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Rollup merge of #111331 - taiki-e:s390x-asm-cc, r=Amanieu

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Mark s390x condition code register as clobbered in inline assembly

Various s390x instructions (arithmetic operations, logical operations, comparisons, etc. see also "Condition Codes" section in [z/Architecture Reference Summary](https://www.ibm.com/support/pages/zarchitecture-reference-summary)) modify condition code register `cc`, but AFAIK there is currently no way to mark it as clobbered in `asm!`.

`cc` register definition in LLVM:
https://github.com/llvm/llvm-project/blob/main/llvm/lib/Target/SystemZ/SystemZRegisterInfo.td#L320

This PR also updates asm_experimental_arch docs in the unstable-book to mention s390x registers.

cc `@uweigand`

r? `@Amanieu`
This commit is contained in:
Yuki Okushi 2023-05-08 19:41:50 +09:00 committed by GitHub
commit c122ac3e69
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2 changed files with 14 additions and 3 deletions
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4
compiler/rustc_codegen_llvm/src/asm.rs
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@ -238,7 +238,9 @@ impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
InlineAsmArch::Hexagon => {}
InlineAsmArch::LoongArch64 => {}
InlineAsmArch::Mips | InlineAsmArch::Mips64 => {}
InlineAsmArch::S390x => {}
InlineAsmArch::S390x => {
constraints.push("~{cc}".to_string());
}
InlineAsmArch::SpirV => {}
InlineAsmArch::Wasm32 | InlineAsmArch::Wasm64 => {}
InlineAsmArch::Bpf => {}

13
src/doc/unstable-book/src/language-features/asm-experimental-arch.md
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@ -18,6 +18,7 @@ This feature tracks `asm!` and `global_asm!` support for the following architect
- MSP430
- M68k
- LoongArch
- s390x
## Register classes
@ -48,6 +49,8 @@ This feature tracks `asm!` and `global_asm!` support for the following architect
| M68k | `reg_addr` | `a[0-3]` | `a` |
| LoongArch | `reg` | `$r1`, `$r[4-20]`, `$r[23,30]` | `r` |
| LoongArch | `freg` | `$f[0-31]` | `f` |
| s390x | `reg` | `r[0-10]`, `r[12-14]` | `r` |
| s390x | `freg` | `f[0-15]` | `f` |
> **Notes**:
> - NVPTX doesn't have a fixed register set, so named registers are not supported.
@ -81,6 +84,8 @@ This feature tracks `asm!` and `global_asm!` support for the following architect
| M68k | `reg_data` | None | `i8`, `i16`, `i32` |
| LoongArch64 | `reg` | None | `i8`, `i16`, `i32`, `i64`, `f32`, `f64` |
| LoongArch64 | `freg` | None | `f32`, `f64` |
| s390x | `reg` | None | `i8`, `i16`, `i32`, `i64` |
| s390x | `freg` | None | `f32`, `f64` |
## Register aliases
@ -115,8 +120,8 @@ This feature tracks `asm!` and `global_asm!` support for the following architect
| Architecture | Unsupported register | Reason |
| ------------ | --------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| All | `sp` | The stack pointer must be restored to its original value at the end of an asm code block. |
| All | `fr` (Hexagon), `$fp` (MIPS), `Y` (AVR), `r4` (MSP430), `a6` (M68k), `$fp` (LoongArch) | The frame pointer cannot be used as an input or output. |
| All | `sp`, `r15` (s390x) | The stack pointer must be restored to its original value at the end of an asm code block. |
| All | `fr` (Hexagon), `$fp` (MIPS), `Y` (AVR), `r4` (MSP430), `a6` (M68k), `$fp` (LoongArch), `r11` (s390x) | The frame pointer cannot be used as an input or output. |
| All | `r19` (Hexagon) | This is used internally by LLVM as a "base pointer" for functions with complex stack frames. |
| MIPS | `$0` or `$zero` | This is a constant zero register which can't be modified. |
| MIPS | `$1` or `$at` | Reserved for assembler. |
@ -147,6 +152,8 @@ This feature tracks `asm!` and `global_asm!` support for the following architect
| PowerPC | `freg` | None | `0` | None |
| LoongArch | `reg` | None | `$r2` | None |
| LoongArch | `freg` | None | `$f0` | None |
| s390x | `reg` | None | `%r0` | None |
| s390x | `freg` | None | `%f0` | None |
# Flags covered by `preserves_flags`
@ -157,3 +164,5 @@ These flags registers must be restored upon exiting the asm block if the `preser
- The status register `r2`.
- M68k
- The condition code register `ccr`.
- s390x
- The condition code register `cc`.