[lld] [RISCV] Disable gp relaxation if part of object unreachable (PR #72655)

[Fangrui Song via llvm-commits]

MaskRay wrote:

That answer doesn't resolve my question. This test uses a very small alignment and cannot guarantee `%hi(Var0) == %hi(Var0+4)`. As such, it cannot prove that this is an issue that should be done at the linker side rather than at the compiler side (possibly disable this `%hi`-sharing feature). It seems that we need some discussions on the right semantics possibly in riscv-elf-psabi-doc. A clarification on riscv-asm-manual may be useful as well to help hand-written assembly.

https://github.com/llvm/llvm-project/pull/72655