diff options
Diffstat (limited to 'lib/Transforms/Utils/Local.cpp')
| -rw-r--r-- | lib/Transforms/Utils/Local.cpp | 69 |
1 files changed, 26 insertions, 43 deletions
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp index 3bdbaa5..0f6d9ae 100644 --- a/lib/Transforms/Utils/Local.cpp +++ b/lib/Transforms/Utils/Local.cpp @@ -427,10 +427,6 @@ void llvm::MergeBasicBlockIntoOnlyPred(BasicBlock *DestBB, Pass *P) { BasicBlock *PredBB = DestBB->getSinglePredecessor(); assert(PredBB && "Block doesn't have a single predecessor!"); - // Splice all the instructions from PredBB to DestBB. - PredBB->getTerminator()->eraseFromParent(); - DestBB->getInstList().splice(DestBB->begin(), PredBB->getInstList()); - // Zap anything that took the address of DestBB. Not doing this will give the // address an invalid value. if (DestBB->hasAddressTaken()) { @@ -445,6 +441,10 @@ void llvm::MergeBasicBlockIntoOnlyPred(BasicBlock *DestBB, Pass *P) { // Anything that branched to PredBB now branches to DestBB. PredBB->replaceAllUsesWith(DestBB); + // Splice all the instructions from PredBB to DestBB. + PredBB->getTerminator()->eraseFromParent(); + DestBB->getInstList().splice(DestBB->begin(), PredBB->getInstList()); + if (P) { DominatorTree *DT = P->getAnalysisIfAvailable<DominatorTree>(); if (DT) { @@ -536,9 +536,9 @@ static bool CanPropagatePredecessorsForPHIs(BasicBlock *BB, BasicBlock *Succ) { /// TryToSimplifyUncondBranchFromEmptyBlock - BB is known to contain an /// unconditional branch, and contains no instructions other than PHI nodes, -/// potential debug intrinsics and the branch. If possible, eliminate BB by -/// rewriting all the predecessors to branch to the successor block and return -/// true. If we can't transform, return false. +/// potential side-effect free intrinsics and the branch. If possible, +/// eliminate BB by rewriting all the predecessors to branch to the successor +/// block and return true. If we can't transform, return false. bool llvm::TryToSimplifyUncondBranchFromEmptyBlock(BasicBlock *BB) { assert(BB != &BB->getParent()->getEntryBlock() && "TryToSimplifyUncondBranchFromEmptyBlock called on entry block!"); @@ -613,13 +613,15 @@ bool llvm::TryToSimplifyUncondBranchFromEmptyBlock(BasicBlock *BB) { } } - while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) { - if (Succ->getSinglePredecessor()) { - // BB is the only predecessor of Succ, so Succ will end up with exactly - // the same predecessors BB had. - Succ->getInstList().splice(Succ->begin(), - BB->getInstList(), BB->begin()); - } else { + if (Succ->getSinglePredecessor()) { + // BB is the only predecessor of Succ, so Succ will end up with exactly + // the same predecessors BB had. + + // Copy over any phi, debug or lifetime instruction. + BB->getTerminator()->eraseFromParent(); + Succ->getInstList().splice(Succ->getFirstNonPHI(), BB->getInstList()); + } else { + while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) { // We explicitly check for such uses in CanPropagatePredecessorsForPHIs. assert(PN->use_empty() && "There shouldn't be any uses here!"); PN->eraseFromParent(); @@ -642,7 +644,7 @@ bool llvm::EliminateDuplicatePHINodes(BasicBlock *BB) { bool Changed = false; // This implementation doesn't currently consider undef operands - // specially. Theroetically, two phis which are identical except for + // specially. Theoretically, two phis which are identical except for // one having an undef where the other doesn't could be collapsed. // Map from PHI hash values to PHI nodes. If multiple PHIs have @@ -660,12 +662,17 @@ bool llvm::EliminateDuplicatePHINodes(BasicBlock *BB) { // them, which helps expose duplicates, but we have to check all the // operands to be safe in case instcombine hasn't run. uintptr_t Hash = 0; + // This hash algorithm is quite weak as hash functions go, but it seems + // to do a good enough job for this particular purpose, and is very quick. for (User::op_iterator I = PN->op_begin(), E = PN->op_end(); I != E; ++I) { - // This hash algorithm is quite weak as hash functions go, but it seems - // to do a good enough job for this particular purpose, and is very quick. Hash ^= reinterpret_cast<uintptr_t>(static_cast<Value *>(*I)); Hash = (Hash << 7) | (Hash >> (sizeof(uintptr_t) * CHAR_BIT - 7)); } + for (PHINode::block_iterator I = PN->block_begin(), E = PN->block_end(); + I != E; ++I) { + Hash ^= reinterpret_cast<uintptr_t>(static_cast<BasicBlock *>(*I)); + Hash = (Hash << 7) | (Hash >> (sizeof(uintptr_t) * CHAR_BIT - 7)); + } // Avoid colliding with the DenseMap sentinels ~0 and ~0-1. Hash >>= 1; // If we've never seen this hash value before, it's a unique PHI. @@ -706,39 +713,15 @@ bool llvm::EliminateDuplicatePHINodes(BasicBlock *BB) { /// static unsigned enforceKnownAlignment(Value *V, unsigned Align, unsigned PrefAlign) { + V = V->stripPointerCasts(); - User *U = dyn_cast<User>(V); - if (!U) return Align; - - switch (Operator::getOpcode(U)) { - default: break; - case Instruction::BitCast: - return enforceKnownAlignment(U->getOperand(0), Align, PrefAlign); - case Instruction::GetElementPtr: { - // If all indexes are zero, it is just the alignment of the base pointer. - bool AllZeroOperands = true; - for (User::op_iterator i = U->op_begin() + 1, e = U->op_end(); i != e; ++i) - if (!isa<Constant>(*i) || - !cast<Constant>(*i)->isNullValue()) { - AllZeroOperands = false; - break; - } - - if (AllZeroOperands) { - // Treat this like a bitcast. - return enforceKnownAlignment(U->getOperand(0), Align, PrefAlign); - } - return Align; - } - case Instruction::Alloca: { - AllocaInst *AI = cast<AllocaInst>(V); + if (AllocaInst *AI = dyn_cast<AllocaInst>(V)) { // If there is a requested alignment and if this is an alloca, round up. if (AI->getAlignment() >= PrefAlign) return AI->getAlignment(); AI->setAlignment(PrefAlign); return PrefAlign; } - } if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) { // If there is a large requested alignment and we can, bump up the alignment |
