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Mark condition/carry bit as clobbered in C-SKY inline assembly #136217

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merged 1 commit into from
Feb 13, 2025
Merged

Mark condition/carry bit as clobbered in C-SKY inline assembly #136217

merged 1 commit into from
Feb 13, 2025

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taiki-e
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@taiki-e taiki-e commented Jan 28, 2025

C-SKY's compare and some arithmetic/logical instructions modify condition/carry bit (C) in PSR, but there is currently no way to mark it as clobbered in asm!.

This PR marks it as clobbered except when options(preserves_flags) is used.

Refs:

cc @Dirreke (target maintainer)

r? @Amanieu

@rustbot label +O-csky +A-inline-assembly

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. A-inline-assembly Area: Inline assembly (`asm!(…)`) O-csky Target: glaCSKY above covers over me~ labels Jan 28, 2025
@taiki-e taiki-e mentioned this pull request Jan 28, 2025
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Dirreke commented Jan 29, 2025

Looks great!

@Amanieu
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Amanieu commented Feb 11, 2025

@bors r+

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bors commented Feb 11, 2025

📌 Commit 93465e6 has been approved by Amanieu

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Feb 11, 2025
GuillaumeGomez added a commit to GuillaumeGomez/rust that referenced this pull request Feb 12, 2025
@GuillaumeGomez
Rollup merge of rust-lang#136217 - taiki-e:csky-asm-flags, r=Amanieu
ea64533 
Mark condition/carry bit as clobbered in C-SKY inline assembly

C-SKY's compare and some arithmetic/logical instructions modify condition/carry bit (C) in PSR, but there is currently no way to mark it as clobbered in `asm!`.

This PR marks it as clobbered except when [`options(preserves_flags)`](https://doc.rust-lang.org/reference/inline-assembly.html#r-asm.options.supported-options.preserves_flags) is used.

Refs:
- Section 1.3 "Programming model" and Section 1.3.5 "Condition/carry bit" in CSKY Architecture user_guide:
  https://github.com/c-sky/csky-doc/blob/9f7121f7d40970ba5cc0f15716da033db2bb9d07/CSKY%20Architecture%20user_guide.pdf

  > Under user mode, condition/carry bit (C) is located in the lowest bit of PSR, and it can be
accessed and changed by common user instructions. It is the only data bit that can be visited
under user mode in PSR.

  > Condition or carry bit represents the result after one operation. Condition/carry bit can be
clearly set according to the results of compare instructions or unclearly set as some
high-precision arithmetic or logical instructions. In addition, special instructions such as
DEC[GT,LT,NE] and XTRB[0-3] will influence the value of condition/carry bit.

- Register definition in LLVM:
  https://github.com/llvm/llvm-project/blob/llvmorg-19.1.0/llvm/lib/Target/CSKY/CSKYRegisterInfo.td#L88

cc `@Dirreke` ([target maintainer](https://github.com/rust-lang/rust/blob/aa6f5ab18e67cb815f73e0d53d217bc54b0da924/src/doc/rustc/src/platform-support/csky-unknown-linux-gnuabiv2.md#target-maintainers))

r? `@Amanieu`

`@rustbot` label +O-csky +A-inline-assembly
@GuillaumeGomez GuillaumeGomez mentioned this pull request Feb 12, 2025
Closed
bors added a commit to rust-lang-ci/rust that referenced this pull request Feb 12, 2025
@bors
Auto merge of rust-lang#136930 - GuillaumeGomez:rollup-hjsijmf, r=Gui…
1398103 
…llaumeGomez

Rollup of 9 pull requests

Successful merges:

 - rust-lang#135025 (Cast allocas to default address space)
 - rust-lang#136217 (Mark condition/carry bit as clobbered in C-SKY inline assembly)
 - rust-lang#136699 (std: replace the `FromInner` implementation for addresses with private conversion functions)
 - rust-lang#136758 (tests: `-Copt-level=3` instead of `-O` in assembly tests)
 - rust-lang#136761 (tests: `-Copt-level=3` instead of `-O` in codegen tests)
 - rust-lang#136807 (compiler: internally merge `PtxKernel` into `GpuKernel`)
 - rust-lang#136818 (Implement `read*_exact` for `std:io::repeat`)
 - rust-lang#136831 (Update stdarch)
 - rust-lang#136916 (use cc archiver as default in `cc2ar`)

r? `@ghost`
`@rustbot` modify labels: rollup
jhpratt added a commit to jhpratt/rust that referenced this pull request Feb 13, 2025
@jhpratt
Rollup merge of rust-lang#136217 - taiki-e:csky-asm-flags, r=Amanieu
27465f9 
Mark condition/carry bit as clobbered in C-SKY inline assembly

C-SKY's compare and some arithmetic/logical instructions modify condition/carry bit (C) in PSR, but there is currently no way to mark it as clobbered in `asm!`.

This PR marks it as clobbered except when [`options(preserves_flags)`](https://doc.rust-lang.org/reference/inline-assembly.html#r-asm.options.supported-options.preserves_flags) is used.

Refs:
- Section 1.3 "Programming model" and Section 1.3.5 "Condition/carry bit" in CSKY Architecture user_guide:
  https://github.com/c-sky/csky-doc/blob/9f7121f7d40970ba5cc0f15716da033db2bb9d07/CSKY%20Architecture%20user_guide.pdf

  > Under user mode, condition/carry bit (C) is located in the lowest bit of PSR, and it can be
accessed and changed by common user instructions. It is the only data bit that can be visited
under user mode in PSR.

  > Condition or carry bit represents the result after one operation. Condition/carry bit can be
clearly set according to the results of compare instructions or unclearly set as some
high-precision arithmetic or logical instructions. In addition, special instructions such as
DEC[GT,LT,NE] and XTRB[0-3] will influence the value of condition/carry bit.

- Register definition in LLVM:
  https://github.com/llvm/llvm-project/blob/llvmorg-19.1.0/llvm/lib/Target/CSKY/CSKYRegisterInfo.td#L88

cc ``@Dirreke`` ([target maintainer](https://github.com/rust-lang/rust/blob/aa6f5ab18e67cb815f73e0d53d217bc54b0da924/src/doc/rustc/src/platform-support/csky-unknown-linux-gnuabiv2.md#target-maintainers))

r? ``@Amanieu``

``@rustbot`` label +O-csky +A-inline-assembly
This was referenced Feb 13, 2025
Closed
Merged
bors added a commit to rust-lang-ci/rust that referenced this pull request Feb 13, 2025
@bors
Auto merge of rust-lang#136954 - jhpratt:rollup-koefsot, r=jhpratt
9fcc9cf 
Rollup of 12 pull requests

Successful merges:

 - rust-lang#134090 (Stabilize target_feature_11)
 - rust-lang#135025 (Cast allocas to default address space)
 - rust-lang#135841 (Reject `?Trait` bounds in various places where we unconditionally warned since 1.0)
 - rust-lang#136217 (Mark condition/carry bit as clobbered in C-SKY inline assembly)
 - rust-lang#136699 (std: replace the `FromInner` implementation for addresses with private conversion functions)
 - rust-lang#136806 (Fix cycle when debug-printing opaque types from RPITIT)
 - rust-lang#136807 (compiler: internally merge `PtxKernel` into `GpuKernel`)
 - rust-lang#136818 (Implement `read*_exact` for `std:io::repeat`)
 - rust-lang#136927 (Correctly escape hashtags when running `invalid_rust_codeblocks` lint)
 - rust-lang#136937 (Update books)
 - rust-lang#136945 (Add diagnostic item for `std::io::BufRead`)
 - rust-lang#136947 (Reinstate nnethercote in the review rotation.)

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 0de2341 into rust-lang:master Feb 13, 2025
6 checks passed
@rustbot rustbot added this to the 1.86.0 milestone Feb 13, 2025
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request Feb 13, 2025
@rust-timer
Unrolled build for rust-lang#136217
f8c17ac 
Rollup merge of rust-lang#136217 - taiki-e:csky-asm-flags, r=Amanieu

Mark condition/carry bit as clobbered in C-SKY inline assembly

C-SKY's compare and some arithmetic/logical instructions modify condition/carry bit (C) in PSR, but there is currently no way to mark it as clobbered in `asm!`.

This PR marks it as clobbered except when [`options(preserves_flags)`](https://doc.rust-lang.org/reference/inline-assembly.html#r-asm.options.supported-options.preserves_flags) is used.

Refs:
- Section 1.3 "Programming model" and Section 1.3.5 "Condition/carry bit" in CSKY Architecture user_guide:
  https://github.com/c-sky/csky-doc/blob/9f7121f7d40970ba5cc0f15716da033db2bb9d07/CSKY%20Architecture%20user_guide.pdf

  > Under user mode, condition/carry bit (C) is located in the lowest bit of PSR, and it can be
accessed and changed by common user instructions. It is the only data bit that can be visited
under user mode in PSR.

  > Condition or carry bit represents the result after one operation. Condition/carry bit can be
clearly set according to the results of compare instructions or unclearly set as some
high-precision arithmetic or logical instructions. In addition, special instructions such as
DEC[GT,LT,NE] and XTRB[0-3] will influence the value of condition/carry bit.

- Register definition in LLVM:
  https://github.com/llvm/llvm-project/blob/llvmorg-19.1.0/llvm/lib/Target/CSKY/CSKYRegisterInfo.td#L88

cc ```@Dirreke``` ([target maintainer](https://github.com/rust-lang/rust/blob/aa6f5ab18e67cb815f73e0d53d217bc54b0da924/src/doc/rustc/src/platform-support/csky-unknown-linux-gnuabiv2.md#target-maintainers))

r? ```@Amanieu```

```@rustbot``` label +O-csky +A-inline-assembly
@taiki-e taiki-e deleted the csky-asm-flags branch February 13, 2025 12:44
bjorn3 pushed a commit to bjorn3/rust that referenced this pull request Feb 15, 2025
@bors
Auto merge of rust-lang#136954 - jhpratt:rollup-koefsot, r=jhpratt
f9116db 
Rollup of 12 pull requests

Successful merges:

 - rust-lang#134090 (Stabilize target_feature_11)
 - rust-lang#135025 (Cast allocas to default address space)
 - rust-lang#135841 (Reject `?Trait` bounds in various places where we unconditionally warned since 1.0)
 - rust-lang#136217 (Mark condition/carry bit as clobbered in C-SKY inline assembly)
 - rust-lang#136699 (std: replace the `FromInner` implementation for addresses with private conversion functions)
 - rust-lang#136806 (Fix cycle when debug-printing opaque types from RPITIT)
 - rust-lang#136807 (compiler: internally merge `PtxKernel` into `GpuKernel`)
 - rust-lang#136818 (Implement `read*_exact` for `std:io::repeat`)
 - rust-lang#136927 (Correctly escape hashtags when running `invalid_rust_codeblocks` lint)
 - rust-lang#136937 (Update books)
 - rust-lang#136945 (Add diagnostic item for `std::io::BufRead`)
 - rust-lang#136947 (Reinstate nnethercote in the review rotation.)

r? `@ghost`
`@rustbot` modify labels: rollup
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