#include "llvm/IR/DataLayout.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Metadata.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
TLI = &getAnalysis<TargetLibraryInfo>();
LVI = &getAnalysis<LazyValueInfo>();
+ // Remove unreachable blocks from function as they may result in infinite
+ // loop. We do threading if we found something profitable. Jump threading a
+ // branch can create other opportunities. If these opportunities form a cycle
+ // i.e. if any jump treading is undoing previous threading in the path, then
+ // we will loop forever. We take care of this issue by not jump threading for
+ // back edges. This works for normal cases but not for unreachable blocks as
+ // they may have cycle with no back edge.
+ removeUnreachableBlocks(F);
+
FindLoopHeaders(F);
bool Changed, EverChanged = false;
if (LoopHeaders.erase(SinglePred))
LoopHeaders.insert(BB);
- // Remember if SinglePred was the entry block of the function. If so, we
- // will need to move BB back to the entry position.
- bool isEntry = SinglePred == &SinglePred->getParent()->getEntryBlock();
LVI->eraseBlock(SinglePred);
MergeBasicBlockIntoOnlyPred(BB);
- if (isEntry && BB != &BB->getParent()->getEntryBlock())
- BB->moveBefore(&BB->getParent()->getEntryBlock());
return true;
}
}
if (BBIt != LoadBB->begin())
return false;
- // If all of the loads and stores that feed the value have the same TBAA tag,
- // then we can propagate it onto any newly inserted loads.
- MDNode *TBAATag = LI->getMetadata(LLVMContext::MD_tbaa);
+ // If all of the loads and stores that feed the value have the same AA tags,
+ // then we can propagate them onto any newly inserted loads.
+ AAMDNodes AATags;
+ LI->getAAMetadata(AATags);
SmallPtrSet<BasicBlock*, 8> PredsScanned;
typedef SmallVector<std::pair<BasicBlock*, Value*>, 8> AvailablePredsTy;
// Scan the predecessor to see if the value is available in the pred.
BBIt = PredBB->end();
- MDNode *ThisTBAATag = nullptr;
+ AAMDNodes ThisAATags;
Value *PredAvailable = FindAvailableLoadedValue(LoadedPtr, PredBB, BBIt, 6,
- nullptr, &ThisTBAATag);
+ nullptr, &ThisAATags);
if (!PredAvailable) {
OneUnavailablePred = PredBB;
continue;
}
- // If tbaa tags disagree or are not present, forget about them.
- if (TBAATag != ThisTBAATag) TBAATag = nullptr;
+ // If AA tags disagree or are not present, forget about them.
+ if (AATags != ThisAATags) AATags = AAMDNodes();
// If so, this load is partially redundant. Remember this info so that we
// can create a PHI node.
LI->getAlignment(),
UnavailablePred->getTerminator());
NewVal->setDebugLoc(LI->getDebugLoc());
- if (TBAATag)
- NewVal->setMetadata(LLVMContext::MD_tbaa, TBAATag);
+ if (AATags)
+ NewVal->setAAMetadata(AATags);
AvailablePreds.push_back(std::make_pair(UnavailablePred, NewVal));
}