1 //===-- BranchProbabilityInfo.cpp - Branch Probability Analysis -----------===//
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 // Loops should be simplified before this analysis.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Analysis/BranchProbabilityInfo.h"
15 #include "llvm/ADT/PostOrderIterator.h"
16 #include "llvm/Analysis/LoopInfo.h"
17 #include "llvm/IR/CFG.h"
18 #include "llvm/IR/Constants.h"
19 #include "llvm/IR/Function.h"
20 #include "llvm/IR/Instructions.h"
21 #include "llvm/IR/LLVMContext.h"
22 #include "llvm/IR/Metadata.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/Support/raw_ostream.h"
28 #define DEBUG_TYPE "branch-prob"
30 INITIALIZE_PASS_BEGIN(BranchProbabilityInfoWrapperPass, "branch-prob",
31 "Branch Probability Analysis", false, true)
32 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
33 INITIALIZE_PASS_END(BranchProbabilityInfoWrapperPass, "branch-prob",
34 "Branch Probability Analysis", false, true)
36 char BranchProbabilityInfoWrapperPass::ID = 0;
38 // Weights are for internal use only. They are used by heuristics to help to
39 // estimate edges' probability. Example:
41 // Using "Loop Branch Heuristics" we predict weights of edges for the
56 // Probability of the edge BB2->BB1 = 124 / (124 + 4) = 0.96875
57 // Probability of the edge BB2->BB3 = 4 / (124 + 4) = 0.03125
58 static const uint32_t LBH_TAKEN_WEIGHT = 124;
59 static const uint32_t LBH_NONTAKEN_WEIGHT = 4;
61 /// \brief Unreachable-terminating branch taken weight.
63 /// This is the weight for a branch being taken to a block that terminates
64 /// (eventually) in unreachable. These are predicted as unlikely as possible.
65 static const uint32_t UR_TAKEN_WEIGHT = 1;
67 /// \brief Unreachable-terminating branch not-taken weight.
69 /// This is the weight for a branch not being taken toward a block that
70 /// terminates (eventually) in unreachable. Such a branch is essentially never
71 /// taken. Set the weight to an absurdly high value so that nested loops don't
72 /// easily subsume it.
73 static const uint32_t UR_NONTAKEN_WEIGHT = 1024*1024 - 1;
75 /// \brief Weight for a branch taken going into a cold block.
77 /// This is the weight for a branch taken toward a block marked
78 /// cold. A block is marked cold if it's postdominated by a
79 /// block containing a call to a cold function. Cold functions
80 /// are those marked with attribute 'cold'.
81 static const uint32_t CC_TAKEN_WEIGHT = 4;
83 /// \brief Weight for a branch not-taken into a cold block.
85 /// This is the weight for a branch not taken toward a block marked
87 static const uint32_t CC_NONTAKEN_WEIGHT = 64;
89 static const uint32_t PH_TAKEN_WEIGHT = 20;
90 static const uint32_t PH_NONTAKEN_WEIGHT = 12;
92 static const uint32_t ZH_TAKEN_WEIGHT = 20;
93 static const uint32_t ZH_NONTAKEN_WEIGHT = 12;
95 static const uint32_t FPH_TAKEN_WEIGHT = 20;
96 static const uint32_t FPH_NONTAKEN_WEIGHT = 12;
98 /// \brief Invoke-terminating normal branch taken weight
100 /// This is the weight for branching to the normal destination of an invoke
101 /// instruction. We expect this to happen most of the time. Set the weight to an
102 /// absurdly high value so that nested loops subsume it.
103 static const uint32_t IH_TAKEN_WEIGHT = 1024 * 1024 - 1;
105 /// \brief Invoke-terminating normal branch not-taken weight.
107 /// This is the weight for branching to the unwind destination of an invoke
108 /// instruction. This is essentially never taken.
109 static const uint32_t IH_NONTAKEN_WEIGHT = 1;
111 /// \brief Calculate edge weights for successors lead to unreachable.
113 /// Predict that a successor which leads necessarily to an
114 /// unreachable-terminated block as extremely unlikely.
115 bool BranchProbabilityInfo::calcUnreachableHeuristics(const BasicBlock *BB) {
116 const TerminatorInst *TI = BB->getTerminator();
117 if (TI->getNumSuccessors() == 0) {
118 if (isa<UnreachableInst>(TI) ||
119 // If this block is terminated by a call to
120 // @llvm.experimental.deoptimize then treat it like an unreachable since
121 // the @llvm.experimental.deoptimize call is expected to practically
123 BB->getTerminatingDeoptimizeCall())
124 PostDominatedByUnreachable.insert(BB);
128 SmallVector<unsigned, 4> UnreachableEdges;
129 SmallVector<unsigned, 4> ReachableEdges;
131 for (succ_const_iterator I = succ_begin(BB), E = succ_end(BB); I != E; ++I) {
132 if (PostDominatedByUnreachable.count(*I))
133 UnreachableEdges.push_back(I.getSuccessorIndex());
135 ReachableEdges.push_back(I.getSuccessorIndex());
138 // If all successors are in the set of blocks post-dominated by unreachable,
139 // this block is too.
140 if (UnreachableEdges.size() == TI->getNumSuccessors())
141 PostDominatedByUnreachable.insert(BB);
143 // Skip probabilities if this block has a single successor or if all were
145 if (TI->getNumSuccessors() == 1 || UnreachableEdges.empty())
148 // If the terminator is an InvokeInst, check only the normal destination block
149 // as the unwind edge of InvokeInst is also very unlikely taken.
150 if (auto *II = dyn_cast<InvokeInst>(TI))
151 if (PostDominatedByUnreachable.count(II->getNormalDest())) {
152 PostDominatedByUnreachable.insert(BB);
153 // Return false here so that edge weights for InvokeInst could be decided
154 // in calcInvokeHeuristics().
158 if (ReachableEdges.empty()) {
159 BranchProbability Prob(1, UnreachableEdges.size());
160 for (unsigned SuccIdx : UnreachableEdges)
161 setEdgeProbability(BB, SuccIdx, Prob);
165 auto UnreachableProb = BranchProbability::getBranchProbability(
166 UR_TAKEN_WEIGHT, (UR_TAKEN_WEIGHT + UR_NONTAKEN_WEIGHT) *
167 uint64_t(UnreachableEdges.size()));
168 auto ReachableProb = BranchProbability::getBranchProbability(
170 (UR_TAKEN_WEIGHT + UR_NONTAKEN_WEIGHT) * uint64_t(ReachableEdges.size()));
172 for (unsigned SuccIdx : UnreachableEdges)
173 setEdgeProbability(BB, SuccIdx, UnreachableProb);
174 for (unsigned SuccIdx : ReachableEdges)
175 setEdgeProbability(BB, SuccIdx, ReachableProb);
180 // Propagate existing explicit probabilities from either profile data or
181 // 'expect' intrinsic processing.
182 bool BranchProbabilityInfo::calcMetadataWeights(const BasicBlock *BB) {
183 const TerminatorInst *TI = BB->getTerminator();
184 if (TI->getNumSuccessors() == 1)
186 if (!isa<BranchInst>(TI) && !isa<SwitchInst>(TI))
189 MDNode *WeightsNode = TI->getMetadata(LLVMContext::MD_prof);
193 // Check that the number of successors is manageable.
194 assert(TI->getNumSuccessors() < UINT32_MAX && "Too many successors");
196 // Ensure there are weights for all of the successors. Note that the first
197 // operand to the metadata node is a name, not a weight.
198 if (WeightsNode->getNumOperands() != TI->getNumSuccessors() + 1)
201 // Build up the final weights that will be used in a temporary buffer.
202 // Compute the sum of all weights to later decide whether they need to
203 // be scaled to fit in 32 bits.
204 uint64_t WeightSum = 0;
205 SmallVector<uint32_t, 2> Weights;
206 Weights.reserve(TI->getNumSuccessors());
207 for (unsigned i = 1, e = WeightsNode->getNumOperands(); i != e; ++i) {
208 ConstantInt *Weight =
209 mdconst::dyn_extract<ConstantInt>(WeightsNode->getOperand(i));
212 assert(Weight->getValue().getActiveBits() <= 32 &&
213 "Too many bits for uint32_t");
214 Weights.push_back(Weight->getZExtValue());
215 WeightSum += Weights.back();
217 assert(Weights.size() == TI->getNumSuccessors() && "Checked above");
219 // If the sum of weights does not fit in 32 bits, scale every weight down
221 uint64_t ScalingFactor =
222 (WeightSum > UINT32_MAX) ? WeightSum / UINT32_MAX + 1 : 1;
225 for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
226 Weights[i] /= ScalingFactor;
227 WeightSum += Weights[i];
230 if (WeightSum == 0) {
231 for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
232 setEdgeProbability(BB, i, {1, e});
234 for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
235 setEdgeProbability(BB, i, {Weights[i], static_cast<uint32_t>(WeightSum)});
238 assert(WeightSum <= UINT32_MAX &&
239 "Expected weights to scale down to 32 bits");
244 /// \brief Calculate edge weights for edges leading to cold blocks.
246 /// A cold block is one post-dominated by a block with a call to a
247 /// cold function. Those edges are unlikely to be taken, so we give
248 /// them relatively low weight.
250 /// Return true if we could compute the weights for cold edges.
251 /// Return false, otherwise.
252 bool BranchProbabilityInfo::calcColdCallHeuristics(const BasicBlock *BB) {
253 const TerminatorInst *TI = BB->getTerminator();
254 if (TI->getNumSuccessors() == 0)
257 // Determine which successors are post-dominated by a cold block.
258 SmallVector<unsigned, 4> ColdEdges;
259 SmallVector<unsigned, 4> NormalEdges;
260 for (succ_const_iterator I = succ_begin(BB), E = succ_end(BB); I != E; ++I)
261 if (PostDominatedByColdCall.count(*I))
262 ColdEdges.push_back(I.getSuccessorIndex());
264 NormalEdges.push_back(I.getSuccessorIndex());
266 // If all successors are in the set of blocks post-dominated by cold calls,
267 // this block is in the set post-dominated by cold calls.
268 if (ColdEdges.size() == TI->getNumSuccessors())
269 PostDominatedByColdCall.insert(BB);
271 // Otherwise, if the block itself contains a cold function, add it to the
272 // set of blocks postdominated by a cold call.
273 assert(!PostDominatedByColdCall.count(BB));
274 for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I)
275 if (const CallInst *CI = dyn_cast<CallInst>(I))
276 if (CI->hasFnAttr(Attribute::Cold)) {
277 PostDominatedByColdCall.insert(BB);
282 if (auto *II = dyn_cast<InvokeInst>(TI)) {
283 // If the terminator is an InvokeInst, consider only the normal destination
285 if (PostDominatedByColdCall.count(II->getNormalDest()))
286 PostDominatedByColdCall.insert(BB);
287 // Return false here so that edge weights for InvokeInst could be decided
288 // in calcInvokeHeuristics().
292 // Skip probabilities if this block has a single successor.
293 if (TI->getNumSuccessors() == 1 || ColdEdges.empty())
296 if (NormalEdges.empty()) {
297 BranchProbability Prob(1, ColdEdges.size());
298 for (unsigned SuccIdx : ColdEdges)
299 setEdgeProbability(BB, SuccIdx, Prob);
303 auto ColdProb = BranchProbability::getBranchProbability(
305 (CC_TAKEN_WEIGHT + CC_NONTAKEN_WEIGHT) * uint64_t(ColdEdges.size()));
306 auto NormalProb = BranchProbability::getBranchProbability(
308 (CC_TAKEN_WEIGHT + CC_NONTAKEN_WEIGHT) * uint64_t(NormalEdges.size()));
310 for (unsigned SuccIdx : ColdEdges)
311 setEdgeProbability(BB, SuccIdx, ColdProb);
312 for (unsigned SuccIdx : NormalEdges)
313 setEdgeProbability(BB, SuccIdx, NormalProb);
318 // Calculate Edge Weights using "Pointer Heuristics". Predict a comparsion
319 // between two pointer or pointer and NULL will fail.
320 bool BranchProbabilityInfo::calcPointerHeuristics(const BasicBlock *BB) {
321 const BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
322 if (!BI || !BI->isConditional())
325 Value *Cond = BI->getCondition();
326 ICmpInst *CI = dyn_cast<ICmpInst>(Cond);
327 if (!CI || !CI->isEquality())
330 Value *LHS = CI->getOperand(0);
332 if (!LHS->getType()->isPointerTy())
335 assert(CI->getOperand(1)->getType()->isPointerTy());
337 // p != 0 -> isProb = true
338 // p == 0 -> isProb = false
339 // p != q -> isProb = true
340 // p == q -> isProb = false;
341 unsigned TakenIdx = 0, NonTakenIdx = 1;
342 bool isProb = CI->getPredicate() == ICmpInst::ICMP_NE;
344 std::swap(TakenIdx, NonTakenIdx);
346 BranchProbability TakenProb(PH_TAKEN_WEIGHT,
347 PH_TAKEN_WEIGHT + PH_NONTAKEN_WEIGHT);
348 setEdgeProbability(BB, TakenIdx, TakenProb);
349 setEdgeProbability(BB, NonTakenIdx, TakenProb.getCompl());
353 // Calculate Edge Weights using "Loop Branch Heuristics". Predict backedges
354 // as taken, exiting edges as not-taken.
355 bool BranchProbabilityInfo::calcLoopBranchHeuristics(const BasicBlock *BB,
356 const LoopInfo &LI) {
357 Loop *L = LI.getLoopFor(BB);
361 SmallVector<unsigned, 8> BackEdges;
362 SmallVector<unsigned, 8> ExitingEdges;
363 SmallVector<unsigned, 8> InEdges; // Edges from header to the loop.
365 for (succ_const_iterator I = succ_begin(BB), E = succ_end(BB); I != E; ++I) {
366 if (!L->contains(*I))
367 ExitingEdges.push_back(I.getSuccessorIndex());
368 else if (L->getHeader() == *I)
369 BackEdges.push_back(I.getSuccessorIndex());
371 InEdges.push_back(I.getSuccessorIndex());
374 if (BackEdges.empty() && ExitingEdges.empty())
377 // Collect the sum of probabilities of back-edges/in-edges/exiting-edges, and
378 // normalize them so that they sum up to one.
379 BranchProbability Probs[] = {BranchProbability::getZero(),
380 BranchProbability::getZero(),
381 BranchProbability::getZero()};
382 unsigned Denom = (BackEdges.empty() ? 0 : LBH_TAKEN_WEIGHT) +
383 (InEdges.empty() ? 0 : LBH_TAKEN_WEIGHT) +
384 (ExitingEdges.empty() ? 0 : LBH_NONTAKEN_WEIGHT);
385 if (!BackEdges.empty())
386 Probs[0] = BranchProbability(LBH_TAKEN_WEIGHT, Denom);
387 if (!InEdges.empty())
388 Probs[1] = BranchProbability(LBH_TAKEN_WEIGHT, Denom);
389 if (!ExitingEdges.empty())
390 Probs[2] = BranchProbability(LBH_NONTAKEN_WEIGHT, Denom);
392 if (uint32_t numBackEdges = BackEdges.size()) {
393 auto Prob = Probs[0] / numBackEdges;
394 for (unsigned SuccIdx : BackEdges)
395 setEdgeProbability(BB, SuccIdx, Prob);
398 if (uint32_t numInEdges = InEdges.size()) {
399 auto Prob = Probs[1] / numInEdges;
400 for (unsigned SuccIdx : InEdges)
401 setEdgeProbability(BB, SuccIdx, Prob);
404 if (uint32_t numExitingEdges = ExitingEdges.size()) {
405 auto Prob = Probs[2] / numExitingEdges;
406 for (unsigned SuccIdx : ExitingEdges)
407 setEdgeProbability(BB, SuccIdx, Prob);
413 bool BranchProbabilityInfo::calcZeroHeuristics(const BasicBlock *BB) {
414 const BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
415 if (!BI || !BI->isConditional())
418 Value *Cond = BI->getCondition();
419 ICmpInst *CI = dyn_cast<ICmpInst>(Cond);
423 Value *RHS = CI->getOperand(1);
424 ConstantInt *CV = dyn_cast<ConstantInt>(RHS);
428 // If the LHS is the result of AND'ing a value with a single bit bitmask,
429 // we don't have information about probabilities.
430 if (Instruction *LHS = dyn_cast<Instruction>(CI->getOperand(0)))
431 if (LHS->getOpcode() == Instruction::And)
432 if (ConstantInt *AndRHS = dyn_cast<ConstantInt>(LHS->getOperand(1)))
433 if (AndRHS->getUniqueInteger().isPowerOf2())
438 switch (CI->getPredicate()) {
439 case CmpInst::ICMP_EQ:
440 // X == 0 -> Unlikely
443 case CmpInst::ICMP_NE:
447 case CmpInst::ICMP_SLT:
451 case CmpInst::ICMP_SGT:
458 } else if (CV->isOne() && CI->getPredicate() == CmpInst::ICMP_SLT) {
459 // InstCombine canonicalizes X <= 0 into X < 1.
460 // X <= 0 -> Unlikely
462 } else if (CV->isAllOnesValue()) {
463 switch (CI->getPredicate()) {
464 case CmpInst::ICMP_EQ:
465 // X == -1 -> Unlikely
468 case CmpInst::ICMP_NE:
472 case CmpInst::ICMP_SGT:
473 // InstCombine canonicalizes X >= 0 into X > -1.
484 unsigned TakenIdx = 0, NonTakenIdx = 1;
487 std::swap(TakenIdx, NonTakenIdx);
489 BranchProbability TakenProb(ZH_TAKEN_WEIGHT,
490 ZH_TAKEN_WEIGHT + ZH_NONTAKEN_WEIGHT);
491 setEdgeProbability(BB, TakenIdx, TakenProb);
492 setEdgeProbability(BB, NonTakenIdx, TakenProb.getCompl());
496 bool BranchProbabilityInfo::calcFloatingPointHeuristics(const BasicBlock *BB) {
497 const BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
498 if (!BI || !BI->isConditional())
501 Value *Cond = BI->getCondition();
502 FCmpInst *FCmp = dyn_cast<FCmpInst>(Cond);
507 if (FCmp->isEquality()) {
508 // f1 == f2 -> Unlikely
509 // f1 != f2 -> Likely
510 isProb = !FCmp->isTrueWhenEqual();
511 } else if (FCmp->getPredicate() == FCmpInst::FCMP_ORD) {
514 } else if (FCmp->getPredicate() == FCmpInst::FCMP_UNO) {
521 unsigned TakenIdx = 0, NonTakenIdx = 1;
524 std::swap(TakenIdx, NonTakenIdx);
526 BranchProbability TakenProb(FPH_TAKEN_WEIGHT,
527 FPH_TAKEN_WEIGHT + FPH_NONTAKEN_WEIGHT);
528 setEdgeProbability(BB, TakenIdx, TakenProb);
529 setEdgeProbability(BB, NonTakenIdx, TakenProb.getCompl());
533 bool BranchProbabilityInfo::calcInvokeHeuristics(const BasicBlock *BB) {
534 const InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator());
538 BranchProbability TakenProb(IH_TAKEN_WEIGHT,
539 IH_TAKEN_WEIGHT + IH_NONTAKEN_WEIGHT);
540 setEdgeProbability(BB, 0 /*Index for Normal*/, TakenProb);
541 setEdgeProbability(BB, 1 /*Index for Unwind*/, TakenProb.getCompl());
545 void BranchProbabilityInfo::releaseMemory() {
549 void BranchProbabilityInfo::print(raw_ostream &OS) const {
550 OS << "---- Branch Probabilities ----\n";
551 // We print the probabilities from the last function the analysis ran over,
552 // or the function it is currently running over.
553 assert(LastF && "Cannot print prior to running over a function");
554 for (const auto &BI : *LastF) {
555 for (succ_const_iterator SI = succ_begin(&BI), SE = succ_end(&BI); SI != SE;
557 printEdgeProbability(OS << " ", &BI, *SI);
562 bool BranchProbabilityInfo::
563 isEdgeHot(const BasicBlock *Src, const BasicBlock *Dst) const {
564 // Hot probability is at least 4/5 = 80%
565 // FIXME: Compare against a static "hot" BranchProbability.
566 return getEdgeProbability(Src, Dst) > BranchProbability(4, 5);
570 BranchProbabilityInfo::getHotSucc(const BasicBlock *BB) const {
571 auto MaxProb = BranchProbability::getZero();
572 const BasicBlock *MaxSucc = nullptr;
574 for (succ_const_iterator I = succ_begin(BB), E = succ_end(BB); I != E; ++I) {
575 const BasicBlock *Succ = *I;
576 auto Prob = getEdgeProbability(BB, Succ);
577 if (Prob > MaxProb) {
583 // Hot probability is at least 4/5 = 80%
584 if (MaxProb > BranchProbability(4, 5))
590 /// Get the raw edge probability for the edge. If can't find it, return a
591 /// default probability 1/N where N is the number of successors. Here an edge is
592 /// specified using PredBlock and an
593 /// index to the successors.
595 BranchProbabilityInfo::getEdgeProbability(const BasicBlock *Src,
596 unsigned IndexInSuccessors) const {
597 auto I = Probs.find(std::make_pair(Src, IndexInSuccessors));
599 if (I != Probs.end())
603 static_cast<uint32_t>(std::distance(succ_begin(Src), succ_end(Src)))};
607 BranchProbabilityInfo::getEdgeProbability(const BasicBlock *Src,
608 succ_const_iterator Dst) const {
609 return getEdgeProbability(Src, Dst.getSuccessorIndex());
612 /// Get the raw edge probability calculated for the block pair. This returns the
613 /// sum of all raw edge probabilities from Src to Dst.
615 BranchProbabilityInfo::getEdgeProbability(const BasicBlock *Src,
616 const BasicBlock *Dst) const {
617 auto Prob = BranchProbability::getZero();
618 bool FoundProb = false;
619 for (succ_const_iterator I = succ_begin(Src), E = succ_end(Src); I != E; ++I)
621 auto MapI = Probs.find(std::make_pair(Src, I.getSuccessorIndex()));
622 if (MapI != Probs.end()) {
624 Prob += MapI->second;
627 uint32_t succ_num = std::distance(succ_begin(Src), succ_end(Src));
628 return FoundProb ? Prob : BranchProbability(1, succ_num);
631 /// Set the edge probability for a given edge specified by PredBlock and an
632 /// index to the successors.
633 void BranchProbabilityInfo::setEdgeProbability(const BasicBlock *Src,
634 unsigned IndexInSuccessors,
635 BranchProbability Prob) {
636 Probs[std::make_pair(Src, IndexInSuccessors)] = Prob;
637 Handles.insert(BasicBlockCallbackVH(Src, this));
638 DEBUG(dbgs() << "set edge " << Src->getName() << " -> " << IndexInSuccessors
639 << " successor probability to " << Prob << "\n");
643 BranchProbabilityInfo::printEdgeProbability(raw_ostream &OS,
644 const BasicBlock *Src,
645 const BasicBlock *Dst) const {
647 const BranchProbability Prob = getEdgeProbability(Src, Dst);
648 OS << "edge " << Src->getName() << " -> " << Dst->getName()
649 << " probability is " << Prob
650 << (isEdgeHot(Src, Dst) ? " [HOT edge]\n" : "\n");
655 void BranchProbabilityInfo::eraseBlock(const BasicBlock *BB) {
656 for (auto I = Probs.begin(), E = Probs.end(); I != E; ++I) {
663 void BranchProbabilityInfo::calculate(const Function &F, const LoopInfo &LI) {
664 DEBUG(dbgs() << "---- Branch Probability Info : " << F.getName()
666 LastF = &F; // Store the last function we ran on for printing.
667 assert(PostDominatedByUnreachable.empty());
668 assert(PostDominatedByColdCall.empty());
670 // Walk the basic blocks in post-order so that we can build up state about
671 // the successors of a block iteratively.
672 for (auto BB : post_order(&F.getEntryBlock())) {
673 DEBUG(dbgs() << "Computing probabilities for " << BB->getName() << "\n");
674 if (calcUnreachableHeuristics(BB))
676 if (calcMetadataWeights(BB))
678 if (calcColdCallHeuristics(BB))
680 if (calcLoopBranchHeuristics(BB, LI))
682 if (calcPointerHeuristics(BB))
684 if (calcZeroHeuristics(BB))
686 if (calcFloatingPointHeuristics(BB))
688 calcInvokeHeuristics(BB);
691 PostDominatedByUnreachable.clear();
692 PostDominatedByColdCall.clear();
695 void BranchProbabilityInfoWrapperPass::getAnalysisUsage(
696 AnalysisUsage &AU) const {
697 AU.addRequired<LoopInfoWrapperPass>();
698 AU.setPreservesAll();
701 bool BranchProbabilityInfoWrapperPass::runOnFunction(Function &F) {
702 const LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
703 BPI.calculate(F, LI);
707 void BranchProbabilityInfoWrapperPass::releaseMemory() { BPI.releaseMemory(); }
709 void BranchProbabilityInfoWrapperPass::print(raw_ostream &OS,
710 const Module *) const {
714 AnalysisKey BranchProbabilityAnalysis::Key;
715 BranchProbabilityInfo
716 BranchProbabilityAnalysis::run(Function &F, FunctionAnalysisManager &AM) {
717 BranchProbabilityInfo BPI;
718 BPI.calculate(F, AM.getResult<LoopAnalysis>(F));
723 BranchProbabilityPrinterPass::run(Function &F, FunctionAnalysisManager &AM) {
724 OS << "Printing analysis results of BPI for function "
725 << "'" << F.getName() << "':"
727 AM.getResult<BranchProbabilityAnalysis>(F).print(OS);
728 return PreservedAnalyses::all();