[llvm] [AMDGPU] New GFX11+ aliases v_dot4_i32_i8 and v_dot8_i32_i4 (PR #118997)

[Jay Foad via llvm-commits]

jayfoad wrote:

> wouldn't it make sense to set `neg_lo:[1,1,0]` by default for these opcodes? Then they would behave like gfx9/10 opcodes with the same names.

Maybe, if the goal was to provide backwards compatibility of handwritten assembly code. But that's really not a goal of the LLVM assembler. The _only_ reason for implementing these aliases is for compatibility with the proprietary assembler.

https://github.com/llvm/llvm-project/pull/118997