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author | Andrew Trick <atrick@apple.com> | 2011-06-11 01:05:22 +0000 |
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committer | Andrew Trick <atrick@apple.com> | 2011-06-11 01:05:22 +0000 |
commit | f289df2d9544bd3a0934651daa20e589544413ba (patch) | |
tree | 7301c85f67fa32083f0ffbfd7908bc79002bd0bd /include/llvm | |
parent | b5923db192d2aa938ff3c12aaac87d80ab649625 (diff) | |
download | llvm-f289df2d9544bd3a0934651daa20e589544413ba.tar.gz llvm-f289df2d9544bd3a0934651daa20e589544413ba.tar.bz2 llvm-f289df2d9544bd3a0934651daa20e589544413ba.tar.xz |
Branch profiling: floating-point avoidance.
Patch by: Jakub Staszak!
Introduces BranchProbability. Changes unsigned to uint32_t all over and
uint64_t only when overflow is expected.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132867 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'include/llvm')
-rw-r--r-- | include/llvm/Analysis/BranchProbabilityInfo.h | 26 | ||||
-rw-r--r-- | include/llvm/Support/BranchProbability.h | 50 |
2 files changed, 68 insertions, 8 deletions
diff --git a/include/llvm/Analysis/BranchProbabilityInfo.h b/include/llvm/Analysis/BranchProbabilityInfo.h index bf2a6a765f..91f289da7c 100644 --- a/include/llvm/Analysis/BranchProbabilityInfo.h +++ b/include/llvm/Analysis/BranchProbabilityInfo.h @@ -15,19 +15,24 @@ #define LLVM_ANALYSIS_BRANCHPROBABILITYINFO_H #include "llvm/InitializePasses.h" +#include "llvm/Support/BranchProbability.h" #include "llvm/Analysis/LoopInfo.h" -#include "llvm/Support/Debug.h" namespace llvm { +class raw_ostream; + class BranchProbabilityInfo : public FunctionPass { // Default weight value. Used when we don't have information about the edge. - static const unsigned int DEFAULT_WEIGHT = 16; + static const uint32_t DEFAULT_WEIGHT = 16; typedef std::pair<BasicBlock *, BasicBlock *> Edge; - DenseMap<Edge, unsigned> Weights; + DenseMap<Edge, uint32_t> Weights; + + // Get sum of the block successors' weights. + uint32_t getSumForBlock(BasicBlock *BB) const; public: static char ID; @@ -43,12 +48,12 @@ public: bool runOnFunction(Function &F); - // Returned value is between 1 and UINT_MAX. Look at BranchProbabilityInfo.cpp - // for details. - unsigned getEdgeWeight(BasicBlock *Src, BasicBlock *Dst) const; + // Returned value is between 1 and UINT32_MAX. Look at + // BranchProbabilityInfo.cpp for details. + uint32_t getEdgeWeight(BasicBlock *Src, BasicBlock *Dst) const; // Look at BranchProbabilityInfo.cpp for details. Use it with caution! - void setEdgeWeight(BasicBlock *Src, BasicBlock *Dst, unsigned Weight); + void setEdgeWeight(BasicBlock *Src, BasicBlock *Dst, uint32_t Weight); // A 'Hot' edge is an edge which probability is >= 80%. bool isEdgeHot(BasicBlock *Src, BasicBlock *Dst) const; @@ -56,11 +61,16 @@ public: // Return a hot successor for the block BB or null if there isn't one. BasicBlock *getHotSucc(BasicBlock *BB) const; + // Return a probability as a fraction between 0 (0% probability) and + // 1 (100% probability), however the value is never equal to 0, and can be 1 + // only iff SRC block has only one successor. + BranchProbability getEdgeProbability(BasicBlock *Src, BasicBlock *Dst) const; + // Print value between 0 (0% probability) and 1 (100% probability), // however the value is never equal to 0, and can be 1 only iff SRC block // has only one successor. raw_ostream &printEdgeProbability(raw_ostream &OS, BasicBlock *Src, - BasicBlock *Dst) const; + BasicBlock *Dst) const; }; } diff --git a/include/llvm/Support/BranchProbability.h b/include/llvm/Support/BranchProbability.h new file mode 100644 index 0000000000..7ba649133b --- /dev/null +++ b/include/llvm/Support/BranchProbability.h @@ -0,0 +1,50 @@ +//===- BranchProbability.h - Branch Probability Analysis --------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// Definition of BranchProbability shared by IR and Machine Instructions. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_SUPPORT_BRANCHPROBABILITY_H +#define LLVM_SUPPORT_BRANCHPROBABILITY_H + +#include "llvm/Support/DataTypes.h" + +namespace llvm { + +class raw_ostream; +class BranchProbabilityInfo; +class MachineBranchProbabilityInfo; +class MachineBasicBlock; + +// This class represents Branch Probability as a non-negative fraction. +class BranchProbability { + friend class BranchProbabilityInfo; + friend class MachineBranchProbabilityInfo; + friend class MachineBasicBlock; + + // Numerator + uint32_t N; + + // Denominator + uint32_t D; + + BranchProbability(uint32_t n, uint32_t d); + +public: + raw_ostream &print(raw_ostream &OS) const; + + void dump() const; +}; + +raw_ostream &operator<<(raw_ostream &OS, const BranchProbability &Prob); + +} + +#endif |