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Diffstat (limited to 'lib/Transforms/Scalar/LoopUnswitch.cpp')
-rw-r--r--lib/Transforms/Scalar/LoopUnswitch.cpp97
1 files changed, 51 insertions, 46 deletions
diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp
index bd468338a1d0..b12586758925 100644
--- a/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -28,7 +28,7 @@
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AssumptionCache.h"
@@ -39,6 +39,7 @@
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/Transforms/Utils/Local.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CallSite.h"
@@ -66,7 +67,6 @@
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
-#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/LoopUtils.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
#include <algorithm>
@@ -298,9 +298,9 @@ bool LUAnalysisCache::countLoop(const Loop *L, const TargetTransformInfo &TTI,
MaxSize -= Props.SizeEstimation * Props.CanBeUnswitchedCount;
if (Metrics.notDuplicatable) {
- DEBUG(dbgs() << "NOT unswitching loop %"
- << L->getHeader()->getName() << ", contents cannot be "
- << "duplicated!\n");
+ LLVM_DEBUG(dbgs() << "NOT unswitching loop %" << L->getHeader()->getName()
+ << ", contents cannot be "
+ << "duplicated!\n");
return false;
}
}
@@ -635,6 +635,12 @@ bool LoopUnswitch::processCurrentLoop() {
return true;
}
+ // Do not do non-trivial unswitch while optimizing for size.
+ // FIXME: Use Function::optForSize().
+ if (OptimizeForSize ||
+ loopHeader->getParent()->hasFnAttribute(Attribute::OptimizeForSize))
+ return false;
+
// Run through the instructions in the loop, keeping track of three things:
//
// - That we do not unswitch loops containing convergent operations, as we
@@ -666,12 +672,6 @@ bool LoopUnswitch::processCurrentLoop() {
}
}
- // Do not do non-trivial unswitch while optimizing for size.
- // FIXME: Use Function::optForSize().
- if (OptimizeForSize ||
- loopHeader->getParent()->hasFnAttribute(Attribute::OptimizeForSize))
- return false;
-
for (IntrinsicInst *Guard : Guards) {
Value *LoopCond =
FindLIVLoopCondition(Guard->getOperand(0), currentLoop, Changed).first;
@@ -856,20 +856,20 @@ bool LoopUnswitch::UnswitchIfProfitable(Value *LoopCond, Constant *Val,
TerminatorInst *TI) {
// Check to see if it would be profitable to unswitch current loop.
if (!BranchesInfo.CostAllowsUnswitching()) {
- DEBUG(dbgs() << "NOT unswitching loop %"
- << currentLoop->getHeader()->getName()
- << " at non-trivial condition '" << *Val
- << "' == " << *LoopCond << "\n"
- << ". Cost too high.\n");
+ LLVM_DEBUG(dbgs() << "NOT unswitching loop %"
+ << currentLoop->getHeader()->getName()
+ << " at non-trivial condition '" << *Val
+ << "' == " << *LoopCond << "\n"
+ << ". Cost too high.\n");
return false;
}
if (hasBranchDivergence &&
getAnalysis<DivergenceAnalysis>().isDivergent(LoopCond)) {
- DEBUG(dbgs() << "NOT unswitching loop %"
- << currentLoop->getHeader()->getName()
- << " at non-trivial condition '" << *Val
- << "' == " << *LoopCond << "\n"
- << ". Condition is divergent.\n");
+ LLVM_DEBUG(dbgs() << "NOT unswitching loop %"
+ << currentLoop->getHeader()->getName()
+ << " at non-trivial condition '" << *Val
+ << "' == " << *LoopCond << "\n"
+ << ". Condition is divergent.\n");
return false;
}
@@ -910,6 +910,7 @@ void LoopUnswitch::EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val,
BranchInst *OldBranch,
TerminatorInst *TI) {
assert(OldBranch->isUnconditional() && "Preheader is not split correctly");
+ assert(TrueDest != FalseDest && "Branch targets should be different");
// Insert a conditional branch on LIC to the two preheaders. The original
// code is the true version and the new code is the false version.
Value *BranchVal = LIC;
@@ -942,9 +943,9 @@ void LoopUnswitch::EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val,
if (DT) {
// First, add both successors.
SmallVector<DominatorTree::UpdateType, 3> Updates;
- if (TrueDest != OldBranchParent)
+ if (TrueDest != OldBranchSucc)
Updates.push_back({DominatorTree::Insert, OldBranchParent, TrueDest});
- if (FalseDest != OldBranchParent)
+ if (FalseDest != OldBranchSucc)
Updates.push_back({DominatorTree::Insert, OldBranchParent, FalseDest});
// If both of the new successors are different from the old one, inform the
// DT that the edge was deleted.
@@ -970,11 +971,15 @@ void LoopUnswitch::EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val,
void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond, Constant *Val,
BasicBlock *ExitBlock,
TerminatorInst *TI) {
- DEBUG(dbgs() << "loop-unswitch: Trivial-Unswitch loop %"
- << loopHeader->getName() << " [" << L->getBlocks().size()
- << " blocks] in Function "
- << L->getHeader()->getParent()->getName() << " on cond: " << *Val
- << " == " << *Cond << "\n");
+ LLVM_DEBUG(dbgs() << "loop-unswitch: Trivial-Unswitch loop %"
+ << loopHeader->getName() << " [" << L->getBlocks().size()
+ << " blocks] in Function "
+ << L->getHeader()->getParent()->getName()
+ << " on cond: " << *Val << " == " << *Cond << "\n");
+ // We are going to make essential changes to CFG. This may invalidate cached
+ // information for L or one of its parent loops in SCEV.
+ if (auto *SEWP = getAnalysisIfAvailable<ScalarEvolutionWrapperPass>())
+ SEWP->getSE().forgetTopmostLoop(L);
// First step, split the preheader, so that we know that there is a safe place
// to insert the conditional branch. We will change loopPreheader to have a
@@ -1038,7 +1043,7 @@ bool LoopUnswitch::TryTrivialLoopUnswitch(bool &Changed) {
// until it finds the trivial condition candidate (condition that is not a
// constant). Since unswitching generates branches with constant conditions,
// this scenario could be very common in practice.
- SmallSet<BasicBlock*, 8> Visited;
+ SmallPtrSet<BasicBlock*, 8> Visited;
while (true) {
// If we exit loop or reach a previous visited block, then
@@ -1196,13 +1201,15 @@ void LoopUnswitch::SplitExitEdges(Loop *L,
void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
Loop *L, TerminatorInst *TI) {
Function *F = loopHeader->getParent();
- DEBUG(dbgs() << "loop-unswitch: Unswitching loop %"
- << loopHeader->getName() << " [" << L->getBlocks().size()
- << " blocks] in Function " << F->getName()
- << " when '" << *Val << "' == " << *LIC << "\n");
+ LLVM_DEBUG(dbgs() << "loop-unswitch: Unswitching loop %"
+ << loopHeader->getName() << " [" << L->getBlocks().size()
+ << " blocks] in Function " << F->getName() << " when '"
+ << *Val << "' == " << *LIC << "\n");
+ // We are going to make essential changes to CFG. This may invalidate cached
+ // information for L or one of its parent loops in SCEV.
if (auto *SEWP = getAnalysisIfAvailable<ScalarEvolutionWrapperPass>())
- SEWP->getSE().forgetLoop(L);
+ SEWP->getSE().forgetTopmostLoop(L);
LoopBlocks.clear();
NewBlocks.clear();
@@ -1274,12 +1281,11 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
// If the successor of the exit block had PHI nodes, add an entry for
// NewExit.
- for (BasicBlock::iterator I = ExitSucc->begin();
- PHINode *PN = dyn_cast<PHINode>(I); ++I) {
- Value *V = PN->getIncomingValueForBlock(ExitBlocks[i]);
+ for (PHINode &PN : ExitSucc->phis()) {
+ Value *V = PN.getIncomingValueForBlock(ExitBlocks[i]);
ValueToValueMapTy::iterator It = VMap.find(V);
if (It != VMap.end()) V = It->second;
- PN->addIncoming(V, NewExit);
+ PN.addIncoming(V, NewExit);
}
if (LandingPadInst *LPad = NewExit->getLandingPadInst()) {
@@ -1356,7 +1362,7 @@ static void RemoveFromWorklist(Instruction *I,
static void ReplaceUsesOfWith(Instruction *I, Value *V,
std::vector<Instruction*> &Worklist,
Loop *L, LPPassManager *LPM) {
- DEBUG(dbgs() << "Replace with '" << *V << "': " << *I << "\n");
+ LLVM_DEBUG(dbgs() << "Replace with '" << *V << "': " << *I << "\n");
// Add uses to the worklist, which may be dead now.
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
@@ -1496,10 +1502,9 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC,
BranchInst::Create(Abort, OldSISucc,
ConstantInt::getTrue(Context), NewSISucc);
// Release the PHI operands for this edge.
- for (BasicBlock::iterator II = NewSISucc->begin();
- PHINode *PN = dyn_cast<PHINode>(II); ++II)
- PN->setIncomingValue(PN->getBasicBlockIndex(Switch),
- UndefValue::get(PN->getType()));
+ for (PHINode &PN : NewSISucc->phis())
+ PN.setIncomingValue(PN.getBasicBlockIndex(Switch),
+ UndefValue::get(PN.getType()));
// Tell the domtree about the new block. We don't fully update the
// domtree here -- instead we force it to do a full recomputation
// after the pass is complete -- but we do need to inform it of
@@ -1526,7 +1531,7 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) {
// Simple DCE.
if (isInstructionTriviallyDead(I)) {
- DEBUG(dbgs() << "Remove dead instruction '" << *I << "\n");
+ LLVM_DEBUG(dbgs() << "Remove dead instruction '" << *I << "\n");
// Add uses to the worklist, which may be dead now.
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
@@ -1559,8 +1564,8 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) {
if (!SinglePred) continue; // Nothing to do.
assert(SinglePred == Pred && "CFG broken");
- DEBUG(dbgs() << "Merging blocks: " << Pred->getName() << " <- "
- << Succ->getName() << "\n");
+ LLVM_DEBUG(dbgs() << "Merging blocks: " << Pred->getName() << " <- "
+ << Succ->getName() << "\n");
// Resolve any single entry PHI nodes in Succ.
while (PHINode *PN = dyn_cast<PHINode>(Succ->begin()))
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-07 11:34:09 +0000