[llvm] r254917 - Link declaration lazily.

[Rafael Espíndola via llvm-commits]

> This breaks Halide (halide-lang.org), which links together a bunch of .ll
> files to form its runtime library, and relies on declarations being
> preserved by that link step (in particular, it has declarations of various
> intrinsics that it wants to look up by name later). Is there any way to turn
> this off, to get back the "preserve all globals" behavior we used to have
> here?

Note that the behaviour was not "preserve all globals". We were
already lazy linking declarations that can be dropped, like
linkonce_odr and internal.

Expecting that a declaration will be copied but a linkonce_odr will
not is pretty broken.

How do I reproduce this?

Cheers,
Rafael