Port asm tests to cg_gcc

[antoyo]

• Handle CHECK annotations for cg_gcc.
• Port tests/codegen-llvm/asm/.
• Port tests/assembly-llvm/asm/

[harin-ramesh]

https://github.com/rust-lang/rust/tree/main/tests/assembly-llvm/asm
https://github.com/rust-lang/rust/tree/main/tests/codegen-llvm/asm

Just to confirm, are these the tests that need to be ported?

[antoyo]

Yes, it is those tests.

Btw, sorry about not getting back to review your PRs yet, I'm still fairly busy.
I should be able to get back to them in ~2 weeks.

[harin-ramesh]

I noticed that clobbers for registers such as x87 and MMX are currently being dropped.

In src/asm.rs, the existing logic relies on supported_types to determine whether a register is valid for the target. However, these registers are clobber-only, they don’t support any data types. As a result, they get filtered out by the current check. Is this an expected an behavior.

rustc_codegen_gcc/src/asm.rs

Line 221 in daf8bb9

x => x.supported_types(asm_arch, true).iter().any(