valgrind failure `Conditional jump or move depends on uninitialised value(s)`
Labels: triaged, module: sanitizers

### 🐛 Describe the bug

Hi friends! Our internal valgrind build found this report

```
==4329== Warning: noted but unhandled ioctl 0x30000001 with no size/direction hints.
==4329==    This could cause spurious value errors to appear.
==4329==    See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing a proper wrapper.
==4329== Warning: noted but unhandled ioctl 0x27 with no size/direction hints.
==4329==    This could cause spurious value errors to appear.
==4329==    See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing a proper wrapper.
==4329== Warning: noted but unhandled ioctl 0x25 with no size/direction hints.
==4329==    This could cause spurious value errors to appear.
==4329==    See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing a proper wrapper.
==4329== Warning: noted but unhandled ioctl 0x17 with no size/direction hints.
==4329==    This could cause spurious value errors to appear.
==4329==    See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing a proper wrapper.
==4329== Warning: set address range perms: large range [0x200000000, 0x400200000) (noaccess)
==4329== Warning: set address range perms: large range [0x122027000, 0x142026000) (noaccess)
==4329== Conditional jump or move depends on uninitialised value(s)
==4329==    at 0x8AE240D: c10::impl::wrap_kernel_functor_unboxed_<c10::impl::detail::WrapFunctionIntoFunctor_<c10::CompileTimeFunctionPointer<at::Tensor (c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt), &torch::ADInplaceOrView::(anonymous namespace)::slice_Tensor>, at::Tensor, c10::guts::typelist::typelist<c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt> >, at::Tensor (c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt)>::call(c10::OperatorKernel*, c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt) (external/pytorch/c10/util/Optional.h:281)
==4329==    by 0x5167FA88: at::Tensor c10::callUnboxedKernelFunction<at::Tensor, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt>(void*, c10::OperatorKernel*, c10::DispatchKeySet, at::Tensor const&, long&&, c10::optional<c10::SymInt>&&, c10::optional<c10::SymInt>&&, c10::SymInt&&) (external/pytorch/aten/src/ATen/core/boxing/KernelFunction_impl.h:50)
==4329==    by 0x516804B2: at::Tensor c10::Dispatcher::redispatch<at::Tensor, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt>(c10::TypedOperatorHandle<at::Tensor (at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt)> const&, c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt) const (external/pytorch/aten/src/ATen/core/boxing/KernelFunction_impl.h:90)
==4329==    by 0x515C6657: at::_ops::slice_Tensor::redispatch(c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt) (external/pytorch/aten/src/ATen/core/dispatch/Dispatcher.h:453)
==4329==    by 0x833CFBB: at::redispatch::slice_symint(c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt) (bazel-out/k8-fastbuild/bin/external/pytorch/aten/src/ATen/RedispatchFunctions.h:5887)
==4329==    by 0x82DE8F7: c10::impl::wrap_kernel_functor_unboxed_<c10::impl::detail::WrapFunctionIntoFunctor_<c10::CompileTimeFunctionPointer<at::Tensor (c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt), &torch::autograd::VariableType::(anonymous namespace)::slice_Tensor>, at::Tensor, c10::guts::typelist::typelist<c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt> >, at::Tensor (c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt)>::call(c10::OperatorKernel*, c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt) (bazel-out/k8-fastbuild/bin/external/pytorch/torch/csrc/autograd/generated/VariableType_4.cpp:11754)
==4329==    by 0x82E06B2: c10::impl::make_boxed_from_unboxed_functor<c10::impl::detail::WrapFunctionIntoFunctor_<c10::CompileTimeFunctionPointer<at::Tensor (c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt), &torch::autograd::VariableType::(anonymous namespace)::slice_Tensor>, at::Tensor, c10::guts::typelist::typelist<c10::DispatchKeySet, at::Tensor const&, long, c10::optional<c10::SymInt>, c10::optional<c10::SymInt>, c10::SymInt> >, false>::call(c10::OperatorKernel*, c10::OperatorHandle const&, c10::DispatchKeySet, std::vector<c10::IValue, std::allocator<c10::IValue> >*) (external/pytorch/aten/src/ATen/core/boxing/impl/make_boxed_from_unboxed_functor.h:496)
==4329==    by 0x75EFBB8: c10::Dispatcher::callBoxed(c10::OperatorHandle const&, std::vector<c10::IValue, std::allocator<c10::IValue> >*) const (external/pytorch/aten/src/ATen/core/boxing/BoxedKernel_impl.h:41)
==4329==    by 0x6C5708F: torch::jit::InterpreterStateImpl::runImpl(std::vector<c10::IValue, std::allocator<c10::IValue> >&) (external/gcc/x86_64-linux-gnu/include/c++/10.3.0/bits/std_function.h:622)
==4329==    by 0x6C496E9: torch::jit::InterpreterStateImpl::run(std::vector<c10::IValue, std::allocator<c10::IValue> >&) (external/pytorch/torch/csrc/jit/runtime/interpreter.cpp:1009)
==4329==    by 0x6C35273: torch::jit::GraphExecutorImplBase::run(std::vector<c10::IValue, std::allocator<c10::IValue> >&) (external/pytorch/torch/csrc/jit/runtime/graph_executor.cpp:583)
==4329==    by 0x68158D9: torch::jit::Function::operator()(std::vector<c10::IValue, std::allocator<c10::IValue> >, std::unordered_map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, c10::IValue, std::hash<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::equal_to<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, c10::IValue> > > const&) (external/pytorch/aten/src/ATen/core/function.h:62)
==4329==    by 0x6804380: torch::jit::Method::operator()(std::vector<c10::IValue, std::allocator<c10::IValue> >, std::unordered_map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, c10::IValue, std::hash<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::equal_to<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, c10::IValue> > > const&) const (external/pytorch/torch/csrc/jit/api/module.cpp:209)
==4329==    by 0x40C22E3: torch::jit::Module::forward(std::vector<c10::IValue, std::allocator<c10::IValue> >, std::unordered_map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, c10::IValue, std::hash<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::equal_to<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, c10::IValue> > > const&) (external/pytorch/torch/csrc/jit/api/module.h:114)
... <some our code>
```

I binary-searched it to the commit cf3ce329b548e1e8da65542af53b16f27d5dc72a
PR https://github.com/pytorch/pytorch/pull/78947

Unfortunately, I cannot provide a good repro since it's all tied up into our monorepo, but I wanted to have a discussion about it in case it's a real `Conditional jump or move depends on uninitialised value(s)` failure.

### Versions

PyTorch 1.13