#define DEBUG_TYPE "mem2reg"
#include "llvm/Transforms/Utils/PromoteMemToReg.h"
-#include "llvm/Constants.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Function.h"
-#include "llvm/Instructions.h"
-#include "llvm/IntrinsicInst.h"
-#include "llvm/Metadata.h"
-#include "llvm/Analysis/AliasSetTracker.h"
-#include "llvm/Analysis/DebugInfo.h"
-#include "llvm/Analysis/DominanceFrontier.h"
-#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Hashing.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/AliasSetTracker.h"
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/DIBuilder.h"
+#include "llvm/DebugInfo.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Metadata.h"
#include "llvm/Support/CFG.h"
+#include "llvm/Transforms/Utils/Local.h"
#include <algorithm>
#include <queue>
using namespace llvm;
return EltTy(reinterpret_cast<BasicBlock*>(-2), 0U);
}
static unsigned getHashValue(const std::pair<BasicBlock*, unsigned> &Val) {
- return DenseMapInfo<void*>::getHashValue(Val.first) + Val.second*2;
+ using llvm::hash_value;
+ return static_cast<unsigned>(hash_value(Val));
}
static bool isEqual(const EltTy &LHS, const EltTy &RHS) {
return LHS == RHS;
UI != UE; ++UI) { // Loop over all of the uses of the alloca
const User *U = *UI;
if (const LoadInst *LI = dyn_cast<LoadInst>(U)) {
+ // Note that atomic loads can be transformed; atomic semantics do
+ // not have any meaning for a local alloca.
if (LI->isVolatile())
return false;
} else if (const StoreInst *SI = dyn_cast<StoreInst>(U)) {
if (SI->getOperand(0) == AI)
return false; // Don't allow a store OF the AI, only INTO the AI.
+ // Note that atomic stores can be transformed; atomic semantics do
+ // not have any meaning for a local alloca.
if (SI->isVolatile())
return false;
+ } else if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(U)) {
+ if (II->getIntrinsicID() != Intrinsic::lifetime_start &&
+ II->getIntrinsicID() != Intrinsic::lifetime_end)
+ return false;
+ } else if (const BitCastInst *BCI = dyn_cast<BitCastInst>(U)) {
+ if (BCI->getType() != Type::getInt8PtrTy(U->getContext()))
+ return false;
+ if (!onlyUsedByLifetimeMarkers(BCI))
+ return false;
+ } else if (const GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(U)) {
+ if (GEPI->getType() != Type::getInt8PtrTy(U->getContext()))
+ return false;
+ if (!GEPI->hasAllZeroIndices())
+ return false;
+ if (!onlyUsedByLifetimeMarkers(GEPI))
+ return false;
} else {
return false;
}
return true;
}
-/// FindAllocaDbgDeclare - Finds the llvm.dbg.declare intrinsic describing the
-/// alloca 'V', if any.
-static DbgDeclareInst *FindAllocaDbgDeclare(Value *V) {
- if (MDNode *DebugNode = MDNode::getIfExists(V->getContext(), &V, 1))
- for (Value::use_iterator UI = DebugNode->use_begin(),
- E = DebugNode->use_end(); UI != E; ++UI)
- if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(*UI))
- return DDI;
-
- return 0;
-}
-
namespace {
struct AllocaInfo;
///
std::vector<AllocaInst*> Allocas;
DominatorTree &DT;
- DIFactory *DIF;
+ DIBuilder *DIB;
/// AST - An AliasSetTracker object to update. If null, don't update it.
///
/// AllocaLookup - Reverse mapping of Allocas.
///
-
std::map<AllocaInst*, unsigned> AllocaLookup;
+
DenseMap<AllocaInst*, unsigned> AllocaLookup;
- /// NewPhiNodes - The PhiNodes we're adding.
+ /// NewPhiNodes - The PhiNodes we're adding. That map is used to simplify
+ /// some Phi nodes as we iterate over it, so it should have deterministic
+ /// iterators. We could use a MapVector, but since we already maintain a
+ /// map from BasicBlock* to a stable numbering (BBNumbers), the DenseMap is
+ /// more efficient (also supports removal).
///
- DenseMap<std::pair<BasicBlock*, unsigned>, PHINode*> NewPhiNodes;
+ DenseMap<std::pair<unsigned, unsigned>, PHINode*> NewPhiNodes;
/// PhiToAllocaMap - For each PHI node, keep track of which entry in Allocas
/// it corresponds to.
public:
PromoteMem2Reg(const std::vector<AllocaInst*> &A, DominatorTree &dt,
AliasSetTracker *ast)
- : Allocas(A), DT(dt), DIF(0), AST(ast) {}
+ : Allocas(A), DT(dt), DIB(0), AST(ast) {}
~PromoteMem2Reg() {
- delete DIF;
+ delete DIB;
}
void run();
LargeBlockInfo &LBI);
void PromoteSingleBlockAlloca(AllocaInst *AI, AllocaInfo &Info,
LargeBlockInfo &LBI);
- void ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI, StoreInst *SI);
-
void RenamePass(BasicBlock *BB, BasicBlock *Pred,
RenamePassData::ValVector &IncVals,
};
struct AllocaInfo {
- std::vector<BasicBlock*> DefiningBlocks;
- std::vector<BasicBlock*> UsingBlocks;
+ SmallVector<BasicBlock*, 32> DefiningBlocks;
+ SmallVector<BasicBlock*, 32> UsingBlocks;
StoreInst *OnlyStore;
BasicBlock *OnlyBlock;
};
} // end of anonymous namespace
+static void removeLifetimeIntrinsicUsers(AllocaInst *AI) {
+ // Knowing that this alloca is promotable, we know that it's safe to kill all
+ // instructions except for load and store.
+
+ for (Value::use_iterator UI = AI->use_begin(), UE = AI->use_end();
+ UI != UE;) {
+ Instruction *I = cast<Instruction>(*UI);
+ ++UI;
+ if (isa<LoadInst>(I) || isa<StoreInst>(I))
+ continue;
+
+ if (!I->getType()->isVoidTy()) {
+ // The only users of this bitcast/GEP instruction are lifetime intrinsics.
+ // Follow the use/def chain to erase them now instead of leaving it for
+ // dead code elimination later.
+ for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
+ UI != UE;) {
+ Instruction *Inst = cast<Instruction>(*UI);
+ ++UI;
+ Inst->eraseFromParent();
+ }
+ }
+ I->eraseFromParent();
+ }
+}
void PromoteMem2Reg::run() {
Function &F = *DT.getRoot()->getParent();
assert(AI->getParent()->getParent() == &F &&
"All allocas should be in the same function, which is same as DF!");
+ removeLifetimeIntrinsicUsers(AI);
+
if (AI->use_empty()) {
// If there are no uses of the alloca, just delete it now.
if (AST) AST->deleteValue(AI);
// Finally, after the scan, check to see if the store is all that is left.
if (Info.UsingBlocks.empty()) {
- // Record debuginfo for the store and remove the declaration's debuginfo.
+ // Record debuginfo for the store and remove the declaration's
+ // debuginfo.
if (DbgDeclareInst *DDI = Info.DbgDeclare) {
- ConvertDebugDeclareToDebugValue(DDI, Info.OnlyStore);
+ if (!DIB)
+ DIB = new DIBuilder(*DDI->getParent()->getParent()->getParent());
+ ConvertDebugDeclareToDebugValue(DDI, Info.OnlyStore, *DIB);
DDI->eraseFromParent();
}
// Remove the (now dead) store and alloca.
while (!AI->use_empty()) {
StoreInst *SI = cast<StoreInst>(AI->use_back());
// Record debuginfo for the store before removing it.
- if (DbgDeclareInst *DDI = Info.DbgDeclare)
- ConvertDebugDeclareToDebugValue(DDI, SI);
+ if (DbgDeclareInst *DDI = Info.DbgDeclare) {
+ if (!DIB)
+ DIB = new DIBuilder(*SI->getParent()->getParent()->getParent());
+ ConvertDebugDeclareToDebugValue(DDI, SI, *DIB);
+ }
SI->eraseFromParent();
LBI.deleteValue(SI);
}
Instruction *A = Allocas[i];
// If there are any uses of the alloca instructions left, they must be in
- // sections of dead code that were not processed on the dominance frontier.
- // Just delete the users now.
- //
+ // unreachable basic blocks that were not processed by walking the dominator
+ // tree. Just delete the users now.
if (!A->use_empty())
A->replaceAllUsesWith(UndefValue::get(A->getType()));
if (AST) AST->deleteValue(A);
while (EliminatedAPHI) {
EliminatedAPHI = false;
- for (DenseMap<std::pair<BasicBlock*, unsigned>, PHINode*>::iterator I =
+ // Iterating over NewPhiNodes is deterministic, so it is safe to try to
+ // simplify and RAUW them as we go. If it was not, we could add uses to
+ // the values we replace with in a non deterministic order, thus creating
+ // non deterministic def->use chains.
+ for (DenseMap<std::pair<unsigned, unsigned>, PHINode*>::iterator I =
NewPhiNodes.begin(), E = NewPhiNodes.end(); I != E;) {
PHINode *PN = I->second;
// If this PHI node merges one value and/or undefs, get the value.
- if (Value *V = SimplifyInstruction(PN, 0, &DT)) {
+ if (Value *V = SimplifyInstruction(PN, 0, 0, &DT)) {
if (AST && PN->getType()->isPointerTy())
AST->deleteValue(PN);
PN->replaceAllUsesWith(V);
// have incoming values for all predecessors. Loop over all PHI nodes we have
// created, inserting undef values if they are missing any incoming values.
//
- for (DenseMap<std::pair<BasicBlock*, unsigned>, PHINode*>::iterator I =
+ for (DenseMap<std::pair<unsigned, unsigned>, PHINode*>::iterator I =
NewPhiNodes.begin(), E = NewPhiNodes.end(); I != E; ++I) {
// We want to do this once per basic block. As such, only process a block
// when we find the PHI that is the first entry in the block.
PQ.push(std::make_pair(Node, DomLevels[Node]));
}
- std::vector<std::pair<unsigned, BasicBlock*> > DFBlocks;
+ SmallVector<std::pair<unsigned, BasicBlock*>, 32> DFBlocks;
SmallPtrSet<DomTreeNode*, 32> Visited;
SmallVector<DomTreeNode*, 32> Worklist;
while (!PQ.empty()) {
}
}
-// Inserts a llvm.dbg.value instrinsic before the stores to an alloca'd value
-// that has an associated llvm.dbg.decl intrinsic.
-void PromoteMem2Reg::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
- StoreInst *SI) {
- DIVariable DIVar(DDI->getVariable());
- if (!DIVar.Verify())
- return;
-
- if (!DIF)
- DIF = new DIFactory(*SI->getParent()->getParent()->getParent());
- Instruction *DbgVal = DIF->InsertDbgValueIntrinsic(SI->getOperand(0), 0,
- DIVar, SI);
-
- // Propagate any debug metadata from the store onto the dbg.value.
- DebugLoc SIDL = SI->getDebugLoc();
- if (!SIDL.isUnknown())
- DbgVal->setDebugLoc(SIDL);
- // Otherwise propagate debug metadata from dbg.declare.
- else
- DbgVal->setDebugLoc(DDI->getDebugLoc());
-}
-
// QueuePhiNode - queues a phi-node to be added to a basic-block for a specific
// Alloca returns true if there wasn't already a phi-node for that variable
//
bool PromoteMem2Reg::QueuePhiNode(BasicBlock *BB, unsigned AllocaNo,
unsigned &Version) {
// Look up the basic-block in question.
- PHINode *&PN = NewPhiNodes[std::make_pair(BB, AllocaNo)];
+ PHINode *&PN = NewPhiNodes[std::make_pair(BBNumbers[BB], AllocaNo)];
// If the BB already has a phi node added for the i'th alloca then we're done!
if (PN) return false;
// Create a PhiNode using the dereferenced type... and add the phi-node to the
// BasicBlock.
- PN = PHINode::Create(Allocas[AllocaNo]->getAllocatedType(),
+ PN = PHINode::Create(Allocas[AllocaNo]->getAllocatedType(), getNumPreds(BB),
Allocas[AllocaNo]->getName() + "." + Twine(Version++),
BB->begin());
++NumPHIInsert;
PhiToAllocaMap[PN] = AllocaNo;
- PN->reserveOperandSpace(getNumPreds(BB));
if (AST && PN->getType()->isPointerTy())
AST->copyValue(PointerAllocaValues[AllocaNo], PN);
AllocaInst *Src = dyn_cast<AllocaInst>(LI->getPointerOperand());
if (!Src) continue;
-
std::map<AllocaInst*, unsigned>::iterator AI = AllocaLookup.find(Src);
+
DenseMap<AllocaInst*, unsigned>::iterator AI = AllocaLookup.find(Src);
if (AI == AllocaLookup.end()) continue;
Value *V = IncomingVals[AI->second];
AllocaInst *Dest = dyn_cast<AllocaInst>(SI->getPointerOperand());
if (!Dest) continue;
-
std::map<AllocaInst *, unsigned>::iterator ai = AllocaLookup.find(Dest);
+
DenseMap<AllocaInst *, unsigned>::iterator ai = AllocaLookup.find(Dest);
if (ai == AllocaLookup.end())
continue;
// what value were we writing?
IncomingVals[ai->second] = SI->getOperand(0);
// Record debuginfo for the store before removing it.
- if (DbgDeclareInst *DDI = AllocaDbgDeclares[ai->second])
- ConvertDebugDeclareToDebugValue(DDI, SI);
+ if (DbgDeclareInst *DDI = AllocaDbgDeclares[ai->second]) {
+ if (!DIB)
+ DIB = new DIBuilder(*SI->getParent()->getParent()->getParent());
+ ConvertDebugDeclareToDebugValue(DDI, SI, *DIB);
+ }
BB->getInstList().erase(SI);
}
}
}
/// PromoteMemToReg - Promote the specified list of alloca instructions into
-/// scalar registers, inserting PHI nodes as appropriate. This function makes
-/// use of DominanceFrontier information. This function does not modify the CFG
-/// of the function at all. All allocas must be from the same function.
+/// scalar registers, inserting PHI nodes as appropriate. This function does
+/// not modify the CFG of the function at all. All allocas must be from the
+/// same function.
///
/// If AST is specified, the specified tracker is updated to reflect changes
/// made to the IR.
projects / oota-llvm.git / blobdiff