forked from OSchip/llvm-project
1669 lines
63 KiB
C++
1669 lines
63 KiB
C++
//===- InlineCost.cpp - Cost analysis for inliner -------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements inline cost analysis.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Analysis/InlineCost.h"
|
|
#include "llvm/ADT/STLExtras.h"
|
|
#include "llvm/ADT/SetVector.h"
|
|
#include "llvm/ADT/SmallPtrSet.h"
|
|
#include "llvm/ADT/SmallVector.h"
|
|
#include "llvm/ADT/Statistic.h"
|
|
#include "llvm/Analysis/AssumptionCache.h"
|
|
#include "llvm/Analysis/BlockFrequencyInfo.h"
|
|
#include "llvm/Analysis/CodeMetrics.h"
|
|
#include "llvm/Analysis/ConstantFolding.h"
|
|
#include "llvm/Analysis/InstructionSimplify.h"
|
|
#include "llvm/Analysis/ProfileSummaryInfo.h"
|
|
#include "llvm/Analysis/TargetTransformInfo.h"
|
|
#include "llvm/IR/CallSite.h"
|
|
#include "llvm/IR/CallingConv.h"
|
|
#include "llvm/IR/DataLayout.h"
|
|
#include "llvm/IR/GetElementPtrTypeIterator.h"
|
|
#include "llvm/IR/GlobalAlias.h"
|
|
#include "llvm/IR/InstVisitor.h"
|
|
#include "llvm/IR/IntrinsicInst.h"
|
|
#include "llvm/IR/Operator.h"
|
|
#include "llvm/Support/Debug.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
|
|
using namespace llvm;
|
|
|
|
#define DEBUG_TYPE "inline-cost"
|
|
|
|
STATISTIC(NumCallsAnalyzed, "Number of call sites analyzed");
|
|
|
|
static cl::opt<int> InlineThreshold(
|
|
"inline-threshold", cl::Hidden, cl::init(225), cl::ZeroOrMore,
|
|
cl::desc("Control the amount of inlining to perform (default = 225)"));
|
|
|
|
static cl::opt<int> HintThreshold(
|
|
"inlinehint-threshold", cl::Hidden, cl::init(325),
|
|
cl::desc("Threshold for inlining functions with inline hint"));
|
|
|
|
static cl::opt<int>
|
|
ColdCallSiteThreshold("inline-cold-callsite-threshold", cl::Hidden,
|
|
cl::init(45),
|
|
cl::desc("Threshold for inlining cold callsites"));
|
|
|
|
static cl::opt<bool>
|
|
EnableGenericSwitchCost("inline-generic-switch-cost", cl::Hidden,
|
|
cl::init(false),
|
|
cl::desc("Enable generic switch cost model"));
|
|
|
|
// We introduce this threshold to help performance of instrumentation based
|
|
// PGO before we actually hook up inliner with analysis passes such as BPI and
|
|
// BFI.
|
|
static cl::opt<int> ColdThreshold(
|
|
"inlinecold-threshold", cl::Hidden, cl::init(225),
|
|
cl::desc("Threshold for inlining functions with cold attribute"));
|
|
|
|
static cl::opt<int>
|
|
HotCallSiteThreshold("hot-callsite-threshold", cl::Hidden, cl::init(3000),
|
|
cl::ZeroOrMore,
|
|
cl::desc("Threshold for hot callsites "));
|
|
|
|
namespace {
|
|
|
|
class CallAnalyzer : public InstVisitor<CallAnalyzer, bool> {
|
|
typedef InstVisitor<CallAnalyzer, bool> Base;
|
|
friend class InstVisitor<CallAnalyzer, bool>;
|
|
|
|
/// The TargetTransformInfo available for this compilation.
|
|
const TargetTransformInfo &TTI;
|
|
|
|
/// Getter for the cache of @llvm.assume intrinsics.
|
|
std::function<AssumptionCache &(Function &)> &GetAssumptionCache;
|
|
|
|
/// Getter for BlockFrequencyInfo
|
|
Optional<function_ref<BlockFrequencyInfo &(Function &)>> &GetBFI;
|
|
|
|
/// Profile summary information.
|
|
ProfileSummaryInfo *PSI;
|
|
|
|
/// The called function.
|
|
Function &F;
|
|
|
|
// Cache the DataLayout since we use it a lot.
|
|
const DataLayout &DL;
|
|
|
|
/// The candidate callsite being analyzed. Please do not use this to do
|
|
/// analysis in the caller function; we want the inline cost query to be
|
|
/// easily cacheable. Instead, use the cover function paramHasAttr.
|
|
CallSite CandidateCS;
|
|
|
|
/// Tunable parameters that control the analysis.
|
|
const InlineParams &Params;
|
|
|
|
int Threshold;
|
|
int Cost;
|
|
|
|
bool IsCallerRecursive;
|
|
bool IsRecursiveCall;
|
|
bool ExposesReturnsTwice;
|
|
bool HasDynamicAlloca;
|
|
bool ContainsNoDuplicateCall;
|
|
bool HasReturn;
|
|
bool HasIndirectBr;
|
|
bool HasFrameEscape;
|
|
|
|
/// Number of bytes allocated statically by the callee.
|
|
uint64_t AllocatedSize;
|
|
unsigned NumInstructions, NumVectorInstructions;
|
|
int FiftyPercentVectorBonus, TenPercentVectorBonus;
|
|
int VectorBonus;
|
|
|
|
/// While we walk the potentially-inlined instructions, we build up and
|
|
/// maintain a mapping of simplified values specific to this callsite. The
|
|
/// idea is to propagate any special information we have about arguments to
|
|
/// this call through the inlinable section of the function, and account for
|
|
/// likely simplifications post-inlining. The most important aspect we track
|
|
/// is CFG altering simplifications -- when we prove a basic block dead, that
|
|
/// can cause dramatic shifts in the cost of inlining a function.
|
|
DenseMap<Value *, Constant *> SimplifiedValues;
|
|
|
|
/// Keep track of the values which map back (through function arguments) to
|
|
/// allocas on the caller stack which could be simplified through SROA.
|
|
DenseMap<Value *, Value *> SROAArgValues;
|
|
|
|
/// The mapping of caller Alloca values to their accumulated cost savings. If
|
|
/// we have to disable SROA for one of the allocas, this tells us how much
|
|
/// cost must be added.
|
|
DenseMap<Value *, int> SROAArgCosts;
|
|
|
|
/// Keep track of values which map to a pointer base and constant offset.
|
|
DenseMap<Value *, std::pair<Value *, APInt>> ConstantOffsetPtrs;
|
|
|
|
// Custom simplification helper routines.
|
|
bool isAllocaDerivedArg(Value *V);
|
|
bool lookupSROAArgAndCost(Value *V, Value *&Arg,
|
|
DenseMap<Value *, int>::iterator &CostIt);
|
|
void disableSROA(DenseMap<Value *, int>::iterator CostIt);
|
|
void disableSROA(Value *V);
|
|
void accumulateSROACost(DenseMap<Value *, int>::iterator CostIt,
|
|
int InstructionCost);
|
|
bool isGEPFree(GetElementPtrInst &GEP);
|
|
bool accumulateGEPOffset(GEPOperator &GEP, APInt &Offset);
|
|
bool simplifyCallSite(Function *F, CallSite CS);
|
|
template <typename Callable>
|
|
bool simplifyInstruction(Instruction &I, Callable Evaluate);
|
|
ConstantInt *stripAndComputeInBoundsConstantOffsets(Value *&V);
|
|
|
|
/// Return true if the given argument to the function being considered for
|
|
/// inlining has the given attribute set either at the call site or the
|
|
/// function declaration. Primarily used to inspect call site specific
|
|
/// attributes since these can be more precise than the ones on the callee
|
|
/// itself.
|
|
bool paramHasAttr(Argument *A, Attribute::AttrKind Attr);
|
|
|
|
/// Return true if the given value is known non null within the callee if
|
|
/// inlined through this particular callsite.
|
|
bool isKnownNonNullInCallee(Value *V);
|
|
|
|
/// Update Threshold based on callsite properties such as callee
|
|
/// attributes and callee hotness for PGO builds. The Callee is explicitly
|
|
/// passed to support analyzing indirect calls whose target is inferred by
|
|
/// analysis.
|
|
void updateThreshold(CallSite CS, Function &Callee);
|
|
|
|
/// Return true if size growth is allowed when inlining the callee at CS.
|
|
bool allowSizeGrowth(CallSite CS);
|
|
|
|
// Custom analysis routines.
|
|
bool 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 *);
|
|
void visit(BasicBlock &);
|
|
|
|
// Provide base case for our instruction visit.
|
|
bool visitInstruction(Instruction &I);
|
|
|
|
// Our visit overrides.
|
|
bool visitAlloca(AllocaInst &I);
|
|
bool visitPHI(PHINode &I);
|
|
bool visitGetElementPtr(GetElementPtrInst &I);
|
|
bool visitBitCast(BitCastInst &I);
|
|
bool visitPtrToInt(PtrToIntInst &I);
|
|
bool visitIntToPtr(IntToPtrInst &I);
|
|
bool visitCastInst(CastInst &I);
|
|
bool visitUnaryInstruction(UnaryInstruction &I);
|
|
bool visitCmpInst(CmpInst &I);
|
|
bool visitSub(BinaryOperator &I);
|
|
bool visitBinaryOperator(BinaryOperator &I);
|
|
bool visitLoad(LoadInst &I);
|
|
bool visitStore(StoreInst &I);
|
|
bool visitExtractValue(ExtractValueInst &I);
|
|
bool visitInsertValue(InsertValueInst &I);
|
|
bool visitCallSite(CallSite CS);
|
|
bool visitReturnInst(ReturnInst &RI);
|
|
bool visitBranchInst(BranchInst &BI);
|
|
bool visitSwitchInst(SwitchInst &SI);
|
|
bool visitIndirectBrInst(IndirectBrInst &IBI);
|
|
bool visitResumeInst(ResumeInst &RI);
|
|
bool visitCleanupReturnInst(CleanupReturnInst &RI);
|
|
bool visitCatchReturnInst(CatchReturnInst &RI);
|
|
bool visitUnreachableInst(UnreachableInst &I);
|
|
|
|
public:
|
|
CallAnalyzer(const TargetTransformInfo &TTI,
|
|
std::function<AssumptionCache &(Function &)> &GetAssumptionCache,
|
|
Optional<function_ref<BlockFrequencyInfo &(Function &)>> &GetBFI,
|
|
ProfileSummaryInfo *PSI, Function &Callee, CallSite CSArg,
|
|
const InlineParams &Params)
|
|
: TTI(TTI), GetAssumptionCache(GetAssumptionCache), GetBFI(GetBFI),
|
|
PSI(PSI), F(Callee), DL(F.getParent()->getDataLayout()),
|
|
CandidateCS(CSArg), Params(Params), Threshold(Params.DefaultThreshold),
|
|
Cost(0), IsCallerRecursive(false), IsRecursiveCall(false),
|
|
ExposesReturnsTwice(false), HasDynamicAlloca(false),
|
|
ContainsNoDuplicateCall(false), HasReturn(false), HasIndirectBr(false),
|
|
HasFrameEscape(false), AllocatedSize(0), NumInstructions(0),
|
|
NumVectorInstructions(0), FiftyPercentVectorBonus(0),
|
|
TenPercentVectorBonus(0), VectorBonus(0), NumConstantArgs(0),
|
|
NumConstantOffsetPtrArgs(0), NumAllocaArgs(0), NumConstantPtrCmps(0),
|
|
NumConstantPtrDiffs(0), NumInstructionsSimplified(0),
|
|
SROACostSavings(0), SROACostSavingsLost(0) {}
|
|
|
|
bool 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;
|
|
unsigned NumAllocaArgs;
|
|
unsigned NumConstantPtrCmps;
|
|
unsigned NumConstantPtrDiffs;
|
|
unsigned NumInstructionsSimplified;
|
|
unsigned SROACostSavings;
|
|
unsigned SROACostSavingsLost;
|
|
|
|
void dump();
|
|
};
|
|
|
|
} // namespace
|
|
|
|
/// \brief Test whether the given value is an Alloca-derived function argument.
|
|
bool CallAnalyzer::isAllocaDerivedArg(Value *V) {
|
|
return SROAArgValues.count(V);
|
|
}
|
|
|
|
/// \brief Lookup the SROA-candidate argument and cost iterator which V maps to.
|
|
/// Returns false if V does not map to a SROA-candidate.
|
|
bool CallAnalyzer::lookupSROAArgAndCost(
|
|
Value *V, Value *&Arg, DenseMap<Value *, int>::iterator &CostIt) {
|
|
if (SROAArgValues.empty() || SROAArgCosts.empty())
|
|
return false;
|
|
|
|
DenseMap<Value *, Value *>::iterator ArgIt = SROAArgValues.find(V);
|
|
if (ArgIt == SROAArgValues.end())
|
|
return false;
|
|
|
|
Arg = ArgIt->second;
|
|
CostIt = SROAArgCosts.find(Arg);
|
|
return CostIt != SROAArgCosts.end();
|
|
}
|
|
|
|
/// \brief Disable SROA for the candidate marked by this cost iterator.
|
|
///
|
|
/// This marks the candidate as no longer viable for SROA, and adds the cost
|
|
/// savings associated with it back into the inline cost measurement.
|
|
void CallAnalyzer::disableSROA(DenseMap<Value *, int>::iterator CostIt) {
|
|
// If we're no longer able to perform SROA we need to undo its cost savings
|
|
// and prevent subsequent analysis.
|
|
Cost += CostIt->second;
|
|
SROACostSavings -= CostIt->second;
|
|
SROACostSavingsLost += CostIt->second;
|
|
SROAArgCosts.erase(CostIt);
|
|
}
|
|
|
|
/// \brief If 'V' maps to a SROA candidate, disable SROA for it.
|
|
void CallAnalyzer::disableSROA(Value *V) {
|
|
Value *SROAArg;
|
|
DenseMap<Value *, int>::iterator CostIt;
|
|
if (lookupSROAArgAndCost(V, SROAArg, CostIt))
|
|
disableSROA(CostIt);
|
|
}
|
|
|
|
/// \brief Accumulate the given cost for a particular SROA candidate.
|
|
void CallAnalyzer::accumulateSROACost(DenseMap<Value *, int>::iterator CostIt,
|
|
int InstructionCost) {
|
|
CostIt->second += InstructionCost;
|
|
SROACostSavings += InstructionCost;
|
|
}
|
|
|
|
/// \brief Accumulate a constant GEP offset into an APInt if possible.
|
|
///
|
|
/// Returns false if unable to compute the offset for any reason. Respects any
|
|
/// simplified values known during the analysis of this callsite.
|
|
bool CallAnalyzer::accumulateGEPOffset(GEPOperator &GEP, APInt &Offset) {
|
|
unsigned IntPtrWidth = DL.getPointerSizeInBits();
|
|
assert(IntPtrWidth == Offset.getBitWidth());
|
|
|
|
for (gep_type_iterator GTI = gep_type_begin(GEP), GTE = gep_type_end(GEP);
|
|
GTI != GTE; ++GTI) {
|
|
ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand());
|
|
if (!OpC)
|
|
if (Constant *SimpleOp = SimplifiedValues.lookup(GTI.getOperand()))
|
|
OpC = dyn_cast<ConstantInt>(SimpleOp);
|
|
if (!OpC)
|
|
return false;
|
|
if (OpC->isZero())
|
|
continue;
|
|
|
|
// Handle a struct index, which adds its field offset to the pointer.
|
|
if (StructType *STy = GTI.getStructTypeOrNull()) {
|
|
unsigned ElementIdx = OpC->getZExtValue();
|
|
const StructLayout *SL = DL.getStructLayout(STy);
|
|
Offset += APInt(IntPtrWidth, SL->getElementOffset(ElementIdx));
|
|
continue;
|
|
}
|
|
|
|
APInt TypeSize(IntPtrWidth, DL.getTypeAllocSize(GTI.getIndexedType()));
|
|
Offset += OpC->getValue().sextOrTrunc(IntPtrWidth) * TypeSize;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// \brief Use TTI to check whether a GEP is free.
|
|
///
|
|
/// Respects any simplified values known during the analysis of this callsite.
|
|
bool CallAnalyzer::isGEPFree(GetElementPtrInst &GEP) {
|
|
SmallVector<Value *, 4> Indices;
|
|
for (User::op_iterator I = GEP.idx_begin(), E = GEP.idx_end(); I != E; ++I)
|
|
if (Constant *SimpleOp = SimplifiedValues.lookup(*I))
|
|
Indices.push_back(SimpleOp);
|
|
else
|
|
Indices.push_back(*I);
|
|
return TargetTransformInfo::TCC_Free ==
|
|
TTI.getGEPCost(GEP.getSourceElementType(), GEP.getPointerOperand(),
|
|
Indices);
|
|
}
|
|
|
|
bool CallAnalyzer::visitAlloca(AllocaInst &I) {
|
|
// Check whether inlining will turn a dynamic alloca into a static
|
|
// alloca and handle that case.
|
|
if (I.isArrayAllocation()) {
|
|
Constant *Size = SimplifiedValues.lookup(I.getArraySize());
|
|
if (auto *AllocSize = dyn_cast_or_null<ConstantInt>(Size)) {
|
|
Type *Ty = I.getAllocatedType();
|
|
AllocatedSize = SaturatingMultiplyAdd(
|
|
AllocSize->getLimitedValue(), DL.getTypeAllocSize(Ty), AllocatedSize);
|
|
return Base::visitAlloca(I);
|
|
}
|
|
}
|
|
|
|
// Accumulate the allocated size.
|
|
if (I.isStaticAlloca()) {
|
|
Type *Ty = I.getAllocatedType();
|
|
AllocatedSize = SaturatingAdd(DL.getTypeAllocSize(Ty), AllocatedSize);
|
|
}
|
|
|
|
// We will happily inline static alloca instructions.
|
|
if (I.isStaticAlloca())
|
|
return Base::visitAlloca(I);
|
|
|
|
// FIXME: This is overly conservative. Dynamic allocas are inefficient for
|
|
// a variety of reasons, and so we would like to not inline them into
|
|
// functions which don't currently have a dynamic alloca. This simply
|
|
// disables inlining altogether in the presence of a dynamic alloca.
|
|
HasDynamicAlloca = true;
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::visitPHI(PHINode &I) {
|
|
// FIXME: We should potentially be tracking values through phi nodes,
|
|
// especially when they collapse to a single value due to deleted CFG edges
|
|
// during inlining.
|
|
|
|
// FIXME: We need to propagate SROA *disabling* through phi nodes, even
|
|
// though we don't want to propagate it's bonuses. The idea is to disable
|
|
// SROA if it *might* be used in an inappropriate manner.
|
|
|
|
// Phi nodes are always zero-cost.
|
|
return true;
|
|
}
|
|
|
|
bool CallAnalyzer::visitGetElementPtr(GetElementPtrInst &I) {
|
|
Value *SROAArg;
|
|
DenseMap<Value *, int>::iterator CostIt;
|
|
bool SROACandidate =
|
|
lookupSROAArgAndCost(I.getPointerOperand(), SROAArg, CostIt);
|
|
|
|
// Try to fold GEPs of constant-offset call site argument pointers. This
|
|
// requires target data and inbounds GEPs.
|
|
if (I.isInBounds()) {
|
|
// Check if we have a base + offset for the pointer.
|
|
Value *Ptr = I.getPointerOperand();
|
|
std::pair<Value *, APInt> BaseAndOffset = ConstantOffsetPtrs.lookup(Ptr);
|
|
if (BaseAndOffset.first) {
|
|
// Check if the offset of this GEP is constant, and if so accumulate it
|
|
// into Offset.
|
|
if (!accumulateGEPOffset(cast<GEPOperator>(I), BaseAndOffset.second)) {
|
|
// Non-constant GEPs aren't folded, and disable SROA.
|
|
if (SROACandidate)
|
|
disableSROA(CostIt);
|
|
return isGEPFree(I);
|
|
}
|
|
|
|
// Add the result as a new mapping to Base + Offset.
|
|
ConstantOffsetPtrs[&I] = BaseAndOffset;
|
|
|
|
// Also handle SROA candidates here, we already know that the GEP is
|
|
// all-constant indexed.
|
|
if (SROACandidate)
|
|
SROAArgValues[&I] = SROAArg;
|
|
|
|
return true;
|
|
}
|
|
}
|
|
|
|
// Lambda to check whether a GEP's indices are all constant.
|
|
auto IsGEPOffsetConstant = [&](GetElementPtrInst &GEP) {
|
|
for (User::op_iterator I = GEP.idx_begin(), E = GEP.idx_end(); I != E; ++I)
|
|
if (!isa<Constant>(*I) && !SimplifiedValues.lookup(*I))
|
|
return false;
|
|
return true;
|
|
};
|
|
|
|
if (IsGEPOffsetConstant(I)) {
|
|
if (SROACandidate)
|
|
SROAArgValues[&I] = SROAArg;
|
|
|
|
// Constant GEPs are modeled as free.
|
|
return true;
|
|
}
|
|
|
|
// Variable GEPs will require math and will disable SROA.
|
|
if (SROACandidate)
|
|
disableSROA(CostIt);
|
|
return isGEPFree(I);
|
|
}
|
|
|
|
/// Simplify \p I if its operands are constants and update SimplifiedValues.
|
|
/// \p Evaluate is a callable specific to instruction type that evaluates the
|
|
/// instruction when all the operands are constants.
|
|
template <typename Callable>
|
|
bool CallAnalyzer::simplifyInstruction(Instruction &I, Callable Evaluate) {
|
|
SmallVector<Constant *, 2> COps;
|
|
for (Value *Op : I.operands()) {
|
|
Constant *COp = dyn_cast<Constant>(Op);
|
|
if (!COp)
|
|
COp = SimplifiedValues.lookup(Op);
|
|
if (!COp)
|
|
return false;
|
|
COps.push_back(COp);
|
|
}
|
|
auto *C = Evaluate(COps);
|
|
if (!C)
|
|
return false;
|
|
SimplifiedValues[&I] = C;
|
|
return true;
|
|
}
|
|
|
|
bool CallAnalyzer::visitBitCast(BitCastInst &I) {
|
|
// Propagate constants through bitcasts.
|
|
if (simplifyInstruction(I, [&](SmallVectorImpl<Constant *> &COps) {
|
|
return ConstantExpr::getBitCast(COps[0], I.getType());
|
|
}))
|
|
return true;
|
|
|
|
// Track base/offsets through casts
|
|
std::pair<Value *, APInt> BaseAndOffset =
|
|
ConstantOffsetPtrs.lookup(I.getOperand(0));
|
|
// Casts don't change the offset, just wrap it up.
|
|
if (BaseAndOffset.first)
|
|
ConstantOffsetPtrs[&I] = BaseAndOffset;
|
|
|
|
// Also look for SROA candidates here.
|
|
Value *SROAArg;
|
|
DenseMap<Value *, int>::iterator CostIt;
|
|
if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt))
|
|
SROAArgValues[&I] = SROAArg;
|
|
|
|
// Bitcasts are always zero cost.
|
|
return true;
|
|
}
|
|
|
|
bool CallAnalyzer::visitPtrToInt(PtrToIntInst &I) {
|
|
// Propagate constants through ptrtoint.
|
|
if (simplifyInstruction(I, [&](SmallVectorImpl<Constant *> &COps) {
|
|
return ConstantExpr::getPtrToInt(COps[0], I.getType());
|
|
}))
|
|
return true;
|
|
|
|
// Track base/offset pairs when converted to a plain integer provided the
|
|
// integer is large enough to represent the pointer.
|
|
unsigned IntegerSize = I.getType()->getScalarSizeInBits();
|
|
if (IntegerSize >= DL.getPointerSizeInBits()) {
|
|
std::pair<Value *, APInt> BaseAndOffset =
|
|
ConstantOffsetPtrs.lookup(I.getOperand(0));
|
|
if (BaseAndOffset.first)
|
|
ConstantOffsetPtrs[&I] = BaseAndOffset;
|
|
}
|
|
|
|
// This is really weird. Technically, ptrtoint will disable SROA. However,
|
|
// unless that ptrtoint is *used* somewhere in the live basic blocks after
|
|
// inlining, it will be nuked, and SROA should proceed. All of the uses which
|
|
// would block SROA would also block SROA if applied directly to a pointer,
|
|
// and so we can just add the integer in here. The only places where SROA is
|
|
// preserved either cannot fire on an integer, or won't in-and-of themselves
|
|
// disable SROA (ext) w/o some later use that we would see and disable.
|
|
Value *SROAArg;
|
|
DenseMap<Value *, int>::iterator CostIt;
|
|
if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt))
|
|
SROAArgValues[&I] = SROAArg;
|
|
|
|
return TargetTransformInfo::TCC_Free == TTI.getUserCost(&I);
|
|
}
|
|
|
|
bool CallAnalyzer::visitIntToPtr(IntToPtrInst &I) {
|
|
// Propagate constants through ptrtoint.
|
|
if (simplifyInstruction(I, [&](SmallVectorImpl<Constant *> &COps) {
|
|
return ConstantExpr::getIntToPtr(COps[0], I.getType());
|
|
}))
|
|
return true;
|
|
|
|
// Track base/offset pairs when round-tripped through a pointer without
|
|
// modifications provided the integer is not too large.
|
|
Value *Op = I.getOperand(0);
|
|
unsigned IntegerSize = Op->getType()->getScalarSizeInBits();
|
|
if (IntegerSize <= DL.getPointerSizeInBits()) {
|
|
std::pair<Value *, APInt> BaseAndOffset = ConstantOffsetPtrs.lookup(Op);
|
|
if (BaseAndOffset.first)
|
|
ConstantOffsetPtrs[&I] = BaseAndOffset;
|
|
}
|
|
|
|
// "Propagate" SROA here in the same manner as we do for ptrtoint above.
|
|
Value *SROAArg;
|
|
DenseMap<Value *, int>::iterator CostIt;
|
|
if (lookupSROAArgAndCost(Op, SROAArg, CostIt))
|
|
SROAArgValues[&I] = SROAArg;
|
|
|
|
return TargetTransformInfo::TCC_Free == TTI.getUserCost(&I);
|
|
}
|
|
|
|
bool CallAnalyzer::visitCastInst(CastInst &I) {
|
|
// Propagate constants through ptrtoint.
|
|
if (simplifyInstruction(I, [&](SmallVectorImpl<Constant *> &COps) {
|
|
return ConstantExpr::getCast(I.getOpcode(), COps[0], I.getType());
|
|
}))
|
|
return true;
|
|
|
|
// Disable SROA in the face of arbitrary casts we don't whitelist elsewhere.
|
|
disableSROA(I.getOperand(0));
|
|
|
|
return TargetTransformInfo::TCC_Free == TTI.getUserCost(&I);
|
|
}
|
|
|
|
bool CallAnalyzer::visitUnaryInstruction(UnaryInstruction &I) {
|
|
Value *Operand = I.getOperand(0);
|
|
if (simplifyInstruction(I, [&](SmallVectorImpl<Constant *> &COps) {
|
|
return ConstantFoldInstOperands(&I, COps[0], DL);
|
|
}))
|
|
return true;
|
|
|
|
// Disable any SROA on the argument to arbitrary unary operators.
|
|
disableSROA(Operand);
|
|
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::paramHasAttr(Argument *A, Attribute::AttrKind Attr) {
|
|
return CandidateCS.paramHasAttr(A->getArgNo(), Attr);
|
|
}
|
|
|
|
bool CallAnalyzer::isKnownNonNullInCallee(Value *V) {
|
|
// Does the *call site* have the NonNull attribute set on an argument? We
|
|
// use the attribute on the call site to memoize any analysis done in the
|
|
// caller. This will also trip if the callee function has a non-null
|
|
// parameter attribute, but that's a less interesting case because hopefully
|
|
// the callee would already have been simplified based on that.
|
|
if (Argument *A = dyn_cast<Argument>(V))
|
|
if (paramHasAttr(A, Attribute::NonNull))
|
|
return true;
|
|
|
|
// Is this an alloca in the caller? This is distinct from the attribute case
|
|
// above because attributes aren't updated within the inliner itself and we
|
|
// always want to catch the alloca derived case.
|
|
if (isAllocaDerivedArg(V))
|
|
// We can actually predict the result of comparisons between an
|
|
// alloca-derived value and null. Note that this fires regardless of
|
|
// SROA firing.
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::allowSizeGrowth(CallSite CS) {
|
|
// If the normal destination of the invoke or the parent block of the call
|
|
// site is unreachable-terminated, there is little point in inlining this
|
|
// unless there is literally zero cost.
|
|
// FIXME: Note that it is possible that an unreachable-terminated block has a
|
|
// hot entry. For example, in below scenario inlining hot_call_X() may be
|
|
// beneficial :
|
|
// main() {
|
|
// hot_call_1();
|
|
// ...
|
|
// hot_call_N()
|
|
// exit(0);
|
|
// }
|
|
// For now, we are not handling this corner case here as it is rare in real
|
|
// code. In future, we should elaborate this based on BPI and BFI in more
|
|
// general threshold adjusting heuristics in updateThreshold().
|
|
Instruction *Instr = CS.getInstruction();
|
|
if (InvokeInst *II = dyn_cast<InvokeInst>(Instr)) {
|
|
if (isa<UnreachableInst>(II->getNormalDest()->getTerminator()))
|
|
return false;
|
|
} else if (isa<UnreachableInst>(Instr->getParent()->getTerminator()))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
void CallAnalyzer::updateThreshold(CallSite CS, Function &Callee) {
|
|
// If no size growth is allowed for this inlining, set Threshold to 0.
|
|
if (!allowSizeGrowth(CS)) {
|
|
Threshold = 0;
|
|
return;
|
|
}
|
|
|
|
Function *Caller = CS.getCaller();
|
|
|
|
// return min(A, B) if B is valid.
|
|
auto MinIfValid = [](int A, Optional<int> B) {
|
|
return B ? std::min(A, B.getValue()) : A;
|
|
};
|
|
|
|
// return max(A, B) if B is valid.
|
|
auto MaxIfValid = [](int A, Optional<int> B) {
|
|
return B ? std::max(A, B.getValue()) : A;
|
|
};
|
|
|
|
// Use the OptMinSizeThreshold or OptSizeThreshold knob if they are available
|
|
// and reduce the threshold if the caller has the necessary attribute.
|
|
if (Caller->optForMinSize())
|
|
Threshold = MinIfValid(Threshold, Params.OptMinSizeThreshold);
|
|
else if (Caller->optForSize())
|
|
Threshold = MinIfValid(Threshold, Params.OptSizeThreshold);
|
|
|
|
// Adjust the threshold based on inlinehint attribute and profile based
|
|
// hotness information if the caller does not have MinSize attribute.
|
|
if (!Caller->optForMinSize()) {
|
|
if (Callee.hasFnAttribute(Attribute::InlineHint))
|
|
Threshold = MaxIfValid(Threshold, Params.HintThreshold);
|
|
if (PSI) {
|
|
BlockFrequencyInfo *CallerBFI = GetBFI ? &((*GetBFI)(*Caller)) : nullptr;
|
|
if (PSI->isHotCallSite(CS, CallerBFI)) {
|
|
DEBUG(dbgs() << "Hot callsite.\n");
|
|
Threshold = Params.HotCallSiteThreshold.getValue();
|
|
} else if (PSI->isFunctionEntryHot(&Callee)) {
|
|
DEBUG(dbgs() << "Hot callee.\n");
|
|
// If callsite hotness can not be determined, we may still know
|
|
// that the callee is hot and treat it as a weaker hint for threshold
|
|
// increase.
|
|
Threshold = MaxIfValid(Threshold, Params.HintThreshold);
|
|
} else if (PSI->isColdCallSite(CS, CallerBFI)) {
|
|
DEBUG(dbgs() << "Cold callsite.\n");
|
|
Threshold = MinIfValid(Threshold, Params.ColdCallSiteThreshold);
|
|
} else if (PSI->isFunctionEntryCold(&Callee)) {
|
|
DEBUG(dbgs() << "Cold callee.\n");
|
|
Threshold = MinIfValid(Threshold, Params.ColdThreshold);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Finally, take the target-specific inlining threshold multiplier into
|
|
// account.
|
|
Threshold *= TTI.getInliningThresholdMultiplier();
|
|
}
|
|
|
|
bool CallAnalyzer::visitCmpInst(CmpInst &I) {
|
|
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
|
|
// First try to handle simplified comparisons.
|
|
if (simplifyInstruction(I, [&](SmallVectorImpl<Constant *> &COps) {
|
|
return ConstantExpr::getCompare(I.getPredicate(), COps[0], COps[1]);
|
|
}))
|
|
return true;
|
|
|
|
if (I.getOpcode() == Instruction::FCmp)
|
|
return false;
|
|
|
|
// Otherwise look for a comparison between constant offset pointers with
|
|
// a common base.
|
|
Value *LHSBase, *RHSBase;
|
|
APInt LHSOffset, RHSOffset;
|
|
std::tie(LHSBase, LHSOffset) = ConstantOffsetPtrs.lookup(LHS);
|
|
if (LHSBase) {
|
|
std::tie(RHSBase, RHSOffset) = ConstantOffsetPtrs.lookup(RHS);
|
|
if (RHSBase && LHSBase == RHSBase) {
|
|
// We have common bases, fold the icmp to a constant based on the
|
|
// offsets.
|
|
Constant *CLHS = ConstantInt::get(LHS->getContext(), LHSOffset);
|
|
Constant *CRHS = ConstantInt::get(RHS->getContext(), RHSOffset);
|
|
if (Constant *C = ConstantExpr::getICmp(I.getPredicate(), CLHS, CRHS)) {
|
|
SimplifiedValues[&I] = C;
|
|
++NumConstantPtrCmps;
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
|
|
// If the comparison is an equality comparison with null, we can simplify it
|
|
// if we know the value (argument) can't be null
|
|
if (I.isEquality() && isa<ConstantPointerNull>(I.getOperand(1)) &&
|
|
isKnownNonNullInCallee(I.getOperand(0))) {
|
|
bool IsNotEqual = I.getPredicate() == CmpInst::ICMP_NE;
|
|
SimplifiedValues[&I] = IsNotEqual ? ConstantInt::getTrue(I.getType())
|
|
: ConstantInt::getFalse(I.getType());
|
|
return true;
|
|
}
|
|
// Finally check for SROA candidates in comparisons.
|
|
Value *SROAArg;
|
|
DenseMap<Value *, int>::iterator CostIt;
|
|
if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) {
|
|
if (isa<ConstantPointerNull>(I.getOperand(1))) {
|
|
accumulateSROACost(CostIt, InlineConstants::InstrCost);
|
|
return true;
|
|
}
|
|
|
|
disableSROA(CostIt);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::visitSub(BinaryOperator &I) {
|
|
// Try to handle a special case: we can fold computing the difference of two
|
|
// constant-related pointers.
|
|
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
|
|
Value *LHSBase, *RHSBase;
|
|
APInt LHSOffset, RHSOffset;
|
|
std::tie(LHSBase, LHSOffset) = ConstantOffsetPtrs.lookup(LHS);
|
|
if (LHSBase) {
|
|
std::tie(RHSBase, RHSOffset) = ConstantOffsetPtrs.lookup(RHS);
|
|
if (RHSBase && LHSBase == RHSBase) {
|
|
// We have common bases, fold the subtract to a constant based on the
|
|
// offsets.
|
|
Constant *CLHS = ConstantInt::get(LHS->getContext(), LHSOffset);
|
|
Constant *CRHS = ConstantInt::get(RHS->getContext(), RHSOffset);
|
|
if (Constant *C = ConstantExpr::getSub(CLHS, CRHS)) {
|
|
SimplifiedValues[&I] = C;
|
|
++NumConstantPtrDiffs;
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Otherwise, fall back to the generic logic for simplifying and handling
|
|
// instructions.
|
|
return Base::visitSub(I);
|
|
}
|
|
|
|
bool CallAnalyzer::visitBinaryOperator(BinaryOperator &I) {
|
|
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
|
|
auto Evaluate = [&](SmallVectorImpl<Constant *> &COps) {
|
|
Value *SimpleV = nullptr;
|
|
if (auto FI = dyn_cast<FPMathOperator>(&I))
|
|
SimpleV = SimplifyFPBinOp(I.getOpcode(), COps[0], COps[1],
|
|
FI->getFastMathFlags(), DL);
|
|
else
|
|
SimpleV = SimplifyBinOp(I.getOpcode(), COps[0], COps[1], DL);
|
|
return dyn_cast_or_null<Constant>(SimpleV);
|
|
};
|
|
|
|
if (simplifyInstruction(I, Evaluate))
|
|
return true;
|
|
|
|
// Disable any SROA on arguments to arbitrary, unsimplified binary operators.
|
|
disableSROA(LHS);
|
|
disableSROA(RHS);
|
|
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::visitLoad(LoadInst &I) {
|
|
Value *SROAArg;
|
|
DenseMap<Value *, int>::iterator CostIt;
|
|
if (lookupSROAArgAndCost(I.getPointerOperand(), SROAArg, CostIt)) {
|
|
if (I.isSimple()) {
|
|
accumulateSROACost(CostIt, InlineConstants::InstrCost);
|
|
return true;
|
|
}
|
|
|
|
disableSROA(CostIt);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::visitStore(StoreInst &I) {
|
|
Value *SROAArg;
|
|
DenseMap<Value *, int>::iterator CostIt;
|
|
if (lookupSROAArgAndCost(I.getPointerOperand(), SROAArg, CostIt)) {
|
|
if (I.isSimple()) {
|
|
accumulateSROACost(CostIt, InlineConstants::InstrCost);
|
|
return true;
|
|
}
|
|
|
|
disableSROA(CostIt);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::visitExtractValue(ExtractValueInst &I) {
|
|
// Constant folding for extract value is trivial.
|
|
if (simplifyInstruction(I, [&](SmallVectorImpl<Constant *> &COps) {
|
|
return ConstantExpr::getExtractValue(COps[0], I.getIndices());
|
|
}))
|
|
return true;
|
|
|
|
// SROA can look through these but give them a cost.
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::visitInsertValue(InsertValueInst &I) {
|
|
// Constant folding for insert value is trivial.
|
|
if (simplifyInstruction(I, [&](SmallVectorImpl<Constant *> &COps) {
|
|
return ConstantExpr::getInsertValue(/*AggregateOperand*/ COps[0],
|
|
/*InsertedValueOperand*/ COps[1],
|
|
I.getIndices());
|
|
}))
|
|
return true;
|
|
|
|
// SROA can look through these but give them a cost.
|
|
return false;
|
|
}
|
|
|
|
/// \brief Try to simplify a call site.
|
|
///
|
|
/// Takes a concrete function and callsite and tries to actually simplify it by
|
|
/// analyzing the arguments and call itself with instsimplify. Returns true if
|
|
/// it has simplified the callsite to some other entity (a constant), making it
|
|
/// free.
|
|
bool CallAnalyzer::simplifyCallSite(Function *F, CallSite CS) {
|
|
// FIXME: Using the instsimplify logic directly for this is inefficient
|
|
// because we have to continually rebuild the argument list even when no
|
|
// simplifications can be performed. Until that is fixed with remapping
|
|
// inside of instsimplify, directly constant fold calls here.
|
|
if (!canConstantFoldCallTo(F))
|
|
return false;
|
|
|
|
// Try to re-map the arguments to constants.
|
|
SmallVector<Constant *, 4> ConstantArgs;
|
|
ConstantArgs.reserve(CS.arg_size());
|
|
for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); I != E;
|
|
++I) {
|
|
Constant *C = dyn_cast<Constant>(*I);
|
|
if (!C)
|
|
C = dyn_cast_or_null<Constant>(SimplifiedValues.lookup(*I));
|
|
if (!C)
|
|
return false; // This argument doesn't map to a constant.
|
|
|
|
ConstantArgs.push_back(C);
|
|
}
|
|
if (Constant *C = ConstantFoldCall(F, ConstantArgs)) {
|
|
SimplifiedValues[CS.getInstruction()] = C;
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::visitCallSite(CallSite CS) {
|
|
if (CS.hasFnAttr(Attribute::ReturnsTwice) &&
|
|
!F.hasFnAttribute(Attribute::ReturnsTwice)) {
|
|
// This aborts the entire analysis.
|
|
ExposesReturnsTwice = true;
|
|
return false;
|
|
}
|
|
if (CS.isCall() && cast<CallInst>(CS.getInstruction())->cannotDuplicate())
|
|
ContainsNoDuplicateCall = true;
|
|
|
|
if (Function *F = CS.getCalledFunction()) {
|
|
// When we have a concrete function, first try to simplify it directly.
|
|
if (simplifyCallSite(F, CS))
|
|
return true;
|
|
|
|
// Next check if it is an intrinsic we know about.
|
|
// FIXME: Lift this into part of the InstVisitor.
|
|
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(CS.getInstruction())) {
|
|
switch (II->getIntrinsicID()) {
|
|
default:
|
|
return Base::visitCallSite(CS);
|
|
|
|
case Intrinsic::load_relative:
|
|
// This is normally lowered to 4 LLVM instructions.
|
|
Cost += 3 * InlineConstants::InstrCost;
|
|
return false;
|
|
|
|
case Intrinsic::memset:
|
|
case Intrinsic::memcpy:
|
|
case Intrinsic::memmove:
|
|
// SROA can usually chew through these intrinsics, but they aren't free.
|
|
return false;
|
|
case Intrinsic::localescape:
|
|
HasFrameEscape = true;
|
|
return false;
|
|
}
|
|
}
|
|
|
|
if (F == CS.getInstruction()->getParent()->getParent()) {
|
|
// This flag will fully abort the analysis, so don't bother with anything
|
|
// else.
|
|
IsRecursiveCall = true;
|
|
return false;
|
|
}
|
|
|
|
if (TTI.isLoweredToCall(F)) {
|
|
// We account for the average 1 instruction per call argument setup
|
|
// here.
|
|
Cost += CS.arg_size() * InlineConstants::InstrCost;
|
|
|
|
// Everything other than inline ASM will also have a significant cost
|
|
// merely from making the call.
|
|
if (!isa<InlineAsm>(CS.getCalledValue()))
|
|
Cost += InlineConstants::CallPenalty;
|
|
}
|
|
|
|
return Base::visitCallSite(CS);
|
|
}
|
|
|
|
// Otherwise we're in a very special case -- an indirect function call. See
|
|
// if we can be particularly clever about this.
|
|
Value *Callee = CS.getCalledValue();
|
|
|
|
// First, pay the price of the argument setup. We account for the average
|
|
// 1 instruction per call argument setup here.
|
|
Cost += CS.arg_size() * InlineConstants::InstrCost;
|
|
|
|
// Next, check if this happens to be an indirect function call to a known
|
|
// function in this inline context. If not, we've done all we can.
|
|
Function *F = dyn_cast_or_null<Function>(SimplifiedValues.lookup(Callee));
|
|
if (!F)
|
|
return Base::visitCallSite(CS);
|
|
|
|
// If we have a constant that we are calling as a function, we can peer
|
|
// through it and see the function target. This happens not infrequently
|
|
// during devirtualization and so we want to give it a hefty bonus for
|
|
// inlining, but cap that bonus in the event that inlining wouldn't pan
|
|
// out. Pretend to inline the function, with a custom threshold.
|
|
auto IndirectCallParams = Params;
|
|
IndirectCallParams.DefaultThreshold = InlineConstants::IndirectCallThreshold;
|
|
CallAnalyzer CA(TTI, GetAssumptionCache, GetBFI, PSI, *F, CS,
|
|
IndirectCallParams);
|
|
if (CA.analyzeCall(CS)) {
|
|
// We were able to inline the indirect call! Subtract the cost from the
|
|
// threshold to get the bonus we want to apply, but don't go below zero.
|
|
Cost -= std::max(0, CA.getThreshold() - CA.getCost());
|
|
}
|
|
|
|
return Base::visitCallSite(CS);
|
|
}
|
|
|
|
bool CallAnalyzer::visitReturnInst(ReturnInst &RI) {
|
|
// At least one return instruction will be free after inlining.
|
|
bool Free = !HasReturn;
|
|
HasReturn = true;
|
|
return Free;
|
|
}
|
|
|
|
bool CallAnalyzer::visitBranchInst(BranchInst &BI) {
|
|
// We model unconditional branches as essentially free -- they really
|
|
// shouldn't exist at all, but handling them makes the behavior of the
|
|
// inliner more regular and predictable. Interestingly, conditional branches
|
|
// which will fold away are also free.
|
|
return BI.isUnconditional() || isa<ConstantInt>(BI.getCondition()) ||
|
|
dyn_cast_or_null<ConstantInt>(
|
|
SimplifiedValues.lookup(BI.getCondition()));
|
|
}
|
|
|
|
bool CallAnalyzer::visitSwitchInst(SwitchInst &SI) {
|
|
// We model unconditional switches as free, see the comments on handling
|
|
// branches.
|
|
if (isa<ConstantInt>(SI.getCondition()))
|
|
return true;
|
|
if (Value *V = SimplifiedValues.lookup(SI.getCondition()))
|
|
if (isa<ConstantInt>(V))
|
|
return true;
|
|
|
|
if (EnableGenericSwitchCost) {
|
|
// Assume the most general case where the swith is lowered into
|
|
// either a jump table, bit test, or a balanced binary tree consisting of
|
|
// case clusters without merging adjacent clusters with the same
|
|
// destination. We do not consider the switches that are lowered with a mix
|
|
// of jump table/bit test/binary search tree. The cost of the switch is
|
|
// proportional to the size of the tree or the size of jump table range.
|
|
|
|
// Exit early for a large switch, assuming one case needs at least one
|
|
// instruction.
|
|
// FIXME: This is not true for a bit test, but ignore such case for now to
|
|
// save compile-time.
|
|
int64_t CostLowerBound =
|
|
std::min((int64_t)INT_MAX,
|
|
(int64_t)SI.getNumCases() * InlineConstants::InstrCost + Cost);
|
|
|
|
if (CostLowerBound > Threshold) {
|
|
Cost = CostLowerBound;
|
|
return false;
|
|
}
|
|
|
|
unsigned JumpTableSize = 0;
|
|
unsigned NumCaseCluster =
|
|
TTI.getEstimatedNumberOfCaseClusters(SI, JumpTableSize);
|
|
|
|
// If suitable for a jump table, consider the cost for the table size and
|
|
// branch to destination.
|
|
if (JumpTableSize) {
|
|
int64_t JTCost = (int64_t)JumpTableSize * InlineConstants::InstrCost +
|
|
4 * InlineConstants::InstrCost;
|
|
Cost = std::min((int64_t)INT_MAX, JTCost + Cost);
|
|
return false;
|
|
}
|
|
|
|
// Considering forming a binary search, we should find the number of nodes
|
|
// which is same as the number of comparisons when lowered. For a given
|
|
// number of clusters, n, we can define a recursive function, f(n), to find
|
|
// the number of nodes in the tree. The recursion is :
|
|
// f(n) = 1 + f(n/2) + f (n - n/2), when n > 3,
|
|
// and f(n) = n, when n <= 3.
|
|
// This will lead a binary tree where the leaf should be either f(2) or f(3)
|
|
// when n > 3. So, the number of comparisons from leaves should be n, while
|
|
// the number of non-leaf should be :
|
|
// 2^(log2(n) - 1) - 1
|
|
// = 2^log2(n) * 2^-1 - 1
|
|
// = n / 2 - 1.
|
|
// Considering comparisons from leaf and non-leaf nodes, we can estimate the
|
|
// number of comparisons in a simple closed form :
|
|
// n + n / 2 - 1 = n * 3 / 2 - 1
|
|
if (NumCaseCluster <= 3) {
|
|
// Suppose a comparison includes one compare and one conditional branch.
|
|
Cost += NumCaseCluster * 2 * InlineConstants::InstrCost;
|
|
return false;
|
|
}
|
|
int64_t ExpectedNumberOfCompare = 3 * (uint64_t)NumCaseCluster / 2 - 1;
|
|
uint64_t SwitchCost =
|
|
ExpectedNumberOfCompare * 2 * InlineConstants::InstrCost;
|
|
Cost = std::min((uint64_t)INT_MAX, SwitchCost + Cost);
|
|
return false;
|
|
}
|
|
|
|
// Use a simple switch cost model where we accumulate a cost proportional to
|
|
// the number of distinct successor blocks. This fan-out in the CFG cannot
|
|
// be represented for free even if we can represent the core switch as a
|
|
// jumptable that takes a single instruction.
|
|
///
|
|
// NB: We convert large switches which are just used to initialize large phi
|
|
// nodes to lookup tables instead in simplify-cfg, so this shouldn't prevent
|
|
// inlining those. It will prevent inlining in cases where the optimization
|
|
// does not (yet) fire.
|
|
SmallPtrSet<BasicBlock *, 8> SuccessorBlocks;
|
|
SuccessorBlocks.insert(SI.getDefaultDest());
|
|
for (auto Case : SI.cases())
|
|
SuccessorBlocks.insert(Case.getCaseSuccessor());
|
|
// Add cost corresponding to the number of distinct destinations. The first
|
|
// we model as free because of fallthrough.
|
|
Cost += (SuccessorBlocks.size() - 1) * InlineConstants::InstrCost;
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::visitIndirectBrInst(IndirectBrInst &IBI) {
|
|
// We never want to inline functions that contain an indirectbr. This is
|
|
// incorrect because all the blockaddress's (in static global initializers
|
|
// for example) would be referring to the original function, and this
|
|
// indirect jump would jump from the inlined copy of the function into the
|
|
// original function which is extremely undefined behavior.
|
|
// FIXME: This logic isn't really right; we can safely inline functions with
|
|
// indirectbr's as long as no other function or global references the
|
|
// blockaddress of a block within the current function.
|
|
HasIndirectBr = true;
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::visitResumeInst(ResumeInst &RI) {
|
|
// FIXME: It's not clear that a single instruction is an accurate model for
|
|
// the inline cost of a resume instruction.
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::visitCleanupReturnInst(CleanupReturnInst &CRI) {
|
|
// FIXME: It's not clear that a single instruction is an accurate model for
|
|
// the inline cost of a cleanupret instruction.
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::visitCatchReturnInst(CatchReturnInst &CRI) {
|
|
// FIXME: It's not clear that a single instruction is an accurate model for
|
|
// the inline cost of a catchret instruction.
|
|
return false;
|
|
}
|
|
|
|
bool CallAnalyzer::visitUnreachableInst(UnreachableInst &I) {
|
|
// FIXME: It might be reasonably to discount the cost of instructions leading
|
|
// to unreachable as they have the lowest possible impact on both runtime and
|
|
// code size.
|
|
return true; // No actual code is needed for unreachable.
|
|
}
|
|
|
|
bool CallAnalyzer::visitInstruction(Instruction &I) {
|
|
// Some instructions are free. All of the free intrinsics can also be
|
|
// handled by SROA, etc.
|
|
if (TargetTransformInfo::TCC_Free == TTI.getUserCost(&I))
|
|
return true;
|
|
|
|
// We found something we don't understand or can't handle. Mark any SROA-able
|
|
// values in the operand list as no longer viable.
|
|
for (User::op_iterator OI = I.op_begin(), OE = I.op_end(); OI != OE; ++OI)
|
|
disableSROA(*OI);
|
|
|
|
return false;
|
|
}
|
|
|
|
/// \brief 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) {
|
|
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.
|
|
if (isa<DbgInfoIntrinsic>(I))
|
|
continue;
|
|
|
|
// Skip ephemeral values.
|
|
if (EphValues.count(&*I))
|
|
continue;
|
|
|
|
++NumInstructions;
|
|
if (isa<ExtractElementInst>(I) || I->getType()->isVectorTy())
|
|
++NumVectorInstructions;
|
|
|
|
// If the instruction is floating point, and the target says this operation
|
|
// is expensive or the function has the "use-soft-float" attribute, this may
|
|
// eventually become a library call. Treat the cost as such.
|
|
if (I->getType()->isFloatingPointTy()) {
|
|
// If the function has the "use-soft-float" attribute, mark it as
|
|
// expensive.
|
|
if (TTI.getFPOpCost(I->getType()) == TargetTransformInfo::TCC_Expensive ||
|
|
(F.getFnAttribute("use-soft-float").getValueAsString() == "true"))
|
|
Cost += InlineConstants::CallPenalty;
|
|
}
|
|
|
|
// If the instruction simplified to a constant, there is no cost to this
|
|
// instruction. Visit the instructions using our InstVisitor to account for
|
|
// all of the per-instruction logic. The visit tree returns true if we
|
|
// consumed the instruction in any way, and false if the instruction's base
|
|
// cost should count against inlining.
|
|
if (Base::visit(&*I))
|
|
++NumInstructionsSimplified;
|
|
else
|
|
Cost += InlineConstants::InstrCost;
|
|
|
|
// If the visit this instruction detected an uninlinable pattern, abort.
|
|
if (IsRecursiveCall || ExposesReturnsTwice || HasDynamicAlloca ||
|
|
HasIndirectBr || HasFrameEscape)
|
|
return false;
|
|
|
|
// 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)
|
|
return false;
|
|
|
|
// 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)
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/// \brief Compute the base pointer and cumulative constant offsets for V.
|
|
///
|
|
/// This strips all constant offsets off of V, leaving it the base pointer, and
|
|
/// accumulates the total constant offset applied in the returned constant. It
|
|
/// returns 0 if V is not a pointer, and returns the constant '0' if there are
|
|
/// no constant offsets applied.
|
|
ConstantInt *CallAnalyzer::stripAndComputeInBoundsConstantOffsets(Value *&V) {
|
|
if (!V->getType()->isPointerTy())
|
|
return nullptr;
|
|
|
|
unsigned IntPtrWidth = DL.getPointerSizeInBits();
|
|
APInt Offset = APInt::getNullValue(IntPtrWidth);
|
|
|
|
// Even though we don't look through PHI nodes, we could be called on an
|
|
// instruction in an unreachable block, which may be on a cycle.
|
|
SmallPtrSet<Value *, 4> Visited;
|
|
Visited.insert(V);
|
|
do {
|
|
if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
|
|
if (!GEP->isInBounds() || !accumulateGEPOffset(*GEP, Offset))
|
|
return nullptr;
|
|
V = GEP->getPointerOperand();
|
|
} else if (Operator::getOpcode(V) == Instruction::BitCast) {
|
|
V = cast<Operator>(V)->getOperand(0);
|
|
} else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
|
|
if (GA->isInterposable())
|
|
break;
|
|
V = GA->getAliasee();
|
|
} else {
|
|
break;
|
|
}
|
|
assert(V->getType()->isPointerTy() && "Unexpected operand type!");
|
|
} while (Visited.insert(V).second);
|
|
|
|
Type *IntPtrTy = DL.getIntPtrType(V->getContext());
|
|
return cast<ConstantInt>(ConstantInt::get(IntPtrTy, Offset));
|
|
}
|
|
|
|
/// \brief 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) {
|
|
++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
|
|
// by accident as much as because they are principled bonuses.
|
|
//
|
|
// FIXME: It would be nice to remove all such bonuses. At least it would be
|
|
// nice to base the bonus values on something more scientific.
|
|
assert(NumInstructions == 0);
|
|
assert(NumVectorInstructions == 0);
|
|
|
|
// Update the threshold based on callsite properties
|
|
updateThreshold(CS, F);
|
|
|
|
FiftyPercentVectorBonus = 3 * Threshold / 2;
|
|
TenPercentVectorBonus = 3 * Threshold / 4;
|
|
|
|
// Track whether the post-inlining function would have more than one basic
|
|
// block. A single basic block is often intended for inlining. Balloon the
|
|
// threshold by 50% until we pass the single-BB phase.
|
|
bool SingleBB = true;
|
|
int SingleBBBonus = Threshold / 2;
|
|
|
|
// Speculatively apply all possible bonuses to Threshold. If cost exceeds
|
|
// this Threshold any time, and cost cannot decrease, we can stop processing
|
|
// the rest of the function body.
|
|
Threshold += (SingleBBBonus + FiftyPercentVectorBonus);
|
|
|
|
// Give out bonuses for the callsite, as the instructions setting them up
|
|
// will be gone after inlining.
|
|
Cost -= getCallsiteCost(CS, DL);
|
|
|
|
// If there is only one call of the function, and it has internal linkage,
|
|
// the cost of inlining it drops dramatically.
|
|
bool OnlyOneCallAndLocalLinkage =
|
|
F.hasLocalLinkage() && F.hasOneUse() && &F == CS.getCalledFunction();
|
|
if (OnlyOneCallAndLocalLinkage)
|
|
Cost -= InlineConstants::LastCallToStaticBonus;
|
|
|
|
// 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;
|
|
|
|
if (F.empty())
|
|
return true;
|
|
|
|
Function *Caller = CS.getInstruction()->getParent()->getParent();
|
|
// Check if the caller function is recursive itself.
|
|
for (User *U : Caller->users()) {
|
|
CallSite Site(U);
|
|
if (!Site)
|
|
continue;
|
|
Instruction *I = Site.getInstruction();
|
|
if (I->getParent()->getParent() == Caller) {
|
|
IsCallerRecursive = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Populate our simplified values by mapping from function arguments to call
|
|
// arguments with known important simplifications.
|
|
CallSite::arg_iterator CAI = CS.arg_begin();
|
|
for (Function::arg_iterator FAI = F.arg_begin(), FAE = F.arg_end();
|
|
FAI != FAE; ++FAI, ++CAI) {
|
|
assert(CAI != CS.arg_end());
|
|
if (Constant *C = dyn_cast<Constant>(CAI))
|
|
SimplifiedValues[&*FAI] = C;
|
|
|
|
Value *PtrArg = *CAI;
|
|
if (ConstantInt *C = stripAndComputeInBoundsConstantOffsets(PtrArg)) {
|
|
ConstantOffsetPtrs[&*FAI] = std::make_pair(PtrArg, C->getValue());
|
|
|
|
// We can SROA any pointer arguments derived from alloca instructions.
|
|
if (isa<AllocaInst>(PtrArg)) {
|
|
SROAArgValues[&*FAI] = PtrArg;
|
|
SROAArgCosts[PtrArg] = 0;
|
|
}
|
|
}
|
|
}
|
|
NumConstantArgs = SimplifiedValues.size();
|
|
NumConstantOffsetPtrArgs = ConstantOffsetPtrs.size();
|
|
NumAllocaArgs = SROAArgValues.size();
|
|
|
|
// FIXME: If a caller has multiple calls to a callee, we end up recomputing
|
|
// the ephemeral values multiple times (and they're completely determined by
|
|
// the callee, so this is purely duplicate work).
|
|
SmallPtrSet<const Value *, 32> EphValues;
|
|
CodeMetrics::collectEphemeralValues(&F, &GetAssumptionCache(F), EphValues);
|
|
|
|
// The worklist of live basic blocks in the callee *after* inlining. We avoid
|
|
// adding basic blocks of the callee which can be proven to be dead for this
|
|
// particular call site in order to get more accurate cost estimates. This
|
|
// requires a somewhat heavyweight iteration pattern: we need to walk the
|
|
// basic blocks in a breadth-first order as we insert live successors. To
|
|
// accomplish this, prioritizing for small iterations because we exit after
|
|
// crossing our threshold, we use a small-size optimized SetVector.
|
|
typedef SetVector<BasicBlock *, SmallVector<BasicBlock *, 16>,
|
|
SmallPtrSet<BasicBlock *, 16>>
|
|
BBSetVector;
|
|
BBSetVector BBWorklist;
|
|
BBWorklist.insert(&F.getEntryBlock());
|
|
// Note that we *must not* cache the size, this loop grows the worklist.
|
|
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 (Cost > Threshold)
|
|
break;
|
|
|
|
BasicBlock *BB = BBWorklist[Idx];
|
|
if (BB->empty())
|
|
continue;
|
|
|
|
// 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;
|
|
|
|
// 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;
|
|
|
|
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();
|
|
if (ConstantInt *SimpleCond =
|
|
dyn_cast_or_null<ConstantInt>(SimplifiedValues.lookup(Cond))) {
|
|
BBWorklist.insert(BI->getSuccessor(SimpleCond->isZero() ? 1 : 0));
|
|
continue;
|
|
}
|
|
}
|
|
} else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
|
|
Value *Cond = SI->getCondition();
|
|
if (ConstantInt *SimpleCond =
|
|
dyn_cast_or_null<ConstantInt>(SimplifiedValues.lookup(Cond))) {
|
|
BBWorklist.insert(SI->findCaseValue(SimpleCond)->getCaseSuccessor());
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// If we're unable to select a particular successor, just count all of
|
|
// them.
|
|
for (unsigned TIdx = 0, TSize = TI->getNumSuccessors(); TIdx != TSize;
|
|
++TIdx)
|
|
BBWorklist.insert(TI->getSuccessor(TIdx));
|
|
|
|
// If we had any successors at this point, than post-inlining is likely to
|
|
// have them as well. Note that we assume any basic blocks which existed
|
|
// due to branches or switches which folded above will also fold after
|
|
// inlining.
|
|
if (SingleBB && TI->getNumSuccessors() > 1) {
|
|
// Take off the bonus we applied to the threshold.
|
|
Threshold -= SingleBBBonus;
|
|
SingleBB = false;
|
|
}
|
|
}
|
|
|
|
// 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;
|
|
|
|
// 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 -= FiftyPercentVectorBonus;
|
|
else if (NumVectorInstructions <= NumInstructions / 2)
|
|
Threshold -= (FiftyPercentVectorBonus - TenPercentVectorBonus);
|
|
|
|
return Cost < std::max(1, Threshold);
|
|
}
|
|
|
|
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
|
|
/// \brief Dump stats about this call's analysis.
|
|
LLVM_DUMP_METHOD void CallAnalyzer::dump() {
|
|
#define DEBUG_PRINT_STAT(x) dbgs() << " " #x ": " << x << "\n"
|
|
DEBUG_PRINT_STAT(NumConstantArgs);
|
|
DEBUG_PRINT_STAT(NumConstantOffsetPtrArgs);
|
|
DEBUG_PRINT_STAT(NumAllocaArgs);
|
|
DEBUG_PRINT_STAT(NumConstantPtrCmps);
|
|
DEBUG_PRINT_STAT(NumConstantPtrDiffs);
|
|
DEBUG_PRINT_STAT(NumInstructionsSimplified);
|
|
DEBUG_PRINT_STAT(NumInstructions);
|
|
DEBUG_PRINT_STAT(SROACostSavings);
|
|
DEBUG_PRINT_STAT(SROACostSavingsLost);
|
|
DEBUG_PRINT_STAT(ContainsNoDuplicateCall);
|
|
DEBUG_PRINT_STAT(Cost);
|
|
DEBUG_PRINT_STAT(Threshold);
|
|
#undef DEBUG_PRINT_STAT
|
|
}
|
|
#endif
|
|
|
|
/// \brief Test that there are no attribute conflicts between Caller and Callee
|
|
/// that prevent inlining.
|
|
static bool functionsHaveCompatibleAttributes(Function *Caller,
|
|
Function *Callee,
|
|
TargetTransformInfo &TTI) {
|
|
return TTI.areInlineCompatible(Caller, Callee) &&
|
|
AttributeFuncs::areInlineCompatible(*Caller, *Callee);
|
|
}
|
|
|
|
int llvm::getCallsiteCost(CallSite CS, const DataLayout &DL) {
|
|
int Cost = 0;
|
|
for (unsigned I = 0, E = CS.arg_size(); I != E; ++I) {
|
|
if (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 = DL.getTypeSizeInBits(PTy->getElementType());
|
|
unsigned PointerSize = DL.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;
|
|
}
|
|
}
|
|
// The call instruction also disappears after inlining.
|
|
Cost += InlineConstants::InstrCost + InlineConstants::CallPenalty;
|
|
return Cost;
|
|
}
|
|
|
|
InlineCost llvm::getInlineCost(
|
|
CallSite CS, const InlineParams &Params, TargetTransformInfo &CalleeTTI,
|
|
std::function<AssumptionCache &(Function &)> &GetAssumptionCache,
|
|
Optional<function_ref<BlockFrequencyInfo &(Function &)>> GetBFI,
|
|
ProfileSummaryInfo *PSI) {
|
|
return getInlineCost(CS, CS.getCalledFunction(), Params, CalleeTTI,
|
|
GetAssumptionCache, GetBFI, PSI);
|
|
}
|
|
|
|
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) {
|
|
|
|
// Cannot inline indirect calls.
|
|
if (!Callee)
|
|
return llvm::InlineCost::getNever();
|
|
|
|
// 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();
|
|
}
|
|
|
|
// Never inline functions with conflicting attributes (unless callee has
|
|
// always-inline attribute).
|
|
if (!functionsHaveCompatibleAttributes(CS.getCaller(), Callee, CalleeTTI))
|
|
return llvm::InlineCost::getNever();
|
|
|
|
// Don't inline this call if the caller has the optnone attribute.
|
|
if (CS.getCaller()->hasFnAttribute(Attribute::OptimizeNone))
|
|
return llvm::InlineCost::getNever();
|
|
|
|
// 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();
|
|
|
|
DEBUG(llvm::dbgs() << " Analyzing call of " << Callee->getName()
|
|
<< "...\n");
|
|
|
|
CallAnalyzer CA(CalleeTTI, GetAssumptionCache, GetBFI, PSI, *Callee, CS,
|
|
Params);
|
|
bool ShouldInline = CA.analyzeCall(CS);
|
|
|
|
DEBUG(CA.dump());
|
|
|
|
// Check if there was a reason to force inlining or no inlining.
|
|
if (!ShouldInline && CA.getCost() < CA.getThreshold())
|
|
return InlineCost::getNever();
|
|
if (ShouldInline && CA.getCost() >= CA.getThreshold())
|
|
return InlineCost::getAlways();
|
|
|
|
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
|
|
// blockaddresses.
|
|
if (isa<IndirectBrInst>(BI->getTerminator()) || BI->hasAddressTaken())
|
|
return false;
|
|
|
|
for (auto &II : *BI) {
|
|
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;
|
|
|
|
// Disallow inlining functions that call @llvm.localescape. Doing this
|
|
// correctly would require major changes to the inliner.
|
|
if (CS.getCalledFunction() &&
|
|
CS.getCalledFunction()->getIntrinsicID() ==
|
|
llvm::Intrinsic::localescape)
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
// APIs to create InlineParams based on command line flags and/or other
|
|
// parameters.
|
|
|
|
InlineParams llvm::getInlineParams(int Threshold) {
|
|
InlineParams Params;
|
|
|
|
// This field is the threshold to use for a callee by default. This is
|
|
// derived from one or more of:
|
|
// * optimization or size-optimization levels,
|
|
// * a value passed to createFunctionInliningPass function, or
|
|
// * the -inline-threshold flag.
|
|
// If the -inline-threshold flag is explicitly specified, that is used
|
|
// irrespective of anything else.
|
|
if (InlineThreshold.getNumOccurrences() > 0)
|
|
Params.DefaultThreshold = InlineThreshold;
|
|
else
|
|
Params.DefaultThreshold = Threshold;
|
|
|
|
// Set the HintThreshold knob from the -inlinehint-threshold.
|
|
Params.HintThreshold = HintThreshold;
|
|
|
|
// Set the HotCallSiteThreshold knob from the -hot-callsite-threshold.
|
|
Params.HotCallSiteThreshold = HotCallSiteThreshold;
|
|
|
|
// Set the ColdCallSiteThreshold knob from the -inline-cold-callsite-threshold.
|
|
Params.ColdCallSiteThreshold = ColdCallSiteThreshold;
|
|
|
|
// Set the OptMinSizeThreshold and OptSizeThreshold params only if the
|
|
// -inlinehint-threshold commandline option is not explicitly given. If that
|
|
// option is present, then its value applies even for callees with size and
|
|
// minsize attributes.
|
|
// If the -inline-threshold is not specified, set the ColdThreshold from the
|
|
// -inlinecold-threshold even if it is not explicitly passed. If
|
|
// -inline-threshold is specified, then -inlinecold-threshold needs to be
|
|
// explicitly specified to set the ColdThreshold knob
|
|
if (InlineThreshold.getNumOccurrences() == 0) {
|
|
Params.OptMinSizeThreshold = InlineConstants::OptMinSizeThreshold;
|
|
Params.OptSizeThreshold = InlineConstants::OptSizeThreshold;
|
|
Params.ColdThreshold = ColdThreshold;
|
|
} else if (ColdThreshold.getNumOccurrences() > 0) {
|
|
Params.ColdThreshold = ColdThreshold;
|
|
}
|
|
return Params;
|
|
}
|
|
|
|
InlineParams llvm::getInlineParams() {
|
|
return getInlineParams(InlineThreshold);
|
|
}
|
|
|
|
// Compute the default threshold for inlining based on the opt level and the
|
|
// size opt level.
|
|
static int computeThresholdFromOptLevels(unsigned OptLevel,
|
|
unsigned SizeOptLevel) {
|
|
if (OptLevel > 2)
|
|
return InlineConstants::OptAggressiveThreshold;
|
|
if (SizeOptLevel == 1) // -Os
|
|
return InlineConstants::OptSizeThreshold;
|
|
if (SizeOptLevel == 2) // -Oz
|
|
return InlineConstants::OptMinSizeThreshold;
|
|
return InlineThreshold;
|
|
}
|
|
|
|
InlineParams llvm::getInlineParams(unsigned OptLevel, unsigned SizeOptLevel) {
|
|
return getInlineParams(computeThresholdFromOptLevels(OptLevel, SizeOptLevel));
|
|
}
|