[PATCH] D12277: [X86] Add intrinsic support for clac, stac, lgdt and sgdt

[Reid Kleckner via llvm-commits]

rnk added a comment.

In http://reviews.llvm.org/D12277#231179, @majnemer wrote:

> Are these intrinsics supposed to be compiler barriers? Seems like bad stuff could happen if we speculated or sunk around them.


They have no constraints, which means they are equivalent to a normal external function call. Isn't that enough of a barrier? I think most users (kernels, hypervisors) are fine with LLVM reordering identified object memory accesses across such a barrier.


http://reviews.llvm.org/D12277