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Refactor code-size reduction estimation methods out of InlineCostAnalyzer and into CodeMetrics. They

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don't use any InlineCostAnalyzer state, and are useful for other clients who don't necessarily want to use
all of InlineCostAnalyzer's logic, some of which is fairly inlining-specific.

No intended functionality change.

llvm-svn: 113499
This commit is contained in:
Owen Anderson 2010-09-09 16:56:42 +00:00
parent 8c7fe0e9d0
commit 9a194c80c4
3 changed files with 101 additions and 101 deletions
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11
include/llvm/Analysis/CodeMetrics.h
View File

@ -66,6 +66,17 @@ namespace llvm {
/// analyzeFunction - Add information about the specified function
/// to the current structure.
void analyzeFunction(Function *F);
/// CountCodeReductionForConstant - Figure out an approximation for how
/// many instructions will be constant folded if the specified value is
/// constant.
unsigned CountCodeReductionForConstant(Value *V);
/// CountCodeReductionForAlloca - Figure out an approximation of how much
/// smaller the function will be if it is inlined into a context where an
/// argument becomes an alloca.
///
unsigned CountCodeReductionForAlloca(Value *V);
};
}

9
include/llvm/Analysis/InlineCost.h
View File

@ -110,16 +110,7 @@ namespace llvm {
/// entry here.
std::vector<ArgInfo> ArgumentWeights;
/// CountCodeReductionForConstant - Figure out an approximation for how
/// many instructions will be constant folded if the specified value is
/// constant.
unsigned CountCodeReductionForConstant(Value *V);
/// CountCodeReductionForAlloca - Figure out an approximation of how much
/// smaller the function will be if it is inlined into a context where an
/// argument becomes an alloca.
///
unsigned CountCodeReductionForAlloca(Value *V);
/// analyzeFunction - Add information about the specified function
/// to the current structure.

182
lib/Analysis/InlineCost.cpp
View File

@ -18,96 +18,6 @@
#include "llvm/ADT/SmallPtrSet.h"
using namespace llvm;
// CountCodeReductionForConstant - Figure out an approximation for how many
// instructions will be constant folded if the specified value is constant.
//
unsigned InlineCostAnalyzer::FunctionInfo::
CountCodeReductionForConstant(Value *V) {
unsigned Reduction = 0;
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
User *U = *UI;
if (isa<BranchInst>(U) || isa<SwitchInst>(U)) {
// We will be able to eliminate all but one of the successors.
const TerminatorInst &TI = cast<TerminatorInst>(*U);
const unsigned NumSucc = TI.getNumSuccessors();
unsigned Instrs = 0;
for (unsigned I = 0; I != NumSucc; ++I)
Instrs += Metrics.NumBBInsts[TI.getSuccessor(I)];
// We don't know which blocks will be eliminated, so use the average size.
Reduction += InlineConstants::InstrCost*Instrs*(NumSucc-1)/NumSucc;
} else if (CallInst *CI = dyn_cast<CallInst>(U)) {
// Turning an indirect call into a direct call is a BIG win
if (CI->getCalledValue() == V)
Reduction += InlineConstants::IndirectCallBonus;
} else if (InvokeInst *II = dyn_cast<InvokeInst>(U)) {
// Turning an indirect call into a direct call is a BIG win
if (II->getCalledValue() == V)
Reduction += InlineConstants::IndirectCallBonus;
} else {
// Figure out if this instruction will be removed due to simple constant
// propagation.
Instruction &Inst = cast<Instruction>(*U);
// We can't constant propagate instructions which have effects or
// read memory.
//
// FIXME: It would be nice to capture the fact that a load from a
// pointer-to-constant-global is actually a *really* good thing to zap.
// Unfortunately, we don't know the pointer that may get propagated here,
// so we can't make this decision.
if (Inst.mayReadFromMemory() || Inst.mayHaveSideEffects() ||
isa<AllocaInst>(Inst))
continue;
bool AllOperandsConstant = true;
for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i)
if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) {
AllOperandsConstant = false;
break;
}
if (AllOperandsConstant) {
// We will get to remove this instruction...
Reduction += InlineConstants::InstrCost;
// And any other instructions that use it which become constants
// themselves.
Reduction += CountCodeReductionForConstant(&Inst);
}
}
}
return Reduction;
}
// CountCodeReductionForAlloca - Figure out an approximation of how much smaller
// the function will be if it is inlined into a context where an argument
// becomes an alloca.
//
unsigned InlineCostAnalyzer::FunctionInfo::
CountCodeReductionForAlloca(Value *V) {
if (!V->getType()->isPointerTy()) return 0; // Not a pointer
unsigned Reduction = 0;
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
Instruction *I = cast<Instruction>(*UI);
if (isa<LoadInst>(I) || isa<StoreInst>(I))
Reduction += InlineConstants::InstrCost;
else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) {
// If the GEP has variable indices, we won't be able to do much with it.
if (GEP->hasAllConstantIndices())
Reduction += CountCodeReductionForAlloca(GEP);
} else if (BitCastInst *BCI = dyn_cast<BitCastInst>(I)) {
// Track pointer through bitcasts.
Reduction += CountCodeReductionForAlloca(BCI);
} else {
// If there is some other strange instruction, we're not going to be able
// to do much if we inline this.
return 0;
}
}
return Reduction;
}
/// callIsSmall - If a call is likely to lower to a single target instruction,
/// or is otherwise deemed small return true.
/// TODO: Perhaps calls like memcpy, strcpy, etc?
@ -226,6 +136,94 @@ void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB) {
NumBBInsts[BB] = NumInsts - NumInstsBeforeThisBB;
}
// CountCodeReductionForConstant - Figure out an approximation for how many
// instructions will be constant folded if the specified value is constant.
//
unsigned CodeMetrics::CountCodeReductionForConstant(Value *V) {
unsigned Reduction = 0;
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
User *U = *UI;
if (isa<BranchInst>(U) || isa<SwitchInst>(U)) {
// We will be able to eliminate all but one of the successors.
const TerminatorInst &TI = cast<TerminatorInst>(*U);
const unsigned NumSucc = TI.getNumSuccessors();
unsigned Instrs = 0;
for (unsigned I = 0; I != NumSucc; ++I)
Instrs += NumBBInsts[TI.getSuccessor(I)];
// We don't know which blocks will be eliminated, so use the average size.
Reduction += InlineConstants::InstrCost*Instrs*(NumSucc-1)/NumSucc;
} else if (CallInst *CI = dyn_cast<CallInst>(U)) {
// Turning an indirect call into a direct call is a BIG win
if (CI->getCalledValue() == V)
Reduction += InlineConstants::IndirectCallBonus;
} else if (InvokeInst *II = dyn_cast<InvokeInst>(U)) {
// Turning an indirect call into a direct call is a BIG win
if (II->getCalledValue() == V)
Reduction += InlineConstants::IndirectCallBonus;
} else {
// Figure out if this instruction will be removed due to simple constant
// propagation.
Instruction &Inst = cast<Instruction>(*U);
// We can't constant propagate instructions which have effects or
// read memory.
//
// FIXME: It would be nice to capture the fact that a load from a
// pointer-to-constant-global is actually a *really* good thing to zap.
// Unfortunately, we don't know the pointer that may get propagated here,
// so we can't make this decision.
if (Inst.mayReadFromMemory() || Inst.mayHaveSideEffects() ||
isa<AllocaInst>(Inst))
continue;
bool AllOperandsConstant = true;
for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i)
if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) {
AllOperandsConstant = false;
break;
}
if (AllOperandsConstant) {
// We will get to remove this instruction...
Reduction += InlineConstants::InstrCost;
// And any other instructions that use it which become constants
// themselves.
Reduction += CountCodeReductionForConstant(&Inst);
}
}
}
return Reduction;
}
// CountCodeReductionForAlloca - Figure out an approximation of how much smaller
// the function will be if it is inlined into a context where an argument
// becomes an alloca.
//
unsigned CodeMetrics::CountCodeReductionForAlloca(Value *V) {
if (!V->getType()->isPointerTy()) return 0; // Not a pointer
unsigned Reduction = 0;
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
Instruction *I = cast<Instruction>(*UI);
if (isa<LoadInst>(I) || isa<StoreInst>(I))
Reduction += InlineConstants::InstrCost;
else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) {
// If the GEP has variable indices, we won't be able to do much with it.
if (GEP->hasAllConstantIndices())
Reduction += CountCodeReductionForAlloca(GEP);
} else if (BitCastInst *BCI = dyn_cast<BitCastInst>(I)) {
// Track pointer through bitcasts.
Reduction += CountCodeReductionForAlloca(BCI);
} else {
// If there is some other strange instruction, we're not going to be able
// to do much if we inline this.
return 0;
}
}
return Reduction;
}
/// analyzeFunction - Fill in the current structure with information gleaned
/// from the specified function.
void CodeMetrics::analyzeFunction(Function *F) {
@ -254,8 +252,8 @@ void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F) {
// code can be eliminated if one of the arguments is a constant.
ArgumentWeights.reserve(F->arg_size());
for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I)
ArgumentWeights.push_back(ArgInfo(CountCodeReductionForConstant(I),
CountCodeReductionForAlloca(I)));
ArgumentWeights.push_back(ArgInfo(Metrics.CountCodeReductionForConstant(I),
Metrics.CountCodeReductionForAlloca(I)));
}
/// NeverInline - returns true if the function should never be inlined into