X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FLoopInfo.cpp;h=05831402f4092bcea8ccf670e5864f8fdab03f40;hb=12bf43bc4f86602a5677d5e1662cb4e40562351b;hp=453af5a5555af83c8b3ea58eb8bd8d78f296a27d;hpb=dda30cd4af1c5f88fc00fd40b673f8e27c61379d;p=oota-llvm.git diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp index 453af5a5555..05831402f40 100644 --- a/lib/Analysis/LoopInfo.cpp +++ b/lib/Analysis/LoopInfo.cpp @@ -29,17 +29,18 @@ using namespace llvm; // Always verify loopinfo if expensive checking is enabled. #ifdef XDEBUG -bool VerifyLoopInfo = true; +static bool VerifyLoopInfo = true; #else -bool VerifyLoopInfo = false; +static bool VerifyLoopInfo = false; #endif static cl::opt VerifyLoopInfoX("verify-loop-info", cl::location(VerifyLoopInfo), cl::desc("Verify loop info (time consuming)")); char LoopInfo::ID = 0; -static RegisterPass -X("loops", "Natural Loop Information", true, true); +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 implementation @@ -49,15 +50,18 @@ X("loops", "Natural Loop Information", true, true); /// bool Loop::isLoopInvariant(Value *V) const { if (Instruction *I = dyn_cast(V)) - return isLoopInvariant(I); + return !contains(I); return true; // All non-instructions are loop invariant } -/// isLoopInvariant - Return true if the specified instruction is -/// loop-invariant. -/// -bool Loop::isLoopInvariant(Instruction *I) const { - return !contains(I); +/// hasLoopInvariantOperands - Return true if all the operands of the +/// specified instruction are loop invariant. +bool Loop::hasLoopInvariantOperands(Instruction *I) const { + for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) + if (!isLoopInvariant(I->getOperand(i))) + return false; + + return true; } /// makeLoopInvariant - If the given value is an instruciton inside of the @@ -106,6 +110,7 @@ bool Loop::makeLoopInvariant(Instruction *I, bool &Changed, for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) if (!makeLoopInvariant(I->getOperand(i), Changed, InsertPt)) return false; + // Hoist. I->moveBefore(InsertPt); Changed = true; @@ -124,14 +129,13 @@ PHINode *Loop::getCanonicalInductionVariable() const { BasicBlock *H = getHeader(); BasicBlock *Incoming = 0, *Backedge = 0; - typedef GraphTraits > InvBlockTraits; - InvBlockTraits::ChildIteratorType PI = InvBlockTraits::child_begin(H); - assert(PI != InvBlockTraits::child_end(H) && + pred_iterator PI = pred_begin(H); + assert(PI != pred_end(H) && "Loop must have at least one backedge!"); Backedge = *PI++; - if (PI == InvBlockTraits::child_end(H)) return 0; // dead loop + if (PI == pred_end(H)) return 0; // dead loop Incoming = *PI++; - if (PI != InvBlockTraits::child_end(H)) return 0; // multiple backedges? + if (PI != pred_end(H)) return 0; // multiple backedges? if (contains(Incoming)) { if (contains(Backedge)) @@ -157,18 +161,6 @@ PHINode *Loop::getCanonicalInductionVariable() const { return 0; } -/// getCanonicalInductionVariableIncrement - Return the LLVM value that holds -/// the canonical induction variable value for the "next" iteration of the -/// loop. This always succeeds if getCanonicalInductionVariable succeeds. -/// -Instruction *Loop::getCanonicalInductionVariableIncrement() const { - if (PHINode *PN = getCanonicalInductionVariable()) { - bool P1InLoop = contains(PN->getIncomingBlock(1)); - return cast(PN->getIncomingValue(P1InLoop)); - } - return 0; -} - /// getTripCount - Return a loop-invariant LLVM value indicating the number of /// times the loop will be executed. Note that this means that the backedge /// of the loop executes N-1 times. If the trip-count cannot be determined, @@ -180,12 +172,12 @@ Instruction *Loop::getCanonicalInductionVariableIncrement() const { Value *Loop::getTripCount() const { // Canonical loops will end with a 'cmp ne I, V', where I is the incremented // canonical induction variable and V is the trip count of the loop. - Instruction *Inc = getCanonicalInductionVariableIncrement(); - if (Inc == 0) return 0; - PHINode *IV = cast(Inc->getOperand(0)); + PHINode *IV = getCanonicalInductionVariable(); + if (IV == 0 || IV->getNumIncomingValues() != 2) return 0; - BasicBlock *BackedgeBlock = - IV->getIncomingBlock(contains(IV->getIncomingBlock(1))); + bool P0InLoop = contains(IV->getIncomingBlock(0)); + Value *Inc = IV->getIncomingValue(!P0InLoop); + BasicBlock *BackedgeBlock = IV->getIncomingBlock(!P0InLoop); if (BranchInst *BI = dyn_cast(BackedgeBlock->getTerminator())) if (BI->isConditional()) { @@ -206,7 +198,7 @@ Value *Loop::getTripCount() const { /// getSmallConstantTripCount - Returns the trip count of this loop as a /// normal unsigned value, if possible. Returns 0 if the trip count is unknown -/// of not constant. Will also return 0 if the trip count is very large +/// or not constant. Will also return 0 if the trip count is very large /// (>= 2^32) unsigned Loop::getSmallConstantTripCount() const { Value* TripCount = this->getTripCount(); @@ -263,23 +255,28 @@ unsigned Loop::getSmallConstantTripMultiple() const { } /// isLCSSAForm - Return true if the Loop is in LCSSA form -bool Loop::isLCSSAForm() const { +bool Loop::isLCSSAForm(DominatorTree &DT) const { // Sort the blocks vector so that we can use binary search to do quick // lookups. - SmallPtrSet LoopBBs(block_begin(), block_end()); + SmallPtrSet LoopBBs(block_begin(), block_end()); for (block_iterator BI = block_begin(), E = block_end(); BI != E; ++BI) { BasicBlock *BB = *BI; for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E;++I) for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; ++UI) { - BasicBlock *UserBB = cast(*UI)->getParent(); - if (PHINode *P = dyn_cast(*UI)) + User *U = *UI; + BasicBlock *UserBB = cast(U)->getParent(); + if (PHINode *P = dyn_cast(U)) UserBB = P->getIncomingBlock(UI); - // Check the current block, as a fast-path. Most values are used in - // the same block they are defined in. - if (UserBB != BB && !LoopBBs.count(UserBB)) + // Check the current block, as a fast-path, before checking whether + // the use is anywhere in the loop. Most values are used in the same + // block they are defined in. Also, blocks not reachable from the + // entry are special; uses in them don't need to go through PHIs. + if (UserBB != BB && + !LoopBBs.count(UserBB) && + DT.isReachableFromEntry(UserBB)) return false; } } @@ -336,16 +333,12 @@ Loop::getUniqueExitBlocks(SmallVectorImpl &ExitBlocks) const { BasicBlock *current = *BI; switchExitBlocks.clear(); - typedef GraphTraits BlockTraits; - typedef GraphTraits > InvBlockTraits; - for (BlockTraits::ChildIteratorType I = - BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI); - I != E; ++I) { + for (succ_iterator I = succ_begin(*BI), E = succ_end(*BI); I != E; ++I) { // If block is inside the loop then it is not a exit block. if (std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I)) continue; - InvBlockTraits::ChildIteratorType PI = InvBlockTraits::child_begin(*I); + pred_iterator PI = pred_begin(*I); BasicBlock *firstPred = *PI; // If current basic block is this exit block's first predecessor @@ -358,8 +351,7 @@ Loop::getUniqueExitBlocks(SmallVectorImpl &ExitBlocks) const { // If a terminator has more then two successors, for example SwitchInst, // then it is possible that there are multiple edges from current block // to one exit block. - if (std::distance(BlockTraits::child_begin(current), - BlockTraits::child_end(current)) <= 2) { + if (std::distance(succ_begin(current), succ_end(current)) <= 2) { ExitBlocks.push_back(*I); continue; }