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 bottom-up inlining of functions into callees.
12 //===----------------------------------------------------------------------===//
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 // NumInsts, NumBlocks - Keep track of how large each function is, which is
42 // used to estimate the code size cost of inlining it.
43 unsigned NumInsts, NumBlocks;
45 // NumVectorInsts - Keep track how many instrctions produce vector values.
46 // The inliner is being more aggressive with inlining vector kernels.
47 unsigned NumVectorInsts;
49 // ArgumentWeights - Each formal argument of the function is inspected to
50 // see if it is used in any contexts where making it a constant or alloca
51 // would reduce the code size. If so, we add some value to the argument
53 std::vector<ArgInfo> ArgumentWeights;
55 FunctionInfo() : NumInsts(0), NumBlocks(0), NumVectorInsts(0) {}
57 /// analyzeFunction - Fill in the current structure with information gleaned
58 /// from the specified function.
59 void analyzeFunction(Function *F);
61 // CountCodeReductionForConstant - Figure out an approximation for how many
62 // instructions will be constant folded if the specified value is constant.
64 unsigned CountCodeReductionForConstant(Value *V);
66 // CountCodeReductionForAlloca - Figure out an approximation of how much smaller
67 // the function will be if it is inlined into a context where an argument
70 unsigned CountCodeReductionForAlloca(Value *V);
73 std::map<const Function *, FunctionInfo>CachedFunctionInfo;
77 // getInlineCost - The heuristic used to determine if we should inline the
78 // function call or not.
80 int getInlineCost(CallSite CS,
81 SmallPtrSet<const Function *, 16> &NeverInline);
83 // getInlineFudgeFactor - Return a > 1.0 factor if the inliner should use a
84 // higher threshold to determine if the function call should be inlined.
85 float getInlineFudgeFactor(CallSite CS);