//
//===----------------------------------------------------------------------===//
-#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Scalar/EarlyCSE.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/ScopedHashTable.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Dominators.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/RecyclingAllocator.h"
-#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/Local.h"
#include <deque>
using namespace llvm;
STATISTIC(NumCSECall, "Number of call instructions CSE'd");
STATISTIC(NumDSE, "Number of trivial dead stores removed");
-static unsigned getHash(const void *V) {
- return DenseMapInfo<const void*>::getHashValue(V);
-}
-
//===----------------------------------------------------------------------===//
// SimpleValue
//===----------------------------------------------------------------------===//
unsigned DenseMapInfo<CallValue>::getHashValue(CallValue Val) {
Instruction *Inst = Val.Inst;
- // Hash in all of the operands as pointers.
- unsigned Res = 0;
- for (unsigned i = 0, e = Inst->getNumOperands(); i != e; ++i) {
- assert(!Inst->getOperand(i)->getType()->isMetadataTy() &&
- "Cannot value number calls with metadata operands");
- Res ^= getHash(Inst->getOperand(i)) << (i & 0xF);
- }
-
- // Mix in the opcode.
- return (Res << 1) ^ Inst->getOpcode();
+ // Hash all of the operands as pointers and mix in the opcode.
+ return hash_combine(
+ Inst->getOpcode(),
+ hash_combine_range(Inst->value_op_begin(), Inst->value_op_end()));
}
bool DenseMapInfo<CallValue>::isEqual(CallValue LHS, CallValue RHS) {
class EarlyCSE {
public:
Function &F;
- const DataLayout *DL;
const TargetLibraryInfo &TLI;
const TargetTransformInfo &TTI;
DominatorTree &DT;
unsigned CurrentGeneration;
/// \brief Set up the EarlyCSE runner for a particular function.
- EarlyCSE(Function &F, const DataLayout *DL, const TargetLibraryInfo &TLI,
+ EarlyCSE(Function &F, const TargetLibraryInfo &TLI,
const TargetTransformInfo &TTI, DominatorTree &DT,
AssumptionCache &AC)
- : F(F), DL(DL), TLI(TLI), TTI(TTI), DT(DT), AC(AC), CurrentGeneration(0) {
- }
+ : F(F), TLI(TLI), TTI(TTI), DT(DT), AC(AC), CurrentGeneration(0) {}
bool run();
CallScope(AvailableCalls) {}
private:
- NodeScope(const NodeScope &) LLVM_DELETED_FUNCTION;
- void operator=(const NodeScope &) LLVM_DELETED_FUNCTION;
+ NodeScope(const NodeScope &) = delete;
+ void operator=(const NodeScope &) = delete;
ScopedHTType::ScopeTy Scope;
LoadHTType::ScopeTy LoadScope;
void process() { Processed = true; }
private:
- StackNode(const StackNode &) LLVM_DELETED_FUNCTION;
- void operator=(const StackNode &) LLVM_DELETED_FUNCTION;
+ StackNode(const StackNode &) = delete;
+ void operator=(const StackNode &) = delete;
// Members.
unsigned CurrentGeneration;
if (!BB->getSinglePredecessor())
++CurrentGeneration;
+ // If this node has a single predecessor which ends in a conditional branch,
+ // we can infer the value of the branch condition given that we took this
+ // path. We need the single predeccesor to ensure there's not another path
+ // which reaches this block where the condition might hold a different
+ // value. Since we're adding this to the scoped hash table (like any other
+ // def), it will have been popped if we encounter a future merge block.
+ if (BasicBlock *Pred = BB->getSinglePredecessor())
+ if (auto *BI = dyn_cast<BranchInst>(Pred->getTerminator()))
+ if (BI->isConditional())
+ if (auto *CondInst = dyn_cast<Instruction>(BI->getCondition()))
+ if (SimpleValue::canHandle(CondInst)) {
+ assert(BI->getSuccessor(0) == BB || BI->getSuccessor(1) == BB);
+ auto *ConditionalConstant = (BI->getSuccessor(0) == BB) ?
+ ConstantInt::getTrue(BB->getContext()) :
+ ConstantInt::getFalse(BB->getContext());
+ AvailableValues.insert(CondInst, ConditionalConstant);
+ DEBUG(dbgs() << "EarlyCSE CVP: Add conditional value for '"
+ << CondInst->getName() << "' as " << *ConditionalConstant
+ << " in " << BB->getName() << "\n");
+ // Replace all dominated uses with the known value
+ replaceDominatedUsesWith(CondInst, ConditionalConstant, DT,
+ BasicBlockEdge(Pred, BB));
+ }
+
/// LastStore - Keep track of the last non-volatile store that we saw... for
/// as long as there in no instruction that reads memory. If we see a store
/// to the same location, we delete the dead store. This zaps trivial dead
Instruction *LastStore = nullptr;
bool Changed = false;
+ const DataLayout &DL = BB->getModule()->getDataLayout();
// See if any instructions in the block can be eliminated. If so, do it. If
// not, add them to AvailableValues.
// Ignore volatile loads.
if (MemInst.isVolatile()) {
LastStore = nullptr;
+ // Don't CSE across synchronization boundaries.
+ if (Inst->mayWriteToMemory())
+ ++CurrentGeneration;
continue;
}
return Changed;
}
+PreservedAnalyses EarlyCSEPass::run(Function &F,
+ AnalysisManager<Function> *AM) {
+ auto &TLI = AM->getResult<TargetLibraryAnalysis>(F);
+ auto &TTI = AM->getResult<TargetIRAnalysis>(F);
+ auto &DT = AM->getResult<DominatorTreeAnalysis>(F);
+ auto &AC = AM->getResult<AssumptionAnalysis>(F);
+
+ EarlyCSE CSE(F, TLI, TTI, DT, AC);
+
+ if (!CSE.run())
+ return PreservedAnalyses::all();
+
+ // CSE preserves the dominator tree because it doesn't mutate the CFG.
+ // FIXME: Bundle this with other CFG-preservation.
+ PreservedAnalyses PA;
+ PA.preserve<DominatorTreeAnalysis>();
+ return PA;
+}
+
namespace {
/// \brief A simple and fast domtree-based CSE pass.
///
if (skipOptnoneFunction(F))
return false;
- DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
- auto *DL = DLP ? &DLP->getDataLayout() : nullptr;
auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
- auto &TTI = getAnalysis<TargetTransformInfoWrapperPass>().getTTI();
+ auto &TTI = getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
- EarlyCSE CSE(F, DL, TLI, TTI, DT, AC);
+ EarlyCSE CSE(F, TLI, TTI, DT, AC);
return CSE.run();
}
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