[llvm] [AMDGPU] Emit b32 movs if (a)v_mov_b64_pseudo dest vgprs are misaligned (PR #160547)

[Jay Foad via llvm-commits]

jayfoad wrote:

> > As far as I can tell there is no bug here, and if there was a bug it would be in whatever created V_MOV_B64_PSEUDO with unaligned VGPRs in the first place.
> 
> V_MOV_B64_PSEUDO should support unaligned registers, any change should be to relax the restriction

No objection to that. But that's not what this patch currently does.

https://github.com/llvm/llvm-project/pull/160547