disable naked-dead-code-elimination test if no RET mnemonic is available by fneddy · Pull Request #155692 · rust-lang/rust

fneddy · 2026-04-23T13:45:25Z

this test emit x86_64 specific ret asm instruction and should not be compiled on any other arch.

rustbot · 2026-04-23T13:45:30Z

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jieyouxu

Thanks
r? me @bors r+ rollup

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jieyouxu · 2026-04-23T15:33:06Z

Hm actually maybe you want to double-check this,
@bors r-
r? @folkertdev

(double-check intention)

jieyouxu · 2026-04-23T15:39:59Z

Hm why does bors trigger
@bors r-

rustbot · 2026-04-24T07:16:06Z

Some changes occurred in src/tools/compiletest

cc @jieyouxu

compiletest directives have been modified. Please add or update docs for the
new or modified directive in src/doc/rustc-dev-guide/.

rustbot · 2026-04-24T07:29:28Z

The rustc-dev-guide subtree was changed. If this PR only touches the dev guide consider submitting a PR directly to rust-lang/rustc-dev-guide otherwise thank you for updating the dev guide with your changes.

cc @BoxyUwU, @tshepang

fneddy · 2026-04-24T07:30:52Z

@rustbot ready

Add infrastructure to query LLVM backend for specific assembly mnemonics and use it in compiletest to conditionally run tests based on instruction availability. This fixes test failures with naked-dead-code-elimination which requires the `RET` mnemonic. Co-authored-by: Folkert de Vries <flokkievids@gmail.com>

folkertdev · 2026-04-28T09:51:40Z

Nice, thanks!

@bors r+

rust-bors · 2026-04-28T09:51:44Z

📌 Commit 2a8e588 has been approved by folkertdev

It is now in the queue for this repository.

…tion, r=folkertdev disable naked-dead-code-elimination test if no RET mnemonic is available this test emit x86_64 specific ret asm instruction and should not be compiled on any other arch.

Rollup of 5 pull requests Successful merges: - #154325 (Tweak irrefutable let else warning output) - #155273 (Lock stable_crate_ids once in create_crate_num) - #155692 (disable naked-dead-code-elimination test if no RET mnemonic is available) - #155747 (Update documentation for `wasm32-wali-linux-musl` after integrating n…) - #155907 (Handle hkl const closures)

…tion, r=folkertdev disable naked-dead-code-elimination test if no RET mnemonic is available this test emit x86_64 specific ret asm instruction and should not be compiled on any other arch.

…uwer Rollup of 12 pull requests Successful merges: - #151994 (switch to v0 mangling by default on stable) - #154325 (Tweak irrefutable let else warning output) - #155899 (`dlltool`: Set the working directory to workaround `--temp-prefix` bug) - #155273 (Lock stable_crate_ids once in create_crate_num) - #155361 (Document that CFI diverges from Rust wrt. ABI-compatibility rules) - #155692 (disable naked-dead-code-elimination test if no RET mnemonic is available) - #155747 (Update documentation for `wasm32-wali-linux-musl` after integrating n…) - #155768 (compiletest: Overhaul the code for running an incremental test revision) - #155907 (Handle hkl const closures) - #155910 (misc stuff from reading borrowck again :)) - #155913 (Delete the 12 year old fixme) - #155920 (remove review queue triagebot mentions)

…tion, r=folkertdev disable naked-dead-code-elimination test if no RET mnemonic is available this test emit x86_64 specific ret asm instruction and should not be compiled on any other arch.

…uwer Rollup of 14 pull requests Successful merges: - #155850 (Only exclude the #155473 change for 1-byte bool-likes) - #155923 (Subtree sync for rustc_codegen_cranelift) - #151994 (switch to v0 mangling by default on stable) - #154325 (Tweak irrefutable let else warning output) - #155899 (`dlltool`: Set the working directory to workaround `--temp-prefix` bug) - #155273 (Lock stable_crate_ids once in create_crate_num) - #155361 (Document that CFI diverges from Rust wrt. ABI-compatibility rules) - #155692 (disable naked-dead-code-elimination test if no RET mnemonic is available) - #155747 (Update documentation for `wasm32-wali-linux-musl` after integrating n…) - #155768 (compiletest: Overhaul the code for running an incremental test revision) - #155907 (Handle hkl const closures) - #155910 (misc stuff from reading borrowck again :)) - #155913 (Delete the 12 year old fixme) - #155920 (remove review queue triagebot mentions)

…uwer Rollup of 15 pull requests Successful merges: - #155923 (Subtree sync for rustc_codegen_cranelift) - #155930 (Sync from portable simd 2026 04 28) - #155850 (Only exclude the #155473 change for 1-byte bool-likes) - #151994 (switch to v0 mangling by default on stable) - #154325 (Tweak irrefutable let else warning output) - #155273 (Lock stable_crate_ids once in create_crate_num) - #155361 (Document that CFI diverges from Rust wrt. ABI-compatibility rules) - #155692 (disable naked-dead-code-elimination test if no RET mnemonic is available) - #155747 (Update documentation for `wasm32-wali-linux-musl` after integrating n…) - #155768 (compiletest: Overhaul the code for running an incremental test revision) - #155907 (Handle hkl const closures) - #155910 (misc stuff from reading borrowck again :)) - #155913 (Delete the 12 year old fixme) - #155920 (remove review queue triagebot mentions) - #155936 (Rename `SharedContext::emit_dyn_lint*` into `emit_lint*`)

Rollup merge of #155692 - fneddy:fix_naked-dead-code-elimination, r=folkertdev disable naked-dead-code-elimination test if no RET mnemonic is available this test emit x86_64 specific ret asm instruction and should not be compiled on any other arch.

…henyukang use the new `//@ needs-asm-mnemonic: ret` more Since rust-lang#155692 we have this neat new rule, and a couple of tests should be able to use them.

bjorn3 · 2026-04-29T10:25:51Z

+                reason: "skipping test as non-LLVM backend does not support mnemonic queries"
+                    .to_string(),
+            };
+        }


It would have been nicer if this didn't check for LLVM and instead codegen backends by default returned false from the mnemonic query. The CodegenBackend trait could have a has_mnemonic method with a default impl of false.

Fair, the effect is the same but at least that makes it possible for the other backends to implement something, or to e.g. hardcode some mnemonics being available based on the target.

I'll do some refactoring.

Actually, the other codegen backends don't handle any of the other print requests either?

…henyukang use the new `//@ needs-asm-mnemonic: ret` more Since rust-lang#155692 we have this neat new rule, and a couple of tests should be able to use them.

rustbot assigned jieyouxu Apr 23, 2026

rustbot added A-run-make Area: port run-make Makefiles to rmake.rs 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. labels Apr 23, 2026

jieyouxu previously approved these changes Apr 23, 2026

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rust-bors Bot 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 Apr 23, 2026

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fneddy force-pushed the fix_naked-dead-code-elimination branch from e087ea0 to bfe5af9 Compare April 24, 2026 07:16

fneddy changed the title ~~disable naked-dead-code-elimination test on non x86_64~~ disable naked-dead-code-elimination test if no RET mnemonic is available Apr 24, 2026

jieyouxu self-assigned this Apr 24, 2026

fneddy force-pushed the fix_naked-dead-code-elimination branch from bfe5af9 to 1fcdafd Compare April 24, 2026 07:29

rustbot added the A-rustc-dev-guide Area: rustc-dev-guide label Apr 24, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Apr 24, 2026

fneddy force-pushed the fix_naked-dead-code-elimination branch from e3af485 to 6387697 Compare April 27, 2026 13:01

folkertdev reviewed Apr 27, 2026

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Comment thread compiler/rustc_session/src/config/print_request.rs

fneddy force-pushed the fix_naked-dead-code-elimination branch from 6387697 to 2a8e588 Compare April 28, 2026 08:21

rust-bors Bot 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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Apr 28, 2026

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jhpratt mentioned this pull request Apr 28, 2026

Rollup of 5 pull requests #155918

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JonathanBrouwer mentioned this pull request Apr 28, 2026

Rollup of 12 pull requests #155933

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Rollup of 14 pull requests #155937

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JonathanBrouwer mentioned this pull request Apr 28, 2026

Rollup of 15 pull requests #155941

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rust-bors Bot merged commit c6912bf into rust-lang:main Apr 28, 2026
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rustbot added this to the 1.97.0 milestone Apr 28, 2026

folkertdev mentioned this pull request Apr 28, 2026

use the new //@ needs-asm-mnemonic: ret more #155950

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bjorn3 reviewed Apr 29, 2026

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