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Rollup merge of rust-lang#131258 - taiki-e:s390x-stabilize-asm, r=Amanieu Stabilize s390x inline assembly This stabilizes inline assembly for s390x (SystemZ). Corresponding reference PR: rust-lang/reference#1643 --- From the requirements of stabilization mentioned in rust-lang#93335 > Each architecture needs to be reviewed before stabilization: > - It must have clobber_abi. Done in rust-lang#130630. > - It must be possible to clobber every register that is normally clobbered by a function call. Done in the PR that added support for clobber_abi. > - Generally review that the exposed register classes make sense. The followings can be used as input/output: - `reg` (`r[0-10]`, `r[12-14]`): General-purpose register - `reg_addr` (`r[1-10]`, `r[12-14]`): General-purpose register except `r0` which is evaluated as zero in an address context This class is needed because `r0`, which may be allocated when using the `reg` class, cannot be used as a register in certain contexts. This is identical to the `a` constraint in LLVM and GCC. See rust-lang#119431 for details. - `freg` (`f[0-15]`): Floating-point register The followings are clobber-only: - `vreg` (`v[0-31]`): Vector register Technically `vreg` should be able to accept `#[repr(simd)]` types as input/output if the unstable `vector` target feature added is enabled, but `core::arch` has no s390x vector type and both `#[repr(simd)]` and `core::simd` are unstable. Everything related is unstable, so the fact that this is currently a clobber-only should not be considered a stabilization blocker. (rust-lang#130869 tracks unstable stuff here) - `areg` (`a[2-15]`): Access register All of the above register classes except `reg_addr` are needed for `clobber_abi`. The followings cannot be used as operands for inline asm (see also [getReservedRegs](https://github.com/llvm/llvm-project/blob/llvmorg-19.1.0/llvm/lib/Target/SystemZ/SystemZRegisterInfo.cpp#L258-L282) and [SystemZELFRegisters](https://github.com/llvm/llvm-project/blob/llvmorg-19.1.0/llvm/lib/Target/SystemZ/SystemZRegisterInfo.h#L107-L128) in LLVM): - `r11`: frame pointer - `r15`: stack pointer - `a0`, `a1`: Reserved for system use - `c[0-15]` (control register) Reserved by the kernel Although not listed in the above requirements, `preserves_flags` is implemented in rust-lang#111331. --- cc ``@uweigand`` r? ``@Amanieu`` ``@rustbot`` label +O-SystemZ +A-inline-assembly
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