int Threshold;
int Cost;
- const bool AlwaysInline;
bool IsCallerRecursive;
bool IsRecursiveCall;
public:
CallAnalyzer(const DataLayout *TD, Function &Callee, int Threshold)
: TD(TD), F(Callee), Threshold(Threshold), Cost(0),
- AlwaysInline(F.getFnAttributes().hasAttribute(Attributes::AlwaysInline)),
IsCallerRecursive(false), IsRecursiveCall(false),
ExposesReturnsTwice(false), HasDynamicAlloca(false), AllocatedSize(0),
NumInstructions(0), NumVectorInstructions(0),
int getThreshold() { return Threshold; }
int getCost() { return Cost; }
- bool isAlwaysInline() { return AlwaysInline; }
// Keep a bunch of stats about the cost savings found so we can print them
// out when debugging.
Ty->getPrimitiveSizeInBits());
}
- // We will happily inline static alloca instructions or dynamic alloca
- // instructions in always-inline situations.
- if (AlwaysInline || I.isStaticAlloca())
+ // We will happily inline static alloca instructions.
+ if (I.isStaticAlloca())
return Base::visitAlloca(I);
// FIXME: This is overly conservative. Dynamic allocas are inefficient for
// Check if we've past the threshold so we don't spin in huge basic
// blocks that will never inline.
- if (!AlwaysInline && Cost > (Threshold + VectorBonus))
+ if (Cost > (Threshold + VectorBonus))
return false;
}
int SingleBBBonus = Threshold / 2;
Threshold += SingleBBBonus;
- // Unless we are always-inlining, perform some tweaks to the cost and
- // threshold based on the direct callsite information.
- if (!AlwaysInline) {
- // 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.
- assert(NumInstructions == 0);
- assert(NumVectorInstructions == 0);
- FiftyPercentVectorBonus = Threshold;
- TenPercentVectorBonus = Threshold / 2;
-
- // Give out bonuses per argument, as the instructions setting them up will
- // be gone after inlining.
- for (unsigned I = 0, E = CS.arg_size(); I != E; ++I) {
- if (TD && CS.isByValArgument(I)) {
- // We approximate the number of loads and stores needed by dividing the
- // size of the byval type by the target's pointer size.
- PointerType *PTy = cast<PointerType>(CS.getArgument(I)->getType());
- unsigned TypeSize = TD->getTypeSizeInBits(PTy->getElementType());
- unsigned PointerSize = TD->getPointerSizeInBits();
- // Ceiling division.
- unsigned NumStores = (TypeSize + PointerSize - 1) / PointerSize;
-
- // If it generates more than 8 stores it is likely to be expanded as an
- // inline memcpy so we take that as an upper bound. Otherwise we assume
- // one load and one store per word copied.
- // FIXME: The maxStoresPerMemcpy setting from the target should be used
- // here instead of a magic number of 8, but it's not available via
- // DataLayout.
- NumStores = std::min(NumStores, 8U);
-
- Cost -= 2 * NumStores * InlineConstants::InstrCost;
- } else {
- // For non-byval arguments subtract off one instruction per call
- // argument.
- Cost -= InlineConstants::InstrCost;
- }
+ // 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.
+ assert(NumInstructions == 0);
+ assert(NumVectorInstructions == 0);
+ FiftyPercentVectorBonus = Threshold;
+ TenPercentVectorBonus = Threshold / 2;
+
+ // Give out bonuses per argument, as the instructions setting them up will
+ // be gone after inlining.
+ for (unsigned I = 0, E = CS.arg_size(); I != E; ++I) {
+ if (TD && CS.isByValArgument(I)) {
+ // We approximate the number of loads and stores needed by dividing the
+ // size of the byval type by the target's pointer size.
+ PointerType *PTy = cast<PointerType>(CS.getArgument(I)->getType());
+ unsigned TypeSize = TD->getTypeSizeInBits(PTy->getElementType());
+ unsigned PointerSize = TD->getPointerSizeInBits();
+ // Ceiling division.
+ unsigned NumStores = (TypeSize + PointerSize - 1) / PointerSize;
+
+ // If it generates more than 8 stores it is likely to be expanded as an
+ // inline memcpy so we take that as an upper bound. Otherwise we assume
+ // one load and one store per word copied.
+ // FIXME: The maxStoresPerMemcpy setting from the target should be used
+ // here instead of a magic number of 8, but it's not available via
+ // DataLayout.
+ NumStores = std::min(NumStores, 8U);
+
+ Cost -= 2 * NumStores * InlineConstants::InstrCost;
+ } else {
+ // For non-byval arguments subtract off one instruction per call
+ // argument.
+ Cost -= InlineConstants::InstrCost;
}
+ }
- // If there is only one call of the function, and it has internal linkage,
- // the cost of inlining it drops dramatically.
- if (F.hasLocalLinkage() && F.hasOneUse() && &F == CS.getCalledFunction())
- Cost += InlineConstants::LastCallToStaticBonus;
-
- // If the instruction after the call, or if the normal destination of the
- // invoke is an unreachable instruction, the function is noreturn. As such,
- // there is little point in inlining this unless there is literally zero
- // cost.
- Instruction *Instr = CS.getInstruction();
- if (InvokeInst *II = dyn_cast<InvokeInst>(Instr)) {
- if (isa<UnreachableInst>(II->getNormalDest()->begin()))
- Threshold = 1;
- } else if (isa<UnreachableInst>(++BasicBlock::iterator(Instr)))
+ // If there is only one call of the function, and it has internal linkage,
+ // the cost of inlining it drops dramatically.
+ if (F.hasLocalLinkage() && F.hasOneUse() && &F == CS.getCalledFunction())
+ Cost += InlineConstants::LastCallToStaticBonus;
+
+ // If the instruction after the call, or if the normal destination of the
+ // invoke is an unreachable instruction, the function is noreturn. As such,
+ // there is little point in inlining this unless there is literally zero
+ // cost.
+ Instruction *Instr = CS.getInstruction();
+ if (InvokeInst *II = dyn_cast<InvokeInst>(Instr)) {
+ if (isa<UnreachableInst>(II->getNormalDest()->begin()))
Threshold = 1;
+ } else if (isa<UnreachableInst>(++BasicBlock::iterator(Instr)))
+ Threshold = 1;
- // If this function uses the coldcc calling convention, prefer not to inline
- // it.
- if (F.getCallingConv() == CallingConv::Cold)
- Cost += InlineConstants::ColdccPenalty;
+ // 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)
- return false;
- }
+ // Check if we're done. This can happen due to bonuses and penalties.
+ if (Cost > Threshold)
+ return false;
if (F.empty())
return true;
for (unsigned Idx = 0; Idx != BBWorklist.size(); ++Idx) {
// Bail out the moment we cross the threshold. This means we'll under-count
// the cost, but only when undercounting doesn't matter.
- if (!AlwaysInline && Cost > (Threshold + VectorBonus))
+ if (Cost > (Threshold + VectorBonus))
break;
BasicBlock *BB = BBWorklist[Idx];
Threshold += VectorBonus;
- return AlwaysInline || Cost < Threshold;
+ return Cost < Threshold;
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS, Function *Callee,
int Threshold) {
+ // Cannot inline indirect calls.
+ if (!Callee)
+ return llvm::InlineCost::getNever();
+
+ // Calls to functions with always-inline attributes should be inlined
+ // whenever possible.
+ if (Callee->getFnAttributes().hasAttribute(Attributes::AlwaysInline)) {
+ if (isInlineViable(*Callee))
+ return llvm::InlineCost::getAlways();
+ return llvm::InlineCost::getNever();
+ }
+
// Don't inline functions which can be redefined at link-time to mean
// something else. Don't inline functions marked noinline or call sites
// marked noinline.
- if (!Callee || Callee->mayBeOverridden() ||
+ if (Callee->mayBeOverridden() ||
Callee->getFnAttributes().hasAttribute(Attributes::NoInline) ||
CS.isNoInline())
return llvm::InlineCost::getNever();
// Check if there was a reason to force inlining or no inlining.
if (!ShouldInline && CA.getCost() < CA.getThreshold())
return InlineCost::getNever();
- if (ShouldInline && (CA.isAlwaysInline() ||
- CA.getCost() >= CA.getThreshold()))
+ if (ShouldInline && CA.getCost() >= CA.getThreshold())
return InlineCost::getAlways();
return llvm::InlineCost::get(CA.getCost(), CA.getThreshold());
}
+
+bool InlineCostAnalyzer::isInlineViable(Function &F) {
+ bool ReturnsTwice =F.getFnAttributes().hasAttribute(Attributes::ReturnsTwice);
+ for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) {
+ // Disallow inlining of functions which contain an indirect branch.
+ if (isa<IndirectBrInst>(BI->getTerminator()))
+ return false;
+
+ for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE;
+ ++II) {
+ CallSite CS(II);
+ if (!CS)
+ continue;
+
+ // Disallow recursive calls.
+ if (&F == CS.getCalledFunction())
+ return false;
+
+ // Disallow calls which expose returns-twice to a function not previously
+ // attributed as such.
+ if (!ReturnsTwice && CS.isCall() &&
+ cast<CallInst>(CS.getInstruction())->canReturnTwice())
+ return false;
+ }
+ }
+
+ return true;
+}
// AlwaysInliner only inlines functions that are mark as "always inline".
class AlwaysInliner : public Inliner {
+ InlineCostAnalyzer CA;
public:
// Use extremely low threshold.
AlwaysInliner() : Inliner(ID, -2000000000, /*InsertLifetime*/true) {
return new AlwaysInliner(InsertLifetime);
}
-/// \brief Minimal filter to detect invalid constructs for inlining.
-static bool isInlineViable(Function &F) {
- bool ReturnsTwice =F.getFnAttributes().hasAttribute(Attributes::ReturnsTwice);
- for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) {
- // Disallow inlining of functions which contain an indirect branch.
- if (isa<IndirectBrInst>(BI->getTerminator()))
- return false;
-
- for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE;
- ++II) {
- CallSite CS(II);
- if (!CS)
- continue;
-
- // Disallow recursive calls.
- if (&F == CS.getCalledFunction())
- return false;
-
- // Disallow calls which expose returns-twice to a function not previously
- // attributed as such.
- if (!ReturnsTwice && CS.isCall() &&
- cast<CallInst>(CS.getInstruction())->canReturnTwice())
- return false;
- }
- }
-
- return true;
-}
-
/// \brief Get the inline cost for the always-inliner.
///
/// The always inliner *only* handles functions which are marked with the
/// likely not worth it in practice.
InlineCost AlwaysInliner::getInlineCost(CallSite CS) {
Function *Callee = CS.getCalledFunction();
- // We assume indirect calls aren't calling an always-inline function.
- if (!Callee) return InlineCost::getNever();
-
- // We can't inline calls to external functions.
- // FIXME: We shouldn't even get here.
- if (Callee->isDeclaration()) return InlineCost::getNever();
-
- // Return never for anything not marked as always inline.
- if (!Callee->getFnAttributes().hasAttribute(Attributes::AlwaysInline))
- return InlineCost::getNever();
- // Do some minimal analysis to preclude non-viable functions.
- if (!isInlineViable(*Callee))
- return InlineCost::getNever();
+ // 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() &&
+ Callee->getFnAttributes().hasAttribute(Attributes::AlwaysInline) &&
+ CA.isInlineViable(*Callee))
+ return InlineCost::getAlways();
- // Otherwise, force inlining.
- return InlineCost::getAlways();
+ return InlineCost::getNever();
}
// doInitialization - Initializes the vector of functions that have not
// been annotated with the "always inline" attribute.
bool AlwaysInliner::doInitialization(CallGraph &CG) {
+ CA.setDataLayout(getAnalysisIfAvailable<DataLayout>());
return false;
}
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