forked from OSchip/llvm-project
[NFC][InlineCost] cleanup - comments, overflow handling.
Reviewed By: apilipenko Tags: #llvm Differential Revision: https://reviews.llvm.org/D60751 llvm-svn: 359609
This commit is contained in:
Fedor Sergeev
parent
07ab4e7db8
commit
eeae45dc77
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@ -125,26 +125,38 @@ class CallAnalyzer : public InstVisitor<CallAnalyzer, bool> {
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/// Tunable parameters that control the analysis.
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const InlineParams &Params;
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/// Upper bound for the inlining cost. Bonuses are being applied to account
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/// for speculative "expected profit" of the inlining decision.
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int Threshold;
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int Cost;
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/// Inlining cost measured in abstract units, accounts for all the
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/// instructions expected to be executed for a given function invocation.
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/// Instructions that are statically proven to be dead based on call-site
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/// arguments are not counted here.
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int Cost = 0;
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bool ComputeFullInlineCost;
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bool IsCallerRecursive;
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bool IsRecursiveCall;
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bool ExposesReturnsTwice;
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bool HasDynamicAlloca;
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bool ContainsNoDuplicateCall;
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bool HasReturn;
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bool HasIndirectBr;
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bool HasUninlineableIntrinsic;
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bool InitsVargArgs;
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bool IsCallerRecursive = false;
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bool IsRecursiveCall = false;
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bool ExposesReturnsTwice = false;
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bool HasDynamicAlloca = false;
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bool ContainsNoDuplicateCall = false;
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bool HasReturn = false;
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bool HasIndirectBr = false;
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bool HasUninlineableIntrinsic = false;
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bool InitsVargArgs = false;
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/// Number of bytes allocated statically by the callee.
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uint64_t AllocatedSize;
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unsigned NumInstructions, NumVectorInstructions;
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int VectorBonus, TenPercentVectorBonus;
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// Bonus to be applied when the callee has only one reachable basic block.
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int SingleBBBonus;
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uint64_t AllocatedSize = 0;
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unsigned NumInstructions = 0;
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unsigned NumVectorInstructions = 0;
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/// Bonus to be applied when percentage of vector instructions in callee is
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/// high (see more details in updateThreshold).
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int VectorBonus = 0;
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/// Bonus to be applied when the callee has only one reachable basic block.
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int SingleBBBonus = 0;
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/// While we walk the potentially-inlined instructions, we build up and
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/// maintain a mapping of simplified values specific to this callsite. The
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@ -179,7 +191,7 @@ class CallAnalyzer : public InstVisitor<CallAnalyzer, bool> {
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/// loads.
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bool EnableLoadElimination;
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SmallPtrSet<Value *, 16> LoadAddrSet;
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int LoadEliminationCost;
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int LoadEliminationCost = 0;
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// Custom simplification helper routines.
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bool isAllocaDerivedArg(Value *V);
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@ -230,6 +242,12 @@ class CallAnalyzer : public InstVisitor<CallAnalyzer, bool> {
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InlineResult analyzeBlock(BasicBlock *BB,
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SmallPtrSetImpl<const Value *> &EphValues);
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/// Handle a capped 'int' increment for Cost.
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void addCost(int64_t Inc, int64_t UpperBound = INT_MAX) {
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assert(UpperBound > 0 && UpperBound <= INT_MAX && "invalid upper bound");
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Cost = (int)std::min(UpperBound, Cost + Inc);
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}
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// Disable several entry points to the visitor so we don't accidentally use
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// them by declaring but not defining them here.
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void visit(Module *);
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@ -278,18 +296,9 @@ public:
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: TTI(TTI), GetAssumptionCache(GetAssumptionCache), GetBFI(GetBFI),
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PSI(PSI), F(Callee), DL(F.getParent()->getDataLayout()), ORE(ORE),
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CandidateCall(Call), Params(Params), Threshold(Params.DefaultThreshold),
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Cost(0), ComputeFullInlineCost(OptComputeFullInlineCost ||
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Params.ComputeFullInlineCost || ORE),
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IsCallerRecursive(false), IsRecursiveCall(false),
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ExposesReturnsTwice(false), HasDynamicAlloca(false),
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ContainsNoDuplicateCall(false), HasReturn(false), HasIndirectBr(false),
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HasUninlineableIntrinsic(false), InitsVargArgs(false), AllocatedSize(0),
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NumInstructions(0), NumVectorInstructions(0), VectorBonus(0),
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SingleBBBonus(0), EnableLoadElimination(true), LoadEliminationCost(0),
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NumConstantArgs(0), NumConstantOffsetPtrArgs(0), NumAllocaArgs(0),
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NumConstantPtrCmps(0), NumConstantPtrDiffs(0),
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NumInstructionsSimplified(0), SROACostSavings(0),
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SROACostSavingsLost(0) {}
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ComputeFullInlineCost(OptComputeFullInlineCost ||
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Params.ComputeFullInlineCost || ORE),
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EnableLoadElimination(true) {}
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InlineResult analyzeCall(CallBase &Call);
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@ -298,14 +307,14 @@ public:
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// Keep a bunch of stats about the cost savings found so we can print them
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// out when debugging.
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unsigned NumConstantArgs;
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unsigned NumConstantOffsetPtrArgs;
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unsigned NumAllocaArgs;
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unsigned NumConstantPtrCmps;
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unsigned NumConstantPtrDiffs;
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unsigned NumInstructionsSimplified;
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unsigned SROACostSavings;
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unsigned SROACostSavingsLost;
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unsigned NumConstantArgs = 0;
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unsigned NumConstantOffsetPtrArgs = 0;
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unsigned NumAllocaArgs = 0;
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unsigned NumConstantPtrCmps = 0;
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unsigned NumConstantPtrDiffs = 0;
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unsigned NumInstructionsSimplified = 0;
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unsigned SROACostSavings = 0;
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unsigned SROACostSavingsLost = 0;
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void dump();
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};
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@ -340,7 +349,7 @@ bool CallAnalyzer::lookupSROAArgAndCost(
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void CallAnalyzer::disableSROA(DenseMap<Value *, int>::iterator CostIt) {
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// If we're no longer able to perform SROA we need to undo its cost savings
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// and prevent subsequent analysis.
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Cost += CostIt->second;
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addCost(CostIt->second);
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SROACostSavings -= CostIt->second;
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SROACostSavingsLost += CostIt->second;
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SROAArgCosts.erase(CostIt);
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@ -364,7 +373,7 @@ void CallAnalyzer::accumulateSROACost(DenseMap<Value *, int>::iterator CostIt,
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void CallAnalyzer::disableLoadElimination() {
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if (EnableLoadElimination) {
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Cost += LoadEliminationCost;
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addCost(LoadEliminationCost);
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LoadEliminationCost = 0;
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EnableLoadElimination = false;
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}
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@ -719,7 +728,7 @@ bool CallAnalyzer::visitCastInst(CastInst &I) {
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case Instruction::FPToUI:
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case Instruction::FPToSI:
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if (TTI.getFPOpCost(I.getType()) == TargetTransformInfo::TCC_Expensive)
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Cost += InlineConstants::CallPenalty;
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addCost(InlineConstants::CallPenalty);
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break;
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default:
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break;
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@ -1089,7 +1098,7 @@ bool CallAnalyzer::visitBinaryOperator(BinaryOperator &I) {
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// as such.
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if (I.getType()->isFloatingPointTy() &&
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TTI.getFPOpCost(I.getType()) == TargetTransformInfo::TCC_Expensive)
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Cost += InlineConstants::CallPenalty;
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addCost(InlineConstants::CallPenalty);
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return false;
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}
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@ -1226,7 +1235,7 @@ bool CallAnalyzer::visitCallBase(CallBase &Call) {
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case Intrinsic::load_relative:
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// This is normally lowered to 4 LLVM instructions.
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Cost += 3 * InlineConstants::InstrCost;
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addCost(3 * InlineConstants::InstrCost);
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return false;
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case Intrinsic::memset:
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@ -1255,12 +1264,12 @@ bool CallAnalyzer::visitCallBase(CallBase &Call) {
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if (TTI.isLoweredToCall(F)) {
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// We account for the average 1 instruction per call argument setup
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// here.
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Cost += Call.arg_size() * InlineConstants::InstrCost;
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addCost(Call.arg_size() * InlineConstants::InstrCost);
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// Everything other than inline ASM will also have a significant cost
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// merely from making the call.
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if (!isa<InlineAsm>(Call.getCalledValue()))
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Cost += InlineConstants::CallPenalty;
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addCost(InlineConstants::CallPenalty);
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}
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if (!Call.onlyReadsMemory())
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@ -1274,7 +1283,7 @@ bool CallAnalyzer::visitCallBase(CallBase &Call) {
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// First, pay the price of the argument setup. We account for the average
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// 1 instruction per call argument setup here.
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Cost += Call.arg_size() * InlineConstants::InstrCost;
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addCost(Call.arg_size() * InlineConstants::InstrCost);
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// Next, check if this happens to be an indirect function call to a known
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// function in this inline context. If not, we've done all we can.
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@ -1436,7 +1445,7 @@ bool CallAnalyzer::visitSwitchInst(SwitchInst &SI) {
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(int64_t)SI.getNumCases() * InlineConstants::InstrCost + Cost);
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if (CostLowerBound > Threshold && !ComputeFullInlineCost) {
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Cost = CostLowerBound;
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addCost((int64_t)SI.getNumCases() * InlineConstants::InstrCost);
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return false;
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}
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@ -1450,7 +1459,7 @@ bool CallAnalyzer::visitSwitchInst(SwitchInst &SI) {
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int64_t JTCost = (int64_t)JumpTableSize * InlineConstants::InstrCost +
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4 * InlineConstants::InstrCost;
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Cost = std::min((int64_t)CostUpperBound, JTCost + Cost);
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addCost(JTCost, (int64_t)CostUpperBound);
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return false;
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}
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@ -1471,7 +1480,7 @@ bool CallAnalyzer::visitSwitchInst(SwitchInst &SI) {
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// n + n / 2 - 1 = n * 3 / 2 - 1
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if (NumCaseCluster <= 3) {
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// Suppose a comparison includes one compare and one conditional branch.
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Cost += NumCaseCluster * 2 * InlineConstants::InstrCost;
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addCost(NumCaseCluster * 2 * InlineConstants::InstrCost);
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return false;
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}
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@ -1479,7 +1488,7 @@ bool CallAnalyzer::visitSwitchInst(SwitchInst &SI) {
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int64_t SwitchCost =
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ExpectedNumberOfCompare * 2 * InlineConstants::InstrCost;
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Cost = std::min((int64_t)CostUpperBound, SwitchCost + Cost);
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addCost(SwitchCost, (int64_t)CostUpperBound);
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return false;
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}
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@ -1572,7 +1581,7 @@ CallAnalyzer::analyzeBlock(BasicBlock *BB,
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if (Base::visit(&*I))
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++NumInstructionsSimplified;
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else
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Cost += InlineConstants::InstrCost;
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addCost(InlineConstants::InstrCost);
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using namespace ore;
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// If the visit this instruction detected an uninlinable pattern, abort.
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@ -1617,7 +1626,7 @@ CallAnalyzer::analyzeBlock(BasicBlock *BB,
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return IR;
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}
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// Check if we've past the maximum possible threshold so we don't spin in
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// Check if we've passed the maximum possible threshold so we don't spin in
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// huge basic blocks that will never inline.
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if (Cost >= Threshold && !ComputeFullInlineCost)
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return false;
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@ -1743,7 +1752,7 @@ InlineResult CallAnalyzer::analyzeCall(CallBase &Call) {
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// Give out bonuses for the callsite, as the instructions setting them up
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// will be gone after inlining.
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Cost -= getCallsiteCost(Call, DL);
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addCost(-getCallsiteCost(Call, DL));
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// If this function uses the coldcc calling convention, prefer not to inline
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// it.
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@ -1904,7 +1913,7 @@ InlineResult CallAnalyzer::analyzeCall(CallBase &Call) {
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continue;
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NumLoops++;
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}
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Cost += NumLoops * InlineConstants::CallPenalty;
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addCost(NumLoops * InlineConstants::CallPenalty);
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}
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// We applied the maximum possible vector bonus at the beginning. Now,
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