//
//===----------------------------------------------------------------------===//
-#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Scalar/Sink.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Scalar.h"
using namespace llvm;
#define DEBUG_TYPE "sink"
STATISTIC(NumSunk, "Number of instructions sunk");
STATISTIC(NumSinkIter, "Number of sinking iterations");
-namespace {
- class Sinking : public FunctionPass {
- DominatorTree *DT;
- LoopInfo *LI;
- AliasAnalysis *AA;
-
- public:
- static char ID; // Pass identification
- Sinking() : FunctionPass(ID) {
- initializeSinkingPass(*PassRegistry::getPassRegistry());
- }
-
- bool runOnFunction(Function &F) override;
-
- void getAnalysisUsage(AnalysisUsage &AU) const override {
- AU.setPreservesCFG();
- FunctionPass::getAnalysisUsage(AU);
- AU.addRequired<AAResultsWrapperPass>();
- AU.addRequired<DominatorTreeWrapperPass>();
- AU.addRequired<LoopInfoWrapperPass>();
- AU.addPreserved<DominatorTreeWrapperPass>();
- AU.addPreserved<LoopInfoWrapperPass>();
- }
- private:
- bool ProcessBlock(BasicBlock &BB);
- bool SinkInstruction(Instruction *I, SmallPtrSetImpl<Instruction*> &Stores);
- bool AllUsesDominatedByBlock(Instruction *Inst, BasicBlock *BB) const;
- bool IsAcceptableTarget(Instruction *Inst, BasicBlock *SuccToSinkTo) const;
- };
-} // end anonymous namespace
-
-char Sinking::ID = 0;
-INITIALIZE_PASS_BEGIN(Sinking, "sink", "Code sinking", false, false)
-INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
-INITIALIZE_PASS_END(Sinking, "sink", "Code sinking", false, false)
-
-FunctionPass *llvm::createSinkingPass() { return new Sinking(); }
-
/// AllUsesDominatedByBlock - Return true if all uses of the specified value
/// occur in blocks dominated by the specified block.
-bool Sinking::AllUsesDominatedByBlock(Instruction *Inst,
- BasicBlock *BB) const {
+static bool AllUsesDominatedByBlock(Instruction *Inst, BasicBlock *BB,
+ DominatorTree &DT) {
// Ignoring debug uses is necessary so debug info doesn't affect the code.
// This may leave a referencing dbg_value in the original block, before
// the definition of the vreg. Dwarf generator handles this although the
UseBlock = PN->getIncomingBlock(Num);
}
// Check that it dominates.
- if (!DT->dominates(BB, UseBlock))
+ if (!DT.dominates(BB, UseBlock))
return false;
}
return true;
}
-static bool isSafeToMove(Instruction *Inst, AliasAnalysis *AA,
+static bool isSafeToMove(Instruction *Inst, AliasAnalysis &AA,
SmallPtrSetImpl<Instruction *> &Stores) {
if (Inst->mayWriteToMemory()) {
if (LoadInst *L = dyn_cast<LoadInst>(Inst)) {
MemoryLocation Loc = MemoryLocation::get(L);
for (Instruction *S : Stores)
- if (AA->getModRefInfo(S, Loc) & MRI_Mod)
+ if (AA.getModRefInfo(S, Loc) & MRI_Mod)
return false;
}
/// IsAcceptableTarget - Return true if it is possible to sink the instruction
/// in the specified basic block.
-bool Sinking::IsAcceptableTarget(Instruction *Inst,
- BasicBlock *SuccToSinkTo) const {
+static bool IsAcceptableTarget(Instruction *Inst, BasicBlock *SuccToSinkTo,
+ DominatorTree &DT, LoopInfo &LI) {
assert(Inst && "Instruction to be sunk is null");
assert(SuccToSinkTo && "Candidate sink target is null");
// We don't want to sink across a critical edge if we don't dominate the
// successor. We could be introducing calculations to new code paths.
- if (!DT->dominates(Inst->getParent(), SuccToSinkTo))
+ if (!DT.dominates(Inst->getParent(), SuccToSinkTo))
return false;
// Don't sink instructions into a loop.
- Loop *succ = LI->getLoopFor(SuccToSinkTo);
- Loop *cur = LI->getLoopFor(Inst->getParent());
+ Loop *succ = LI.getLoopFor(SuccToSinkTo);
+ Loop *cur = LI.getLoopFor(Inst->getParent());
if (succ != nullptr && succ != cur)
return false;
}
// Finally, check that all the uses of the instruction are actually
// dominated by the candidate
- return AllUsesDominatedByBlock(Inst, SuccToSinkTo);
+ return AllUsesDominatedByBlock(Inst, SuccToSinkTo, DT);
}
/// SinkInstruction - Determine whether it is safe to sink the specified machine
/// instruction out of its current block into a successor.
-bool Sinking::SinkInstruction(Instruction *Inst,
- SmallPtrSetImpl<Instruction *> &Stores) {
+static bool SinkInstruction(Instruction *Inst,
+ SmallPtrSetImpl<Instruction *> &Stores,
+ DominatorTree &DT, LoopInfo &LI, AAResults &AA) {
// Don't sink static alloca instructions. CodeGen assumes allocas outside the
// entry block are dynamically sized stack objects.
// Instructions can only be sunk if all their uses are in blocks
// dominated by one of the successors.
// Look at all the postdominators and see if we can sink it in one.
- DomTreeNode *DTN = DT->getNode(Inst->getParent());
+ DomTreeNode *DTN = DT.getNode(Inst->getParent());
for (DomTreeNode::iterator I = DTN->begin(), E = DTN->end();
I != E && SuccToSinkTo == nullptr; ++I) {
BasicBlock *Candidate = (*I)->getBlock();
if ((*I)->getIDom()->getBlock() == Inst->getParent() &&
- IsAcceptableTarget(Inst, Candidate))
+ IsAcceptableTarget(Inst, Candidate, DT, LI))
SuccToSinkTo = Candidate;
}
// decide which one we should sink to, if any.
for (succ_iterator I = succ_begin(Inst->getParent()),
E = succ_end(Inst->getParent()); I != E && !SuccToSinkTo; ++I) {
- if (IsAcceptableTarget(Inst, *I))
+ if (IsAcceptableTarget(Inst, *I, DT, LI))
SuccToSinkTo = *I;
}
return true;
}
-bool Sinking::ProcessBlock(BasicBlock &BB) {
+static bool ProcessBlock(BasicBlock &BB, DominatorTree &DT, LoopInfo &LI,
+ AAResults &AA) {
// Can't sink anything out of a block that has less than two successors.
if (BB.getTerminator()->getNumSuccessors() <= 1) return false;
// Don't bother sinking code out of unreachable blocks. In addition to being
// unprofitable, it can also lead to infinite looping, because in an
// unreachable loop there may be nowhere to stop.
- if (!DT->isReachableFromEntry(&BB)) return false;
+ if (!DT.isReachableFromEntry(&BB)) return false;
bool MadeChange = false;
if (isa<DbgInfoIntrinsic>(Inst))
continue;
- if (SinkInstruction(Inst, Stores)) {
+ if (SinkInstruction(Inst, Stores, DT, LI, AA)) {
++NumSunk;
MadeChange = true;
}
return MadeChange;
}
-bool Sinking::runOnFunction(Function &F) {
- DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
- LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
- AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
-
+static bool iterativelySinkInstructions(Function &F, DominatorTree &DT,
+ LoopInfo &LI, AAResults &AA) {
bool MadeChange, EverMadeChange = false;
do {
// Process all basic blocks.
for (Function::iterator I = F.begin(), E = F.end();
I != E; ++I)
- MadeChange |= ProcessBlock(*I);
+ MadeChange |= ProcessBlock(*I, DT, LI, AA);
EverMadeChange |= MadeChange;
NumSinkIter++;
} while (MadeChange);
return EverMadeChange;
}
+
+PreservedAnalyses SinkingPass::run(Function &F, AnalysisManager<Function> &AM) {
+ auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
+ auto &LI = AM.getResult<LoopAnalysis>(F);
+ auto &AA = AM.getResult<AAManager>(F);
+
+ if (!iterativelySinkInstructions(F, DT, LI, AA))
+ return PreservedAnalyses::all();
+
+ auto PA = PreservedAnalyses();
+ PA.preserve<DominatorTreeAnalysis>();
+ PA.preserve<LoopAnalysis>();
+ return PA;
+}
+
+namespace {
+ class SinkingLegacyPass : public FunctionPass {
+ public:
+ static char ID; // Pass identification
+ SinkingLegacyPass() : FunctionPass(ID) {
+ initializeSinkingLegacyPassPass(*PassRegistry::getPassRegistry());
+ }
+
+ bool runOnFunction(Function &F) override {
+ auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+ auto &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+ auto &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
+
+ return iterativelySinkInstructions(F, DT, LI, AA);
+ }
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.setPreservesCFG();
+ FunctionPass::getAnalysisUsage(AU);
+ AU.addRequired<AAResultsWrapperPass>();
+ AU.addRequired<DominatorTreeWrapperPass>();
+ AU.addRequired<LoopInfoWrapperPass>();
+ AU.addPreserved<DominatorTreeWrapperPass>();
+ AU.addPreserved<LoopInfoWrapperPass>();
+ }
+ };
+} // end anonymous namespace
+
+char SinkingLegacyPass::ID = 0;
+INITIALIZE_PASS_BEGIN(SinkingLegacyPass, "sink", "Code sinking", false, false)
+INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
+INITIALIZE_PASS_END(SinkingLegacyPass, "sink", "Code sinking", false, false)
+
+FunctionPass *llvm::createSinkingPass() { return new SinkingLegacyPass(); }