• Support const operands.
  • For inline asm (https://github.com/bjorn3/rustc_codegen_cranelift/pull/1350)
  • For global asm (https://github.com/bjorn3/rustc_codegen_cranelift/pull/1351)
• Support sym operands.
  • For inline asm (https://github.com/bjorn3/rustc_codegen_cranelift/pull/1350)
  • For global asm (https://github.com/bjorn3/rustc_codegen_cranelift/pull/1351, but doesn't work when the function is made private to the codegen unit)
  • Missing symbol mangling (_ prefix for Mach-O) (Add leading underscore to asm symbols on Mach-O #1630)
• Support asm goto (Stabilize asm_goto feature gate rust#133870 will stabilize it for cg_llvm)
• Support register classes. This will require writing a mini register allocator to solve all register constraints. (Improve inline asm support #1206)
• Optimize
  • Overlap input and output stack slots. (Improve inline asm support #1206)
  • Skip saving caller saved registers. (Improve inline asm support #1206)
• Support more architectures
  • aarch64 (https://github.com/bjorn3/rustc_codegen_cranelift/pull/1396)
  • riscv64 (Add riscv64 linux support #1398)
  • ...
• Support inline asm on macOS (https://github.com/bjorn3/rustc_codegen_cranelift/pull/1397)
• Support inline asm on Windows (Support and stabilize inline asm on all platforms #1403)
• Avoid the object file linking hack. It doesn't work on macOS and Windows but is currently necessary as incr comp expects each codegen unit to provide a single object file instead of allowing an extra object file for the compiled assembly. (Refactorings for enabling parallel compilation (part 1) #1264)
• Use cgu name instead of function name as base for assembly stub names. The same function name may be used in multiple cgus when using #[inline]. (1222192)
• Run inline asm tests from the rustc test suite (https://github.com/bjorn3/rustc_codegen_cranelift/pull/1397)
• Enable support by default (Support and stabilize inline asm on all platforms #1403)

Tracking issue for stabilizing asm!(): rust-lang/rust#72016 Has been stabilized.