#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/IR/CFG.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Metadata.h"
-#include "llvm/Support/CFG.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
+#define DEBUG_TYPE "branch-prob"
+
INITIALIZE_PASS_BEGIN(BranchProbabilityInfo, "branch-prob",
"Branch Probability Analysis", false, true)
-INITIALIZE_PASS_DEPENDENCY(LoopInfo)
+INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
INITIALIZE_PASS_END(BranchProbabilityInfo, "branch-prob",
"Branch Probability Analysis", false, true)
uint32_t UnreachableWeight =
std::max(UR_TAKEN_WEIGHT / (unsigned)UnreachableEdges.size(), MIN_WEIGHT);
- for (SmallVector<unsigned, 4>::iterator I = UnreachableEdges.begin(),
- E = UnreachableEdges.end();
+ for (SmallVectorImpl<unsigned>::iterator I = UnreachableEdges.begin(),
+ E = UnreachableEdges.end();
I != E; ++I)
setEdgeWeight(BB, *I, UnreachableWeight);
uint32_t ReachableWeight =
std::max(UR_NONTAKEN_WEIGHT / (unsigned)ReachableEdges.size(),
NORMAL_WEIGHT);
- for (SmallVector<unsigned, 4>::iterator I = ReachableEdges.begin(),
- E = ReachableEdges.end();
+ for (SmallVectorImpl<unsigned>::iterator I = ReachableEdges.begin(),
+ E = ReachableEdges.end();
I != E; ++I)
setEdgeWeight(BB, *I, ReachableWeight);
SmallVector<uint32_t, 2> Weights;
Weights.reserve(TI->getNumSuccessors());
for (unsigned i = 1, e = WeightsNode->getNumOperands(); i != e; ++i) {
- ConstantInt *Weight = dyn_cast<ConstantInt>(WeightsNode->getOperand(i));
+ ConstantInt *Weight =
+ mdconst::dyn_extract<ConstantInt>(WeightsNode->getOperand(i));
if (!Weight)
return false;
Weights.push_back(
uint32_t ColdWeight =
std::max(CC_TAKEN_WEIGHT / (unsigned) ColdEdges.size(), MIN_WEIGHT);
- for (SmallVector<unsigned, 4>::iterator I = ColdEdges.begin(),
- E = ColdEdges.end();
+ for (SmallVectorImpl<unsigned>::iterator I = ColdEdges.begin(),
+ E = ColdEdges.end();
I != E; ++I)
setEdgeWeight(BB, *I, ColdWeight);
return true;
uint32_t NormalWeight = std::max(
CC_NONTAKEN_WEIGHT / (unsigned) NormalEdges.size(), NORMAL_WEIGHT);
- for (SmallVector<unsigned, 4>::iterator I = NormalEdges.begin(),
- E = NormalEdges.end();
+ for (SmallVectorImpl<unsigned>::iterator I = NormalEdges.begin(),
+ E = NormalEdges.end();
I != E; ++I)
setEdgeWeight(BB, *I, NormalWeight);
InEdges.push_back(I.getSuccessorIndex());
}
+ if (BackEdges.empty() && ExitingEdges.empty())
+ return false;
+
if (uint32_t numBackEdges = BackEdges.size()) {
uint32_t backWeight = LBH_TAKEN_WEIGHT / numBackEdges;
if (backWeight < NORMAL_WEIGHT)
backWeight = NORMAL_WEIGHT;
- for (SmallVector<unsigned, 8>::iterator EI = BackEdges.begin(),
+ for (SmallVectorImpl<unsigned>::iterator EI = BackEdges.begin(),
EE = BackEdges.end(); EI != EE; ++EI) {
setEdgeWeight(BB, *EI, backWeight);
}
if (inWeight < NORMAL_WEIGHT)
inWeight = NORMAL_WEIGHT;
- for (SmallVector<unsigned, 8>::iterator EI = InEdges.begin(),
+ for (SmallVectorImpl<unsigned>::iterator EI = InEdges.begin(),
EE = InEdges.end(); EI != EE; ++EI) {
setEdgeWeight(BB, *EI, inWeight);
}
if (exitWeight < MIN_WEIGHT)
exitWeight = MIN_WEIGHT;
- for (SmallVector<unsigned, 8>::iterator EI = ExitingEdges.begin(),
+ for (SmallVectorImpl<unsigned>::iterator EI = ExitingEdges.begin(),
EE = ExitingEdges.end(); EI != EE; ++EI) {
setEdgeWeight(BB, *EI, exitWeight);
}
// InstCombine canonicalizes X <= 0 into X < 1.
// X <= 0 -> Unlikely
isProb = false;
- } else if (CV->isAllOnesValue() && CI->getPredicate() == CmpInst::ICMP_SGT) {
- // InstCombine canonicalizes X >= 0 into X > -1.
- // X >= 0 -> Likely
- isProb = true;
+ } else if (CV->isAllOnesValue()) {
+ switch (CI->getPredicate()) {
+ case CmpInst::ICMP_EQ:
+ // X == -1 -> Unlikely
+ isProb = false;
+ break;
+ case CmpInst::ICMP_NE:
+ // X != -1 -> Likely
+ isProb = true;
+ break;
+ case CmpInst::ICMP_SGT:
+ // InstCombine canonicalizes X >= 0 into X > -1.
+ // X >= 0 -> Likely
+ isProb = true;
+ break;
+ default:
+ return false;
+ }
} else {
return false;
}
}
void BranchProbabilityInfo::getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequired<LoopInfo>();
+ AU.addRequired<LoopInfoWrapperPass>();
AU.setPreservesAll();
}
bool BranchProbabilityInfo::runOnFunction(Function &F) {
+ DEBUG(dbgs() << "---- Branch Probability Info : " << F.getName()
+ << " ----\n\n");
LastF = &F; // Store the last function we ran on for printing.
- LI = &getAnalysis<LoopInfo>();
+ LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
assert(PostDominatedByUnreachable.empty());
assert(PostDominatedByColdCall.empty());
BasicBlock *BranchProbabilityInfo::getHotSucc(BasicBlock *BB) const {
uint32_t Sum = 0;
uint32_t MaxWeight = 0;
- BasicBlock *MaxSucc = 0;
+ BasicBlock *MaxSucc = nullptr;
for (succ_iterator I = succ_begin(BB), E = succ_end(BB); I != E; ++I) {
BasicBlock *Succ = *I;
if (BranchProbability(MaxWeight, Sum) > BranchProbability(4, 5))
return MaxSucc;
- return 0;
+ return nullptr;
}
/// Get the raw edge weight for the edge. If can't find it, return
return DEFAULT_WEIGHT;
}
+uint32_t BranchProbabilityInfo::getEdgeWeight(const BasicBlock *Src,
+ succ_const_iterator Dst) const {
+ return getEdgeWeight(Src, Dst.getSuccessorIndex());
+}
+
/// Get the raw edge weight calculated for the block pair. This returns the sum
/// of all raw edge weights from Src to Dst.
uint32_t BranchProbabilityInfo::