const-prop checks statics for whether they contain relocations, and if they do, it refuses to read from them. It is not clear why that happens.

As discussed in #70241 (comment), it turns out that const-prop will sometimes permit reading from mutable global allocations. That could be a soundness issue in case those allocations are actually mutated at run-time; const-prop would then be propagating non-constant data.

Currently it is not entirely clear what those mutable allocations are that const-prop is reading from, all we have is an ICE because an unexpected error ("const-prop does not support reading from mutable global allocation") arose during validation. It is also unclear (to me, at least) why const-prop is doing validation at all.

Cc @oli-obk @wesleywiser