llvm-project/llvm/lib/Analysis/BlockFrequency.cpp

60 lines
2.0 KiB
C++

//=======-------- BlockFrequency.cpp - Block Frequency Analysis -------=======//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Loops should be simplified before this analysis.
//
//===----------------------------------------------------------------------===//
#include "llvm/InitializePasses.h"
#include "llvm/Analysis/BlockFrequencyImpl.h"
#include "llvm/Analysis/BlockFrequency.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
using namespace llvm;
INITIALIZE_PASS_BEGIN(BlockFrequency, "block-freq", "Block Frequency Analysis",
true, true)
INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfo)
INITIALIZE_PASS_END(BlockFrequency, "block-freq", "Block Frequency Analysis",
true, true)
char BlockFrequency::ID = 0;
BlockFrequency::BlockFrequency() : FunctionPass(ID) {
initializeBlockFrequencyPass(*PassRegistry::getPassRegistry());
BFI = new BlockFrequencyImpl<BasicBlock, Function, BranchProbabilityInfo>();
}
BlockFrequency::~BlockFrequency() {
delete BFI;
}
void BlockFrequency::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<BranchProbabilityInfo>();
AU.setPreservesAll();
}
bool BlockFrequency::runOnFunction(Function &F) {
BranchProbabilityInfo &BPI = getAnalysis<BranchProbabilityInfo>();
BFI->doFunction(&F, &BPI);
return false;
}
/// getblockFreq - Return block frequency. Never return 0, value must be
/// positive. Please note that initial frequency is equal to 1024. It means that
/// we should not rely on the value itself, but only on the comparison to the
/// other block frequencies. We do this to avoid using of floating points.
///
uint32_t BlockFrequency::getBlockFreq(BasicBlock *BB) {
return BFI->getBlockFreq(BB);
}