As reported in https://bugs.freebsd.org/240765, compiling the commoncpp port with clang 9.0.0 results in an assertion:

Assertion failed: (A->getParent() == B->getParent() && "Instructions must be in the same basic block!"), function dominates, file /lib/Analysis/OrderedBasicBlock.cpp, line 68.

#0  thr_kill () at thr_kill.S:3
#1  0x0000000804812934 in __raise (s=6) at /usr/src/lib/libc/gen/raise.c:52
#2  0x0000000804785d99 in abort () at /usr/src/lib/libc/stdlib/abort.c:67
#3  0x00000008048025c1 in __assert (func=<optimized out>, file=<optimized out>, line=<optimized out>, failedexpr=<optimized out>) at /usr/src/lib/libc/gen/assert.c:51
#4  0x0000000001d6e6d6 in llvm::OrderedBasicBlock::dominates(llvm::Instruction const*, llvm::Instruction const*) ()
#5  0x0000000002649878 in eliminateDeadStores(llvm::BasicBlock&, llvm::AAResults*, llvm::MemoryDependenceResults*, llvm::DominatorTree*, llvm::TargetLibraryInfo const*) ()
#6  0x0000000002650445 in (anonymous namespace)::DSELegacyPass::runOnFunction(llvm::Function&) ()
#7  0x000000000231b673 in llvm::FPPassManager::runOnFunction(llvm::Function&) ()
#8  0x00000000020e1b95 in (anonymous namespace)::CGPassManager::runOnModule(llvm::Module&) ()
#9  0x000000000231be62 in llvm::legacy::PassManagerImpl::run(llvm::Module&) ()
#10 0x0000000002a643d1 in clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::DataLayout const&, llvm::Module*, clang::BackendAction, std::__1::unique_ptr<llvm::raw_pwrite_stream, std::__1::default_delete<llvm::raw_pwrite_stream> >) ()
#11 0x00000000030e6fed in clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) ()
#12 0x00000000038117e3 in clang::ParseAST(clang::Sema&, bool, bool) ()
#13 0x000000000304ab0a in clang::FrontendAction::Execute() ()
#14 0x0000000002fc85c1 in clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) ()
#15 0x00000000030e0dde in clang::ExecuteCompilerInvocation(clang::CompilerInstance*) ()
#16 0x000000000145c43d in cc1_main(llvm::ArrayRef<char const*>, char const*, void*) ()
#17 0x000000000145a0db in main ()

This regressed with https://reviews.llvm.org/rL357222 (Recommit "[DSE] Preserve basic block ordering using OrderedBasicBlock"), which was a recommit of https://reviews.llvm.org/rL357208 for bug 38829.

Minimized test case:

// clang -cc1 -triple x86_64-- -S -O1 -fexceptions in6addr-min.cpp
struct a {
  int b[6];
};
extern "C" void *memcpy(void *, void *, long);
struct c {
  a *d;
  int e;
  c();
};
c::c() : e() {
  d = new a;
  memcpy(&d, 0, sizeof(a));
}