if (II->getIntrinsicID() == Intrinsic::lifetime_start ||
II->getIntrinsicID() == Intrinsic::lifetime_end)
return isa<UndefValue>(II->getArgOperand(1));
+
+ // Assumptions are dead if their condition is trivially true.
+ if (II->getIntrinsicID() == Intrinsic::assume) {
+ if (ConstantInt *Cond = dyn_cast<ConstantInt>(II->getArgOperand(0)))
+ return !Cond->isZero();
+
+ return false;
+ }
}
if (isAllocLikeFn(I, TLI)) return true;
}
static bool markAliveBlocks(BasicBlock *BB,
- SmallPtrSet<BasicBlock*, 128> &Reachable) {
+ SmallPtrSetImpl<BasicBlock*> &Reachable) {
SmallVector<BasicBlock*, 128> Worklist;
Worklist.push_back(BB);
// instructions into LLVM unreachable insts. The instruction combining pass
// canonicalizes unreachable insts into stores to null or undef.
for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E;++BBI){
+ // Assumptions that are known to be false are equivalent to unreachable.
+ // Also, if the condition is undefined, then we make the choice most
+ // beneficial to the optimizer, and choose that to also be unreachable.
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BBI))
+ if (II->getIntrinsicID() == Intrinsic::assume) {
+ bool MakeUnreachable = false;
+ if (isa<UndefValue>(II->getArgOperand(0)))
+ MakeUnreachable = true;
+ else if (ConstantInt *Cond =
+ dyn_cast<ConstantInt>(II->getArgOperand(0)))
+ MakeUnreachable = Cond->isZero();
+
+ if (MakeUnreachable) {
+ // Don't insert a call to llvm.trap right before the unreachable.
+ changeToUnreachable(BBI, false);
+ Changed = true;
+ break;
+ }
+ }
+
if (CallInst *CI = dyn_cast<CallInst>(BBI)) {
if (CI->doesNotReturn()) {
// If we found a call to a no-return function, insert an unreachable
return true;
}
+
+void llvm::combineMetadata(Instruction *K, const Instruction *J, ArrayRef<unsigned> KnownIDs) {
+ SmallVector<std::pair<unsigned, MDNode*>, 4> Metadata;
+ K->dropUnknownMetadata(KnownIDs);
+ K->getAllMetadataOtherThanDebugLoc(Metadata);
+ for (unsigned i = 0, n = Metadata.size(); i < n; ++i) {
+ unsigned Kind = Metadata[i].first;
+ MDNode *JMD = J->getMetadata(Kind);
+ MDNode *KMD = Metadata[i].second;
+
+ switch (Kind) {
+ default:
+ K->setMetadata(Kind, nullptr); // Remove unknown metadata
+ break;
+ case LLVMContext::MD_dbg:
+ llvm_unreachable("getAllMetadataOtherThanDebugLoc returned a MD_dbg");
+ case LLVMContext::MD_tbaa:
+ K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD));
+ break;
+ case LLVMContext::MD_alias_scope:
+ case LLVMContext::MD_noalias:
+ K->setMetadata(Kind, MDNode::intersect(JMD, KMD));
+ break;
+ case LLVMContext::MD_range:
+ K->setMetadata(Kind, MDNode::getMostGenericRange(JMD, KMD));
+ break;
+ case LLVMContext::MD_fpmath:
+ K->setMetadata(Kind, MDNode::getMostGenericFPMath(JMD, KMD));
+ break;
+ case LLVMContext::MD_invariant_load:
+ // Only set the !invariant.load if it is present in both instructions.
+ K->setMetadata(Kind, JMD);
+ break;
+ }
+ }
+}