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[BPI] NFC: reorder ifs to bail out earlier 

This is non-functional change to re-order if statements to bail out earlier
from unreachable and ColdCall heuristics.

Reviewers: sanjoy, reames, junbuml, vsk, chandlerc

Reviewed By: chandlerc

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D31704

llvm-svn: 300442
This commit is contained in:
Serguei Katkov 2017-04-17 06:39:47 +00:00
parent 8ed6b66d85
commit 11d9c4f691
1 changed files with 18 additions and 19 deletions
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37
llvm/lib/Analysis/BranchProbabilityInfo.cpp
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@ -205,7 +205,11 @@ BranchProbabilityInfo::updatePostDominatedByColdCall(const BasicBlock *BB) {
/// unreachable-terminated block as extremely unlikely.
bool BranchProbabilityInfo::calcUnreachableHeuristics(const BasicBlock *BB) {
const TerminatorInst *TI = BB->getTerminator();
if (TI->getNumSuccessors() == 0)
assert(TI->getNumSuccessors() > 1 && "expected more than one successor!");
// Return false here so that edge weights for InvokeInst could be decided
// in calcInvokeHeuristics().
if (isa<InvokeInst>(TI))
return false;
SmallVector<unsigned, 4> UnreachableEdges;
@ -217,14 +221,8 @@ bool BranchProbabilityInfo::calcUnreachableHeuristics(const BasicBlock *BB) {
else
ReachableEdges.push_back(I.getSuccessorIndex());
// Skip probabilities if this block has a single successor or if all were
// reachable.
if (TI->getNumSuccessors() == 1 || UnreachableEdges.empty())
return false;
// Return false here so that edge weights for InvokeInst could be decided
// in calcInvokeHeuristics().
if (isa<InvokeInst>(TI))
// Skip probabilities if all were reachable.
if (UnreachableEdges.empty())
return false;
if (ReachableEdges.empty()) {
@ -251,8 +249,7 @@ bool BranchProbabilityInfo::calcUnreachableHeuristics(const BasicBlock *BB) {
// set to min of metadata and unreachable heuristic.
bool BranchProbabilityInfo::calcMetadataWeights(const BasicBlock *BB) {
const TerminatorInst *TI = BB->getTerminator();
if (TI->getNumSuccessors() <= 1)
return false;
assert(TI->getNumSuccessors() > 1 && "expected more than one successor!");
if (!isa<BranchInst>(TI) && !isa<SwitchInst>(TI))
return false;
@ -359,7 +356,11 @@ bool BranchProbabilityInfo::calcMetadataWeights(const BasicBlock *BB) {
/// Return false, otherwise.
bool BranchProbabilityInfo::calcColdCallHeuristics(const BasicBlock *BB) {
const TerminatorInst *TI = BB->getTerminator();
if (TI->getNumSuccessors() == 0)
assert(TI->getNumSuccessors() > 1 && "expected more than one successor!");
// Return false here so that edge weights for InvokeInst could be decided
// in calcInvokeHeuristics().
if (isa<InvokeInst>(TI))
return false;
// Determine which successors are post-dominated by a cold block.
@ -371,13 +372,8 @@ bool BranchProbabilityInfo::calcColdCallHeuristics(const BasicBlock *BB) {
else
NormalEdges.push_back(I.getSuccessorIndex());
// Return false here so that edge weights for InvokeInst could be decided
// in calcInvokeHeuristics().
if (isa<InvokeInst>(TI))
return false;
// Skip probabilities if this block has a single successor.
if (TI->getNumSuccessors() == 1 || ColdEdges.empty())
// Skip probabilities if no cold edges.
if (ColdEdges.empty())
return false;
if (NormalEdges.empty()) {
@ -760,6 +756,9 @@ void BranchProbabilityInfo::calculate(const Function &F, const LoopInfo &LI) {
DEBUG(dbgs() << "Computing probabilities for " << BB->getName() << "\n");
updatePostDominatedByUnreachable(BB);
updatePostDominatedByColdCall(BB);
// If there is no at least two successors, no sense to set probability.
if (BB->getTerminator()->getNumSuccessors() < 2)
continue;
if (calcMetadataWeights(BB))
continue;
if (calcUnreachableHeuristics(BB))