1 //===- InlineCost.cpp - Cost analysis for inliner ---------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements heuristics for inlining decisions.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_TRANSFORMS_UTILS_INLINECOST_H
15 #define LLVM_TRANSFORMS_UTILS_INLINECOST_H
17 #include "llvm/ADT/SmallPtrSet.h"
27 /// InlineCostAnalyzer - Cost analyzer used by inliner.
28 class InlineCostAnalyzer {
31 unsigned ConstantWeight;
32 unsigned AllocaWeight;
34 ArgInfo(unsigned CWeight, unsigned AWeight)
35 : ConstantWeight(CWeight), AllocaWeight(AWeight) {}
38 // FunctionInfo - For each function, calculate the size of it in blocks and
41 /// NeverInline - True if this callee should never be inlined into a
45 /// NumInsts, NumBlocks - Keep track of how large each function is, which
46 /// is used to estimate the code size cost of inlining it.
47 unsigned NumInsts, NumBlocks;
49 /// NumVectorInsts - Keep track of how many instructions produce vector
50 /// values. The inliner is being more aggressive with inlining vector
52 unsigned NumVectorInsts;
54 /// ArgumentWeights - Each formal argument of the function is inspected to
55 /// see if it is used in any contexts where making it a constant or alloca
56 /// would reduce the code size. If so, we add some value to the argument
58 std::vector<ArgInfo> ArgumentWeights;
60 FunctionInfo() : NeverInline(false), NumInsts(0), NumBlocks(0),
63 /// analyzeFunction - Fill in the current structure with information
64 /// gleaned from the specified function.
65 void analyzeFunction(Function *F);
67 /// CountCodeReductionForConstant - Figure out an approximation for how
68 /// many instructions will be constant folded if the specified value is
70 unsigned CountCodeReductionForConstant(Value *V);
72 /// CountCodeReductionForAlloca - Figure out an approximation of how much
73 /// smaller the function will be if it is inlined into a context where an
74 /// argument becomes an alloca.
76 unsigned CountCodeReductionForAlloca(Value *V);
79 std::map<const Function *, FunctionInfo> CachedFunctionInfo;
83 /// getInlineCost - The heuristic used to determine if we should inline the
84 /// function call or not.
86 int getInlineCost(CallSite CS,
87 SmallPtrSet<const Function *, 16> &NeverInline);
89 /// getInlineFudgeFactor - Return a > 1.0 factor if the inliner should use a
90 /// higher threshold to determine if the function call should be inlined.
91 float getInlineFudgeFactor(CallSite CS);