LLVM 20 produces different assembly for rust/tests/assembly/riscv-soft-abi-with-float-features.rs

[krasimirgg]

After https://github.com/rust-lang/rust/pull/131807, we're seeing some test failures in our experimental rust + LLVM-at-HEAD build bot:

• https://buildkite.com/llvm-project/rust-llvm-integrate-prototype/builds/32097#0192c31f-15a1-47c2-a4c2-a946d7b089a2/951-952

It seems that here the new assembly is just lw a0, 0(a0); not sure if that's OK.

https://github.com/rust-lang/rust/blob/97ae1df8aa9fa6dfd29dced18b232d25208c4111/tests/assembly/riscv-soft-abi-with-float-features.rs#L34

[krasimirgg]

@rustbot label: A-LLVM

[jieyouxu]

cc @beetrees @workingjubilee as you may know more about the intended behavior