[llvm] [AMDGPU] Add lit() asm operand modifier for SP3 compatibility. (PR #68839)

[Jay Foad via llvm-commits]

jayfoad wrote:

> This does not force literal encoding for an inline immediate, but neither does SP3. The syntax is dummy for compatibility only.

Thanks. This sounds OK to me. Really we should go one better than SP3 and force literal encoding, but I guess that is hard to implement.

Do you think the disassembler should emit lit(), either for all literal operands or at least for ones that could have been encoded as inlines?

Does your implementation accept `lit(abs(123.0))`? Does SP3 accept that?

https://github.com/llvm/llvm-project/pull/68839