This tracks support for additional registers in architectures where inline assembly is already stable.
The feature gate for the issue is #![feature(asm_experimental_reg)].

About tracking issues

Tracking issues are used to record the overall progress of implementation.
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.
Discussion comments will get marked as off-topic or deleted.
Repeated discussions on the tracking issue may lead to the tracking issue getting locked.

Steps

• Implementation (see implementation history below)
• Stabilization PR (see instructions on rustc-dev-guide)

Unresolved Questions

Implementation history

• s390x vreg input/output
  • Implementation Support input/output in vector registers of s390x inline assembly (under asm_experimental_reg feature) #131664
• RISC-V reg_pair
  • Implementation Support GPR pair in RISC-V inline assembly #150973
• x86 {xyz}mm_reg {i,u}128 input/output
  • Implementation x86: support passing u128/i128 to inline assembly #151059

Other candidates:

• GPR pair on Arm and s390x
• AArch64 SVE types
• RISC-V RVV types

@rustbot label +A-inline-assembly +O-SystemZ +O-riscv +O-x86_32 +O-x86_64