
           InlineHistory.push_back(std::make_pair(Callee, InlineHistoryID));
for (; i < (int)Calls.size() && Calls[i].first.getCaller() == &F; ++i) {
         LLVM_DEBUG(dbgs() << "Skipping inlining internal SCC edge from a node "
                              "previously split out of this SCC by inlining: "
                           << F.getName() << " -> " << Callee.getName() << "\n");
         continue;
       }
 
       Optional<InlineCost> OIC = shouldInline(CS, GetInlineCost, ORE);
       // Check whether we want to inline this callsite.
-      if (!OIC)
+      if (!OIC || !*OIC)
         continue;
 
       // Setup the data structure used to plumb customization into the
       // `InlineFunction` routine.
       InlineFunctionInfo IFI(
           /*cg=*/nullptr, &GetAssumptionCache, PSI,
           &FAM.getResult<BlockFrequencyAnalysis>(*(CS.getCaller())),
           &FAM.getResult<BlockFrequencyAnalysis>(Callee));
 
       // Get DebugLoc to report. CS will be invalid after Inliner.
       DebugLoc DLoc = CS->getDebugLoc();
       BasicBlock *Block = CS.getParent();
 
       using namespace ore;
 
-      if (!InlineFunction(CS, IFI)) {
+      InlineResult IR = InlineFunction(CS, IFI);
+      if (!IR) {
         ORE.emit([&]() {
           return OptimizationRemarkMissed(DEBUG_TYPE, "NotInlined", DLoc, Block)
                  << NV("Callee", &Callee) << " will not be inlined into "
-                 << NV("Caller", &F);
+                 << NV("Caller", &F) << ": " << NV("Reason", IR.message);
         });
         continue;
       }
       DidInline = true;
       InlinedCallees.insert(&Callee);
 
-      ORE.emit([&]() {
-        bool AlwaysInline = OIC->isAlways();
-        StringRef RemarkName = AlwaysInline ? "AlwaysInline" : "Inlined";
-        OptimizationRemark R(DEBUG_TYPE, RemarkName, DLoc, Block);
-        R << NV("Callee", &Callee) << " inlined into ";
-        R << NV("Caller", &F);
-        if (AlwaysInline)
-          R << " with cost=always";
-        else {
-          R << " with cost=" << NV("Cost", OIC->getCost());
-          R << " (threshold=" << NV("Threshold", OIC->getThreshold());
-          R << ")";
-        }
-        return R;
-      });
+      emit_inlined_into(ORE, DLoc, Block, Callee, F, *OIC);
 
       // Add any new callsites to defined functions to the worklist.
       if (!IFI.InlinedCallSites.empty()) {
         int NewHistoryID = InlineHistory.size();
         InlineHistory.push_back({&Callee, InlineHistoryID});
         for (CallSite &CS : reverse(IFI.InlinedCallSites))
           if (Function *NewCallee = CS.getCalledFunction())
             if (!NewCallee->isDeclaration())

lib/Transforms/Utils/InlineFunction.cpp

EnableNoAliasConversion("enable-noalias-to-md-conversion", cl::init(true),
   cl::Hidden,
   cl::desc("Convert noalias attributes to metadata during inlining."));
 
 static cl::opt<bool>
 PreserveAlignmentAssumptions("preserve-alignment-assumptions-during-inlining",
   cl::init(true), cl::Hidden,
   cl::desc("Convert align attributes to assumptions during inlining."));
 
-bool llvm::InlineFunction(CallInst *CI, InlineFunctionInfo &IFI,
-                          AAResults *CalleeAAR, bool InsertLifetime) {
+llvm::InlineResult llvm::InlineFunction(CallInst *CI, InlineFunctionInfo &IFI,
+                                        AAResults *CalleeAAR,
+                                        bool InsertLifetime) {
   return InlineFunction(CallSite(CI), IFI, CalleeAAR, InsertLifetime);
 }
 
-bool llvm::InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI,
-                          AAResults *CalleeAAR, bool InsertLifetime) {
+llvm::InlineResult llvm::InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI,
+                                        AAResults *CalleeAAR,
+                                        bool InsertLifetime) {
   return InlineFunction(CallSite(II), IFI, CalleeAAR, InsertLifetime);
 }
 
 namespace {
 
   /// A class for recording information about inlining a landing pad.
   class LandingPadInliningInfo {
     /// Destination of the invoke's unwind.
else
     CalleeCount.setCount(CalleeCount.getCount() - CallCount.getValue());
   Callee->setEntryCount(CalleeCount);
 }
 
 /// This function inlines the called function into the basic block of the
 /// caller. This returns false if it is not possible to inline this call.
 /// The program is still in a well defined state if this occurs though.
 ///
-/// Note that this only does one level of inlining.  For example, if the
-/// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
-/// exists in the instruction stream.  Similarly this will inline a recursive
-/// function by one level.
-bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
-                          AAResults *CalleeAAR, bool InsertLifetime,
+/// Note that this only does one level of inlining.  For example, if the
+/// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
+/// exists in the instruction stream.  Similarly this will inline a recursive
+/// function by one level.
+llvm::InlineResult llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
+                                        AAResults *CalleeAAR,
+                                        bool InsertLifetime,
                                         Function *ForwardVarArgsTo) {
   Instruction *TheCall = CS.getInstruction();
   assert(TheCall->getParent() && TheCall->getFunction()
          && "Instruction not in function!");
 
   // If IFI has any state in it, zap it before we fill it in.
   IFI.reset();
-
+
   Function *CalledFunc = CS.getCalledFunction();
   if (!CalledFunc ||               // Can't inline external function or indirect
       CalledFunc->isDeclaration()) // call!
-    return false;
+    return "external or indirect";
 
   // The inliner does not know how to inline through calls with operand bundles
   // in general ...
   if (CS.hasOperandBundles()) {
     for (int i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
       uint32_t Tag = CS.getOperandBundleAt(i).getTagID();
       // ... but it knows how to inline through "deopt" operand bundles ...
       if (Tag == LLVMContext::OB_deopt)
         continue;
-      // ... and "funclet" operand bundles.
+      // ... and "funclet" operand bundles.
       if (Tag == LLVMContext::OB_funclet)
         continue;
 
-      return false;
+      return "unsupported operand bundle";
     }
   }
 
   // If the call to the callee cannot throw, set the 'nounwind' flag on any
   // calls that we inline.
   bool MarkNoUnwind = CS.doesNotThrow();
 
   BasicBlock *OrigBB = TheCall->getParent();
   Function *Caller = OrigBB->getParent();
 
   // GC poses two hazards to inlining, which only occur when the callee has GC:
   //  1. If the caller has no GC, then the callee's GC must be propagated to the
   //     caller.
   //  2. If the caller has a differing GC, it is invalid to inline.
-  if (CalledFunc->hasGC()) {
+  if (CalledFunc->hasGC()) {
     if (!Caller->hasGC())
       Caller->setGC(CalledFunc->getGC());
     else if (CalledFunc->getGC() != Caller->getGC())
-      return false;
+      return "incompatible GC";
   }
 
   // Get the personality function from the callee if it contains a landing pad.
   Constant *CalledPersonality =
       CalledFunc->hasPersonalityFn()
           ? CalledFunc->getPersonalityFn()->stripPointerCasts()
           : nullptr;
 
   // Find the personality function used by the landing pads of the caller. If it
   // exists, then check to see that it matches the personality function used in
   // the callee.
   Constant *CallerPersonality =
       Caller->hasPersonalityFn()
           ? Caller->getPersonalityFn()->stripPointerCasts()
           : nullptr;
   if (CalledPersonality) {
     if (!CallerPersonality)
       Caller->setPersonalityFn(CalledPersonality);
     // If the personality functions match, then we can perform the
-    // inlining. Otherwise, we can't inline.
+    // inlining. Otherwise, we can't inline.
     // TODO: This isn't 100% true. Some personality functions are proper
     //       supersets of others and can be used in place of the other.
     else if (CalledPersonality != CallerPersonality)
-      return false;
+      return "incompatible personality";
   }
 
   // We need to figure out which funclet the callsite was in so that we may
   // properly nest the callee.
   Instruction *CallSiteEHPad = nullptr;
   if (CallerPersonality) {
     EHPersonality Personality = classifyEHPersonality(CallerPersonality);
     if (isScopedEHPersonality(Personality)) {
       Optional<OperandBundleUse> ParentFunclet =
           CS.getOperandBundle(LLVMContext::OB_funclet);
       if (ParentFunclet)
         CallSiteEHPad = cast<FuncletPadInst>(ParentFunclet->Inputs.front());
 
       // OK, the inlining site is legal.  What about the target function?
 
       if (CallSiteEHPad) {
         if (Personality == EHPersonality::MSVC_CXX) {
           // The MSVC personality cannot tolerate catches getting inlined into
           // cleanup funclets.
           if (isa<CleanupPadInst>(CallSiteEHPad)) {
-            // Ok, the call site is within a cleanuppad.  Let's check the callee
+            // Ok, the call site is within a cleanuppad.  Let's check the callee
             // for catchpads.
             for (const BasicBlock &CalledBB : *CalledFunc) {
               if (isa<CatchSwitchInst>(CalledBB.getFirstNonPHI()))
-                return false;
+                return "catch in cleanup funclet";
             }
           }
         } else if (isAsynchronousEHPersonality(Personality)) {
-          // SEH is even less tolerant, there may not be any sort of exceptional
+          // SEH is even less tolerant, there may not be any sort of exceptional
           // funclet in the callee.
           for (const BasicBlock &CalledBB : *CalledFunc) {
             if (CalledBB.isEHPad())
-              return false;
+              return "SEH in cleanup funclet";
           }
         }
       }
     }
   }
 
   // Determine if we are dealing with a call in an EHPad which does not unwind
   // to caller.

test/LTO/Resolution/X86/diagnostic-handler-remarks-with-hotness.ll

 ; YAML-NEXT: Pass:            inline
 ; YAML-NEXT: Name:            Inlined
 ; YAML-NEXT: Function:        main
 ; YAML-NEXT: Hotness:         300
 ; YAML-NEXT: Args:
 ; YAML-NEXT:   - Callee:          tinkywinky
 ; YAML-NEXT:   - String:          ' inlined into '
 ; YAML-NEXT:   - Caller:          main
-; YAML-NEXT:   - String:          ' with cost='
+; YAML-NEXT:   - String:          ' with '
+; YAML-NEXT:   - String:          '(cost='
 ; YAML-NEXT:   - Cost:            '-15000'
-; YAML-NEXT:   - String:          ' (threshold='
+; YAML-NEXT:   - String:          ', threshold='
 ; YAML-NEXT:   - Threshold:       '337'
 ; YAML-NEXT:   - String:          ')'
 ; YAML-NEXT: ...
 
-; CHECK: tinkywinky inlined into main with cost=-15000 (threshold=337) (hotness: 300)
+; CHECK: tinkywinky inlined into main with (cost=-15000, threshold=337) (hotness: 300)
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-scei-ps4"
 
 declare i32 @patatino()
 
 define i32 @tinkywinky() {
   %a = call i32 @patatino()

test/LTO/Resolution/X86/diagnostic-handler-remarks.ll

 ; YAML:      --- !Passed
 ; YAML-NEXT: Pass:            inline
 ; YAML-NEXT: Name:            Inlined
 ; YAML-NEXT: Function:        main
 ; YAML-NEXT: Args:
 ; YAML-NEXT:   - Callee:          tinkywinky
 ; YAML-NEXT:   - String:          ' inlined into '
 ; YAML-NEXT:   - Caller:          main
-; YAML-NEXT:   - String:          ' with cost='
+; YAML-NEXT:   - String:          ' with '
+; YAML-NEXT:   - String:          '(cost='
 ; YAML-NEXT:   - Cost:            '-15000'
-; YAML-NEXT:   - String:          ' (threshold='
+; YAML-NEXT:   - String:          ', threshold='
 ; YAML-NEXT:   - Threshold:       '337'
 ; YAML-NEXT:   - String:          ')'
 ; YAML-NEXT: ...
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-scei-ps4"
 
 declare i32 @patatino()

test/LTO/X86/diagnostic-handler-remarks-with-hotness.ll

 ; YAML-NEXT: Pass:            inline
 ; YAML-NEXT: Name:            Inlined
 ; YAML-NEXT: Function:        main
 ; YAML-NEXT: Hotness:         300
 ; YAML-NEXT: Args:
 ; YAML-NEXT:   - Callee:          foo
 ; YAML-NEXT:   - String:          ' inlined into '
 ; YAML-NEXT:   - Caller:          main
-; YAML-NEXT:   - String:          ' with cost='
+; YAML-NEXT:   - String:          ' with '
+; YAML-NEXT:   - String:          '(cost='
 ; YAML-NEXT:   - Cost:            '-15000'
-; YAML-NEXT:   - String:          ' (threshold='
+; YAML-NEXT:   - String:          ', threshold='
 ; YAML-NEXT:   - Threshold:       '337'
 ; YAML-NEXT:   - String:          ')'
 ; YAML-NEXT: ...
 
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-darwin"
 
 declare i32 @bar()

test/LTO/X86/diagnostic-handler-remarks.ll

 ; YAML:      --- !Passed
 ; YAML-NEXT: Pass:            inline
 ; YAML-NEXT: Name:            Inlined
 ; YAML-NEXT: Function:        main
 ; YAML-NEXT: Args:
 ; YAML-NEXT:   - Callee:          foo
 ; YAML-NEXT:   - String:          ' inlined into '
 ; YAML-NEXT:   - Caller:          main
-; YAML-NEXT:   - String:          ' with cost='
+; YAML-NEXT:   - String:          ' with '
+; YAML-NEXT:   - String:          '(cost='
 ; YAML-NEXT:   - Cost:            '-15000'
-; YAML-NEXT:   - String:          ' (threshold='
+; YAML-NEXT:   - String:          ', threshold='
 ; YAML-NEXT:   - Threshold:       '337'
 ; YAML-NEXT:   - String:          ')'
 ; YAML-NEXT: ...
 
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-darwin"
 
 declare i32 @bar()

test/ThinLTO/X86/diagnostic-handler-remarks-with-hotness.ll

 ; YAML1-NEXT: Pass:            inline
 ; YAML1-NEXT: Name:            Inlined
 ; YAML1-NEXT: Function:        main
 ; YAML1-NEXT: Hotness:         50
 ; YAML1-NEXT: Args:
 ; YAML1-NEXT:   - Callee:          foo
 ; YAML1-NEXT:   - String:          ' inlined into '
 ; YAML1-NEXT:   - Caller:          main
-; YAML1-NEXT:   - String:          ' with cost='
+; YAML1-NEXT:   - String:          ' with '
+; YAML1-NEXT:   - String:          '(cost='
 ; YAML1-NEXT:   - Cost:            '-30'
-; YAML1-NEXT:   - String:          ' (threshold='
+; YAML1-NEXT:   - String:          ', threshold='
 ; YAML1-NEXT:   - Threshold:       '337'
 ; YAML1-NEXT:   - String:          ')'
 ; YAML1-NEXT: ...
 
 
 ; Verify that bar is imported and inlined into foo
 ; RUN: cat %t.yaml.thin.1.yaml | FileCheck %s -check-prefix=YAML2
 ; YAML2:      --- !Passed
 ; YAML2-NEXT: Pass:            inline
 ; YAML2-NEXT: Name:            Inlined
 ; YAML2-NEXT: Function:        foo
 ; YAML2-NEXT: Args:
 ; YAML2-NEXT:   - Callee:          bar
 ; YAML2-NEXT:   - String:          ' inlined into '
 ; YAML2-NEXT:   - Caller:          foo
-; YAML2-NEXT:   - String:          ' with cost='
+; YAML2-NEXT:   - String:          ' with '
+; YAML2-NEXT:   - String:          '(cost='
 ; YAML2-NEXT:   - Cost:            '-30'
-; YAML2-NEXT:   - String:          ' (threshold='
+; YAML2-NEXT:   - String:          ', threshold='
 ; YAML2-NEXT:   - Threshold:       '337'
 ; YAML2-NEXT:   - String:          ')'
 ; YAML2-NEXT: ...
 
 
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.11.0"
 

test/ThinLTO/X86/diagnostic-handler-remarks.ll

 ; YAML1:      --- !Passed
 ; YAML1-NEXT: Pass:            inline
 ; YAML1-NEXT: Name:            Inlined
 ; YAML1-NEXT: Function:        main
 ; YAML1-NEXT: Args:
 ; YAML1-NEXT:   - Callee:          foo
 ; YAML1-NEXT:   - String:          ' inlined into '
 ; YAML1-NEXT:   - Caller:          main
-; YAML1-NEXT:   - String:          ' with cost='
+; YAML1-NEXT:   - String:          ' with '
+; YAML1-NEXT:   - String:          '(cost='
 ; YAML1-NEXT:   - Cost:            '-30'
-; YAML1-NEXT:   - String:          ' (threshold='
+; YAML1-NEXT:   - String:          ', threshold='
 ; YAML1-NEXT:   - Threshold:       '337'
 ; YAML1-NEXT:   - String:          ')'
 ; YAML1-NEXT: ...
 
 
 ; Verify that bar is imported and inlined into foo
 ; RUN: cat %t.yaml.thin.1.yaml | FileCheck %s -check-prefix=YAML2
 ; YAML2: --- !Passed
 ; YAML2-NEXT: Pass:            inline
 ; YAML2-NEXT: Name:            Inlined
 ; YAML2-NEXT: Function:        foo
 ; YAML2-NEXT: Args:
 ; YAML2-NEXT:   - Callee:          bar
 ; YAML2-NEXT:   - String:          ' inlined into '
 ; YAML2-NEXT:   - Caller:          foo
-; YAML2-NEXT:   - String:          ' with cost='
+; YAML2-NEXT:   - String:          ' with '
+; YAML2-NEXT:   - String:          '(cost='
 ; YAML2-NEXT:   - Cost:            '-30'
-; YAML2-NEXT:   - String:          ' (threshold='
+; YAML2-NEXT:   - String:          ', threshold='
 ; YAML2-NEXT:   - Threshold:       '337'
 ; YAML2-NEXT:   - String:          ')'
 ; YAML2-NEXT: ...
 
 
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.11.0"
 

test/Transforms/Inline/ARM/inline-fp.ll

 ; RUN: opt -S -inline -mtriple=arm-eabi -pass-remarks=.* -pass-remarks-missed=.* < %s 2>&1 | FileCheck %s -check-prefix=NOFP
 ; RUN: opt -S -inline -mtriple=arm-eabi -mattr=+vfp2 -pass-remarks=.* -pass-remarks-missed=.* < %s 2>&1 | FileCheck %s -check-prefix=FULLFP
 ; RUN: opt -S -inline -mtriple=arm-eabi -mattr=+vfp2,+fp-only-sp -pass-remarks=.* -pass-remarks-missed=.* < %s 2>&1 | FileCheck %s -check-prefix=SINGLEFP
 ; Make sure that soft float implementations are calculated as being more expensive
 ; to the inliner.
 
 ; NOFP-DAG: single not inlined into test_single because too costly to inline (cost=125, threshold=75)
 ; NOFP-DAG: single not inlined into test_single because too costly to inline (cost=125, threshold=75)
-; NOFP-DAG: single_cheap inlined into test_single_cheap with cost=-15 (threshold=75)
-; NOFP-DAG: single_cheap inlined into test_single_cheap with cost=-15015 (threshold=75)
+; NOFP-DAG: single_cheap inlined into test_single_cheap with (cost=-15, threshold=75)
+; NOFP-DAG: single_cheap inlined into test_single_cheap with (cost=-15015, threshold=75)
 ; NOFP-DAG: double not inlined into test_double because too costly to inline (cost=125, threshold=75)
 ; NOFP-DAG: double not inlined into test_double because too costly to inline (cost=125, threshold=75)
 ; NOFP-DAG: single_force_soft not inlined into test_single_force_soft because too costly to inline (cost=125, threshold=75)
 ; NOFP-DAG: single_force_soft not inlined into test_single_force_soft because too costly to inline (cost=125, threshold=75)
 
-; FULLFP-DAG: single inlined into test_single with cost=0 (threshold=75)
-; FULLFP-DAG: single inlined into test_single with cost=-15000 (threshold=75)
-; FULLFP-DAG: single_cheap inlined into test_single_cheap with cost=-15 (threshold=75)
-; FULLFP-DAG: single_cheap inlined into test_single_cheap with cost=-15015 (threshold=75)
-; FULLFP-DAG: double inlined into test_double with cost=0 (threshold=75)
-; FULLFP-DAG: double inlined into test_double with cost=-15000 (threshold=75)
+; FULLFP-DAG: single inlined into test_single with (cost=0, threshold=75)
+; FULLFP-DAG: single inlined into test_single with (cost=-15000, threshold=75)
+; FULLFP-DAG: single_cheap inlined into test_single_cheap with (cost=-15, threshold=75)
+; FULLFP-DAG: single_cheap inlined into test_single_cheap with (cost=-15015, threshold=75)
+; FULLFP-DAG: double inlined into test_double with (cost=0, threshold=75)
+; FULLFP-DAG: double inlined into test_double with (cost=-15000, threshold=75)
 ; FULLFP-DAG: single_force_soft not inlined into test_single_force_soft because too costly to inline (cost=125, threshold=75)
 ; FULLFP-DAG: single_force_soft not inlined into test_single_force_soft because too costly to inline (cost=125, threshold=75)
 
-; SINGLEFP-DAG: single inlined into test_single with cost=0 (threshold=75)
-; SINGLEFP-DAG: single inlined into test_single with cost=-15000 (threshold=75)
-; SINGLEFP-DAG: single_cheap inlined into test_single_cheap with cost=-15 (threshold=75)
-; SINGLEFP-DAG: single_cheap inlined into test_single_cheap with cost=-15015 (threshold=75)
+; SINGLEFP-DAG: single inlined into test_single with (cost=0, threshold=75)
+; SINGLEFP-DAG: single inlined into test_single with (cost=-15000, threshold=75)
+; SINGLEFP-DAG: single_cheap inlined into test_single_cheap with (cost=-15, threshold=75)
+; SINGLEFP-DAG: single_cheap inlined into test_single_cheap with (cost=-15015, threshold=75)
 ; SINGLEFP-DAG: double not inlined into test_double because too costly to inline (cost=125, threshold=75)
 ; SINGLEFP-DAG: double not inlined into test_double because too costly to inline (cost=125, threshold=75)
 ; SINGLEFP-DAG: single_force_soft not inlined into test_single_force_soft because too costly to inline (cost=125, threshold=75)
 ; SINGLEFP-DAG: single_force_soft not inlined into test_single_force_soft because too costly to inline (cost=125, threshold=75)
 
 define i32 @test_single(i32 %a, i8 %b, i32 %c, i8 %d) #0 {
   %call = call float @single(i32 %a, i8 zeroext %b)
   %call2 = call float @single(i32 %c, i8 zeroext %d)

test/Transforms/Inline/optimization-remarks-hotness-threshold.ll

 ; RUN: opt < %s -S -inline -pass-remarks=inline \
 ; RUN:    -pass-remarks-with-hotness 2>&1 | FileCheck %s
 
 ; RUN: opt < %s -S -passes=inline -pass-remarks-output=%t -pass-remarks=inline \
 ; RUN:    -pass-remarks-with-hotness -pass-remarks-hotness-threshold=1 2>&1 | \
 ; RUN:    FileCheck -allow-empty -check-prefix=THRESHOLD %s
 
 ; Check that when any threshold is specified we ignore remarks with no
 ; hotness -- these are blocks that have not been executed during training.
 
 ;  1     int foo() { return 1; }
 ;  2
 ;  3     int bar() {
 ;  4       return foo();
 ;  5     }
 
-; CHECK: remark: /tmp/s.c:4:10: foo inlined into bar with cost={{[0-9\-]+}} (threshold={{[0-9]+}})
+; CHECK: remark: /tmp/s.c:4:10: foo inlined into bar with (cost={{[0-9\-]+}}, threshold={{[0-9]+}})
 ; THRESHOLD-NOT: remark
 
 ; ModuleID = '/tmp/s.c'
 source_filename = "/tmp/s.c"
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.11.0"
 
 ; Function Attrs: nounwind ssp uwtable

test/Transforms/Inline/optimization-remarks-passed-yaml.ll

 ; is the input:
 
 ;  1     int foo() { return 1; }
 ;  2
 ;  3     int bar() {
 ;  4       return foo();
 ;  5     }
 
-; CHECK: remark: /tmp/s.c:4:10: foo inlined into bar with cost={{[0-9\-]+}} (threshold={{[0-9]+}}) (hotness: 30)
+; CHECK: remark: /tmp/s.c:4:10: foo inlined into bar with (cost={{[0-9\-]+}}, threshold={{[0-9]+}}) (hotness: 30)
 
 ; YAML:      --- !Passed
 ; YAML-NEXT: Pass:            inline
 ; YAML-NEXT: Name:            Inlined
 ; YAML-NEXT: DebugLoc:        { File: /tmp/s.c, Line: 4, Column: 10 }
 ; YAML-NEXT: Function:        bar
 ; YAML-NEXT: Hotness:         30
 ; YAML-NEXT: Args:
 ; YAML-NEXT:   - Callee: foo
 ; YAML-NEXT:     DebugLoc:        { File: /tmp/s.c, Line: 1, Column: 0 }
 ; YAML-NEXT:   - String: ' inlined into '
 ; YAML-NEXT:   - Caller: bar
 ; YAML-NEXT:     DebugLoc:        { File: /tmp/s.c, Line: 3, Column: 0 }
-; YAML-NEXT:   - String: ' with cost='
+; YAML-NEXT:   - String: ' with '
+; YAML-NEXT:   - String: '(cost='
 ; YAML-NEXT:   - Cost: '{{[0-9\-]+}}'
-; YAML-NEXT:   - String: ' (threshold='
+; YAML-NEXT:   - String: ', threshold='
 ; YAML-NEXT:   - Threshold: '{{[0-9]+}}'
 ; YAML-NEXT:   - String: ')'
 ; YAML-NEXT: ...
 
 ; ModuleID = '/tmp/s.c'
 source_filename = "/tmp/s.c"
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.11.0"

test/Transforms/Inline/optimization-remarks-with-hotness.ll

 ; RUN: opt < %s -inline -pass-remarks=inline -pass-remarks-missed=inline \
 ; RUN:     -pass-remarks-analysis=inline -pass-remarks-with-hotness -S 2>&1 \
 ; RUN:     | FileCheck %s
 ; RUN: opt < %s -passes=inline -pass-remarks=inline -pass-remarks-missed=inline \
 ; RUN:     -pass-remarks-analysis=inline -pass-remarks-with-hotness -S 2>&1 \
 ; RUN:     | FileCheck %s
 
-; CHECK: foo inlined into bar with cost=always (hotness: 30)
-; CHECK: foz not inlined into bar because it should never be inlined (cost=never) (hotness: 30)
+; CHECK: foo inlined into bar with (cost=always): always inline attribute (hotness: 30)
+; CHECK: foz not inlined into bar because it should never be inlined (cost=never): noinline function attribute (hotness: 30)
 
 ; Function Attrs: alwaysinline nounwind uwtable
 define i32 @foo() #0 !prof !1 {
 entry:
   ret i32 4
 }
 
 ; Function Attrs: noinline nounwind uwtable

test/Transforms/Inline/optimization-remarks.ll

 ; RUN: opt < %s -inline -pass-remarks=inline -pass-remarks-missed=inline \
 ; RUN:       -pass-remarks-analysis=inline -S 2>&1 | \
 ; RUN:       FileCheck -check-prefix=CHECK -check-prefix=NO_HOTNESS %s
 ; RUN: opt < %s -inline -pass-remarks=inline -pass-remarks-missed=inline \
 ; RUN:       -pass-remarks-analysis=inline -pass-remarks-with-hotness -S 2>&1 | \
 ; RUN:       FileCheck -check-prefix=CHECK -check-prefix=HOTNESS %s
 
 ; RUN: opt < %s -passes=inline -pass-remarks=inline -pass-remarks-missed=inline \
 ; RUN:       -pass-remarks-analysis=inline -S 2>&1 | \
 ; RUN:       FileCheck -check-prefix=CHECK -check-prefix=NO_HOTNESS %s
 ; RUN: opt < %s -passes=inline -pass-remarks=inline -pass-remarks-missed=inline \
 ; RUN:       -pass-remarks-analysis=inline -pass-remarks-with-hotness -S 2>&1 | \
 ; RUN:       FileCheck -check-prefix=CHECK -check-prefix=HOTNESS %s
 
 ; HOTNESS: fox will not be inlined into bar because its definition is unavailable
 ; NO_HOTNESS-NOT: fox will not be inlined into bar because its definition is unavailable
-; CHECK: foo inlined into bar with cost=always
-; CHECK: foz not inlined into bar because it should never be inlined (cost=never)
+; CHECK: foo inlined into bar with (cost=always): always inline attribute
+; CHECK: foz not inlined into bar because it should never be inlined (cost=never): noinline function attribute
 
 ; Function Attrs: alwaysinline nounwind uwtable
 define i32 @foo(i32 %x, i32 %y) #0 !prof !1 {
 entry:
   %x.addr = alloca i32, align 4
   %y.addr = alloca i32, align 4
   store i32 %x, i32* %x.addr, align 4
   store i32 %y, i32* %y.addr, align 4

test/tools/gold/X86/opt-remarks.ll

 ; YAML-NEXT: --- !Passed
 ; YAML-NEXT: Pass:            inline
 ; YAML-NEXT: Name:            Inlined
 ; YAML-NEXT: Function:        _start
 ; YAML-NEXT: Args:
 ; YAML-NEXT:   - Callee:          f
 ; YAML-NEXT:   - String:          ' inlined into '
 ; YAML-NEXT:   - Caller:          _start
-; YAML-NEXT:   - String:          ' with cost='
+; YAML-NEXT:   - String:          ' with '
+; YAML-NEXT:   - String:          'cost='
 ; YAML-NEXT:   - Cost:            '0'
 ; YAML-NEXT:   - String:          ' (threshold='
 ; YAML-NEXT:   - Threshold:       '337'
 ; YAML-NEXT:   - String:          ')'
 ; YAML-NEXT: ...
 
 ; YAML-HOT: ...
 ; YAML-HOT: --- !Passed
 ; YAML-HOT: Pass:            inline
 ; YAML-HOT-NEXT: Name:            Inlined
 ; YAML-HOT-NEXT: Function:        _start
 ; YAML-HOT-NEXT: Hotness:         300
 ; YAML-HOT-NEXT: Args:
 ; YAML-HOT-NEXT:   - Callee:          f
 ; YAML-HOT-NEXT:   - String:          ' inlined into '
 ; YAML-HOT-NEXT:   - Caller:          _start
-; YAML-HOT-NEXT:   - String:          ' with cost='
+; YAML-HOT-NEXT:   - String:          ' with'
+; YAML-HOT-NEXT:   - String:          'cost='
 ; YAML-HOT-NEXT:   - Cost:            '0'
 ; YAML-HOT-NEXT:   - String:          ' (threshold='
 ; YAML-HOT-NEXT:   - Threshold:       '337'
 ; YAML-HOT-NEXT:   - String:          ')'
 ; YAML-HOT-NEXT: ...
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"