#define DEBUG_TYPE "licm"
#include "llvm/Transforms/Scalar.h"
-#include "llvm/Constants.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/IntrinsicInst.h"
-#include "llvm/Instructions.h"
-#include "llvm/LLVMContext.h"
+#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AliasSetTracker.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/LoopPass.h"
-#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Transforms/Utils/SSAUpdater.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Metadata.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/Debug.h"
-#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Utils/SSAUpdater.h"
#include <algorithm>
using namespace llvm;
///
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
- AU.addRequired<DominatorTree>();
+ AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<LoopInfo>();
AU.addRequiredID(LoopSimplifyID);
AU.addRequired<AliasAnalysis>();
AU.addRequired<TargetLibraryInfo>();
}
+ using llvm::Pass::doFinalization;
+
bool doFinalization() {
assert(LoopToAliasSetMap.empty() && "Didn't free loop alias sets");
return false;
LoopInfo *LI; // Current LoopInfo
DominatorTree *DT; // Dominator Tree for the current Loop.
- TargetData *TD; // TargetData for constant folding.
+ DataLayout *TD; // DataLayout for constant folding.
TargetLibraryInfo *TLI; // TargetLibraryInfo for constant folding.
// State that is updated as we process loops.
BasicBlock *Preheader; // The preheader block of the current loop...
Loop *CurLoop; // The current loop we are working on...
AliasSetTracker *CurAST; // AliasSet information for the current loop...
+ bool MayThrow; // The current loop contains an instruction which
+ // may throw, thus preventing code motion of
+ // instructions with side effects.
DenseMap<Loop*, AliasSetTracker*> LoopToAliasSetMap;
/// cloneBasicBlockAnalysis - Simple Analysis hook. Clone alias set info.
char LICM::ID = 0;
INITIALIZE_PASS_BEGIN(LICM, "licm", "Loop Invariant Code Motion", false, false)
-INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(LoopInfo)
INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
// Get our Loop and Alias Analysis information...
LI = &getAnalysis<LoopInfo>();
AA = &getAnalysis<AliasAnalysis>();
- DT = &getAnalysis<DominatorTree>();
+ DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
- TD = getAnalysisIfAvailable<TargetData>();
+ TD = getAnalysisIfAvailable<DataLayout>();
TLI = &getAnalysis<TargetLibraryInfo>();
CurAST = new AliasSetTracker(*AA);
CurAST->add(*BB); // Incorporate the specified basic block
}
+ MayThrow = false;
+ // TODO: We've already searched for instructions which may throw in subloops.
+ // We may want to reuse this information.
+ for (Loop::block_iterator BB = L->block_begin(), BBE = L->block_end();
+ (BB != BBE) && !MayThrow ; ++BB)
+ for (BasicBlock::iterator I = (*BB)->begin(), E = (*BB)->end();
+ (I != E) && !MayThrow; ++I)
+ MayThrow |= I->mayThrow();
+
// We want to visit all of the instructions in this loop... that are not parts
// of our subloops (they have already had their invariants hoisted out of
// their loop, into this loop, so there is no need to process the BODIES of
if (!FoundMod) return true;
}
- // FIXME: This should use mod/ref information to see if we can hoist or sink
- // the call.
+ // FIXME: This should use mod/ref information to see if we can hoist or
+ // sink the call.
return false;
}
- // Otherwise these instructions are hoistable/sinkable
- return isa<BinaryOperator>(I) || isa<CastInst>(I) ||
- isa<SelectInst>(I) || isa<GetElementPtrInst>(I) || isa<CmpInst>(I) ||
- isa<InsertElementInst>(I) || isa<ExtractElementInst>(I) ||
- isa<ShuffleVectorInst>(I);
+ // Only these instructions are hoistable/sinkable.
+ if (!isa<BinaryOperator>(I) && !isa<CastInst>(I) && !isa<SelectInst>(I) &&
+ !isa<GetElementPtrInst>(I) && !isa<CmpInst>(I) &&
+ !isa<InsertElementInst>(I) && !isa<ExtractElementInst>(I) &&
+ !isa<ShuffleVectorInst>(I) && !isa<ExtractValueInst>(I) &&
+ !isa<InsertValueInst>(I))
+ return false;
+
+ return isSafeToExecuteUnconditionally(I);
}
/// isNotUsedInLoop - Return true if the only users of this instruction are
}
bool LICM::isGuaranteedToExecute(Instruction &Inst) {
+
+ // Somewhere in this loop there is an instruction which may throw and make us
+ // exit the loop.
+ if (MayThrow)
+ return false;
+
// Otherwise we have to check to make sure that the instruction dominates all
// of the exit blocks. If it doesn't, then there is a path out of the loop
// which does not execute this instruction, so we can't hoist it.
AliasSetTracker &AST;
DebugLoc DL;
int Alignment;
+ MDNode *TBAATag;
public:
LoopPromoter(Value *SP,
const SmallVectorImpl<Instruction*> &Insts, SSAUpdater &S,
SmallPtrSet<Value*, 4> &PMA,
SmallVectorImpl<BasicBlock*> &LEB,
SmallVectorImpl<Instruction*> &LIP,
- AliasSetTracker &ast, DebugLoc dl, int alignment)
+ AliasSetTracker &ast, DebugLoc dl, int alignment,
+ MDNode *TBAATag)
: LoadAndStorePromoter(Insts, S), SomePtr(SP),
PointerMustAliases(PMA), LoopExitBlocks(LEB), LoopInsertPts(LIP),
- AST(ast), DL(dl), Alignment(alignment) {}
+ AST(ast), DL(dl), Alignment(alignment), TBAATag(TBAATag) {}
virtual bool isInstInList(Instruction *I,
const SmallVectorImpl<Instruction*> &) const {
StoreInst *NewSI = new StoreInst(LiveInValue, SomePtr, InsertPos);
NewSI->setAlignment(Alignment);
NewSI->setDebugLoc(DL);
+ if (TBAATag) NewSI->setMetadata(LLVMContext::MD_tbaa, TBAATag);
}
}
// We start with an alignment of one and try to find instructions that allow
// us to prove better alignment.
unsigned Alignment = 1;
+ MDNode *TBAATag = 0;
// Check that all of the pointers in the alias set have the same type. We
// cannot (yet) promote a memory location that is loaded and stored in
- // different sizes.
+ // different sizes. While we are at it, collect alignment and TBAA info.
for (AliasSet::iterator ASI = AS.begin(), E = AS.end(); ASI != E; ++ASI) {
Value *ASIV = ASI->getValue();
PointerMustAliases.insert(ASIV);
// instruction will be executed, update the alignment.
// Larger is better, with the exception of 0 being the best alignment.
unsigned InstAlignment = store->getAlignment();
- if ((InstAlignment > Alignment || InstAlignment == 0)
- && (Alignment != 0))
+ if ((InstAlignment > Alignment || InstAlignment == 0) && Alignment != 0)
if (isGuaranteedToExecute(*Use)) {
GuaranteedToExecute = true;
Alignment = InstAlignment;
} else
return; // Not a load or store.
+ // Merge the TBAA tags.
+ if (LoopUses.empty()) {
+ // On the first load/store, just take its TBAA tag.
+ TBAATag = Use->getMetadata(LLVMContext::MD_tbaa);
+ } else if (TBAATag) {
+ TBAATag = MDNode::getMostGenericTBAA(TBAATag,
+ Use->getMetadata(LLVMContext::MD_tbaa));
+ }
+
LoopUses.push_back(Use);
}
}
SmallVector<PHINode*, 16> NewPHIs;
SSAUpdater SSA(&NewPHIs);
LoopPromoter Promoter(SomePtr, LoopUses, SSA, PointerMustAliases, ExitBlocks,
- InsertPts, *CurAST, DL, Alignment);
+ InsertPts, *CurAST, DL, Alignment, TBAATag);
// Set up the preheader to have a definition of the value. It is the live-out
// value from the preheader that uses in the loop will use.
Preheader->getTerminator());
PreheaderLoad->setAlignment(Alignment);
PreheaderLoad->setDebugLoc(DL);
+ if (TBAATag) PreheaderLoad->setMetadata(LLVMContext::MD_tbaa, TBAATag);
SSA.AddAvailableValue(Preheader, PreheaderLoad);
// Rewrite all the loads in the loop and remember all the definitions from
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