X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FLoopInfo.cpp;h=142ebed4ed7cfcba8605c3d74a789d1d923d68b2;hb=630d17566793c7f25a05cd407ab9b79a1756966a;hp=20c33a3d9d61834994b79e03e8ad3c37108bf71b;hpb=c9b1e25493b393013b28e5d457f2fb2845a4dd9f;p=oota-llvm.git diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp index 20c33a3d9d6..142ebed4ed7 100644 --- a/lib/Analysis/LoopInfo.cpp +++ b/lib/Analysis/LoopInfo.cpp @@ -15,18 +15,19 @@ //===----------------------------------------------------------------------===// #include "llvm/Analysis/LoopInfo.h" -#include "llvm/Constants.h" -#include "llvm/Instructions.h" +#include "llvm/ADT/DepthFirstIterator.h" +#include "llvm/ADT/SmallPtrSet.h" #include "llvm/Analysis/Dominators.h" #include "llvm/Analysis/LoopInfoImpl.h" #include "llvm/Analysis/LoopIterator.h" #include "llvm/Analysis/ValueTracking.h" #include "llvm/Assembly/Writer.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/Metadata.h" #include "llvm/Support/CFG.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" -#include "llvm/ADT/DepthFirstIterator.h" -#include "llvm/ADT/SmallPtrSet.h" #include using namespace llvm; @@ -49,6 +50,9 @@ INITIALIZE_PASS_BEGIN(LoopInfo, "loops", "Natural Loop Information", true, true) INITIALIZE_PASS_DEPENDENCY(DominatorTree) INITIALIZE_PASS_END(LoopInfo, "loops", "Natural Loop Information", true, true) +// Loop identifier metadata name. +static const char *const LoopMDName = "llvm.loop"; + //===----------------------------------------------------------------------===// // Loop implementation // @@ -213,14 +217,123 @@ bool Loop::isLoopSimplifyForm() const { /// isSafeToClone - Return true if the loop body is safe to clone in practice. /// Routines that reform the loop CFG and split edges often fail on indirectbr. bool Loop::isSafeToClone() const { - // Return false if any loop blocks contain indirectbrs. + // Return false if any loop blocks contain indirectbrs, or there are any calls + // to noduplicate functions. for (Loop::block_iterator I = block_begin(), E = block_end(); I != E; ++I) { - if (isa((*I)->getTerminator())) + if (isa((*I)->getTerminator())) { return false; + } else if (const InvokeInst *II = dyn_cast((*I)->getTerminator())) { + if (II->hasFnAttr(Attribute::NoDuplicate)) + return false; + } + + for (BasicBlock::iterator BI = (*I)->begin(), BE = (*I)->end(); BI != BE; ++BI) { + if (const CallInst *CI = dyn_cast(BI)) { + if (CI->hasFnAttr(Attribute::NoDuplicate)) + return false; + } + } } return true; } +MDNode *Loop::getLoopID() const { + MDNode *LoopID = 0; + if (isLoopSimplifyForm()) { + LoopID = getLoopLatch()->getTerminator()->getMetadata(LoopMDName); + } else { + // Go through each predecessor of the loop header and check the + // terminator for the metadata. + BasicBlock *H = getHeader(); + for (block_iterator I = block_begin(), IE = block_end(); I != IE; ++I) { + TerminatorInst *TI = (*I)->getTerminator(); + MDNode *MD = 0; + + // Check if this terminator branches to the loop header. + for (unsigned i = 0, ie = TI->getNumSuccessors(); i != ie; ++i) { + if (TI->getSuccessor(i) == H) { + MD = TI->getMetadata(LoopMDName); + break; + } + } + if (!MD) + return 0; + + if (!LoopID) + LoopID = MD; + else if (MD != LoopID) + return 0; + } + } + if (!LoopID || LoopID->getNumOperands() == 0 || + LoopID->getOperand(0) != LoopID) + return 0; + return LoopID; +} + +void Loop::setLoopID(MDNode *LoopID) const { + assert(LoopID && "Loop ID should not be null"); + assert(LoopID->getNumOperands() > 0 && "Loop ID needs at least one operand"); + assert(LoopID->getOperand(0) == LoopID && "Loop ID should refer to itself"); + + if (isLoopSimplifyForm()) { + getLoopLatch()->getTerminator()->setMetadata(LoopMDName, LoopID); + return; + } + + BasicBlock *H = getHeader(); + for (block_iterator I = block_begin(), IE = block_end(); I != IE; ++I) { + TerminatorInst *TI = (*I)->getTerminator(); + for (unsigned i = 0, ie = TI->getNumSuccessors(); i != ie; ++i) { + if (TI->getSuccessor(i) == H) + TI->setMetadata(LoopMDName, LoopID); + } + } +} + +bool Loop::isAnnotatedParallel() const { + MDNode *desiredLoopIdMetadata = getLoopID(); + + if (!desiredLoopIdMetadata) + return false; + + // The loop branch contains the parallel loop metadata. In order to ensure + // that any parallel-loop-unaware optimization pass hasn't added loop-carried + // dependencies (thus converted the loop back to a sequential loop), check + // that all the memory instructions in the loop contain parallelism metadata + // that point to the same unique "loop id metadata" the loop branch does. + for (block_iterator BB = block_begin(), BE = block_end(); BB != BE; ++BB) { + for (BasicBlock::iterator II = (*BB)->begin(), EE = (*BB)->end(); + II != EE; II++) { + + if (!II->mayReadOrWriteMemory()) + continue; + + if (!II->getMetadata("llvm.mem.parallel_loop_access")) + return false; + + // The memory instruction can refer to the loop identifier metadata + // directly or indirectly through another list metadata (in case of + // nested parallel loops). The loop identifier metadata refers to + // itself so we can check both cases with the same routine. + MDNode *loopIdMD = + dyn_cast(II->getMetadata("llvm.mem.parallel_loop_access")); + bool loopIdMDFound = false; + for (unsigned i = 0, e = loopIdMD->getNumOperands(); i < e; ++i) { + if (loopIdMD->getOperand(i) == desiredLoopIdMetadata) { + loopIdMDFound = true; + break; + } + } + + if (!loopIdMDFound) + return false; + } + } + return true; +} + + /// hasDedicatedExits - Return true if no exit block for the loop /// has a predecessor that is outside the loop. bool Loop::hasDedicatedExits() const { @@ -306,9 +419,11 @@ BasicBlock *Loop::getUniqueExitBlock() const { return 0; } +#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) void Loop::dump() const { print(dbgs()); } +#endif //===----------------------------------------------------------------------===// // UnloopUpdater implementation @@ -429,8 +544,8 @@ void UnloopUpdater::updateSubloopParents() { Unloop->removeChildLoop(llvm::prior(Unloop->end())); assert(SubloopParents.count(Subloop) && "DFS failed to visit subloop"); - if (SubloopParents[Subloop]) - SubloopParents[Subloop]->addChildLoop(Subloop); + if (Loop *Parent = SubloopParents[Subloop]) + Parent->addChildLoop(Subloop); else LI->addTopLevelLoop(Subloop); } @@ -456,9 +571,8 @@ Loop *UnloopUpdater::getNearestLoop(BasicBlock *BB, Loop *BBLoop) { assert(Subloop && "subloop is not an ancestor of the original loop"); } // Get the current nearest parent of the Subloop exits, initially Unloop. - if (!SubloopParents.count(Subloop)) - SubloopParents[Subloop] = Unloop; - NearLoop = SubloopParents[Subloop]; + NearLoop = + SubloopParents.insert(std::make_pair(Subloop, Unloop)).first->second; } succ_iterator I = succ_begin(BB), E = succ_end(BB);