rustc_target: Use rustc_abi instead of cfg_abi to detect powerpcspe by taiki-e · Pull Request #157140 · rust-lang/rust

taiki-e · 2026-05-30T05:05:50Z

When self-reviewing #157137, I recalled a previous my comment (#153876 (comment)) about a case where cfg_abi is referred but rustc_abi should be referred.

There is another powerpc code that refers to abi field, but it should be changed to refer to the target feature.

tests/codegen-llvm/asm/powerpc-clobbers.rs contains a test to check whether this detection is working properly:

rust/tests/codegen-llvm/asm/powerpc-clobbers.rs

Line 123 in 6368fd5

// powerpcspe: asm sideeffect "nop", "={r0},={r3},={r4},={r5},={r6},={r7},={r8},={r9},={r10},={r11},={r12},~{cr0},~{cr1},~{cr5},~{cr6},~{cr7},~{ctr},~{lr},~{xer},~{spe_acc}"()

r? @RalfJung

@rustbot label +O-PowerPC +A-target-feature

rustbot · 2026-05-30T05:05:55Z

RalfJung is not on the review rotation at the moment.
They may take a while to respond.

RalfJung · 2026-05-30T08:38:40Z


+pub(crate) fn is_spe(target_features: &FxIndexSet<Symbol>) -> bool {
+ target_features.contains(&sym::spe)
+}


No, we can't do this. Target features are not guaranteed to be consistent across the crate graph. Also we shouldn't parse the target feature like this. Instead, we have the target unambiguously indicate the ABI and then we force the target features to match.
I am working on extending #157085 with SPE support.

Here's a patch that extends our existing ABI tracking to also cover SPE:
751237abda7

taiki-e · 2026-06-04T16:10:50Z

Updated to refer rustc_abi.

RalfJung · 2026-06-04T16:21:11Z

@bors r+ rollup

Nice, removing more cfg_abi usage in the compiler is always a good sign.

rust-bors · 2026-06-04T16:21:15Z

📌 Commit d4e6f26 has been approved by RalfJung

It is now in the queue for this repository.

…uwer Rollup of 8 pull requests Successful merges: - #156281 (Emit nofree attribute) - #157305 (Eagerly decide whether relaxed bounds are allowed or not) - #148713 (rustc_borrowck: fix async closure error note to report AsyncFn rather than Fn) - #156266 (Don't ICE in has_self_borrows when coroutine captures-by-ref ty is still inferred) - #156417 (Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait is not implemented) - #156956 (Support generic params in `Lift_Generic`) - #157140 ( rustc_target: Use rustc_abi instead of cfg_abi to detect powerpcspe ) - #157423 (Refactor/expand rustc_attr_parsing docs)

@RalfJung

Rollup merge of #157140 - taiki-e:powerpcspe-asm, r=RalfJung rustc_target: Use rustc_abi instead of cfg_abi to detect powerpcspe When self-reviewing #157137, I recalled a previous my comment (#153876 (comment)) about a case where cfg_abi is referred but rustc_abi should be referred. > There is another powerpc code that [refers to `abi` field](https://github.com/rust-lang/rust/blob/bfc05d6b072585dfd0c792ec1b8728c08a3511fe/compiler/rustc_target/src/asm/powerpc.rs#L125), but it should be changed to refer to the target feature. `tests/codegen-llvm/asm/powerpc-clobbers.rs` contains a test to check whether this detection is working properly: https://github.com/rust-lang/rust/blob/6368fd52cb9f230dfb156097625993e7a8891800/tests/codegen-llvm/asm/powerpc-clobbers.rs#L123 r? @RalfJung @rustbot label +O-PowerPC +A-target-feature

JonathanBrouwer · 2026-06-05T12:07:30Z

@rust-timer build 5fb2ec4

rust-timer · 2026-06-05T13:32:42Z

Finished benchmarking commit (5fb2ec4): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.1%	[0.1%, 0.1%]	1
Improvements ✅ (primary)	-0.7%	[-0.7%, -0.7%]	1
Improvements ✅ (secondary)	-0.1%	[-0.4%, -0.0%]	4
All ❌✅ (primary)	-0.7%	[-0.7%, -0.7%]	1

Max RSS (memory usage)

Results (primary -1.3%, secondary 1.8%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	4.5%	[2.9%, 6.2%]	2
Regressions ❌ (secondary)	5.7%	[5.7%, 5.7%]	1
Improvements ✅ (primary)	-5.2%	[-6.0%, -4.1%]	3
Improvements ✅ (secondary)	-2.2%	[-2.2%, -2.2%]	1
All ❌✅ (primary)	-1.3%	[-6.0%, 6.2%]	5

Cycles

Results (primary -3.6%, secondary -3.3%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	3.6%	[3.0%, 4.2%]	2
Improvements ✅ (primary)	-3.6%	[-7.6%, -1.4%]	118
Improvements ✅ (secondary)	-3.5%	[-8.1%, -1.6%]	101
All ❌✅ (primary)	-3.6%	[-7.6%, -1.4%]	118

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 512.944s -> 512.514s (-0.08%)
Artifact size: 398.65 MiB -> 398.64 MiB (-0.00%)

JonathanBrouwer · 2026-06-05T13:46:25Z

@rustbot label: +perf-regression-triaged
Noise

…uwer Rollup of 8 pull requests Successful merges: - rust-lang/rust#156281 (Emit nofree attribute) - rust-lang/rust#157305 (Eagerly decide whether relaxed bounds are allowed or not) - rust-lang/rust#148713 (rustc_borrowck: fix async closure error note to report AsyncFn rather than Fn) - rust-lang/rust#156266 (Don't ICE in has_self_borrows when coroutine captures-by-ref ty is still inferred) - rust-lang/rust#156417 (Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait is not implemented) - rust-lang/rust#156956 (Support generic params in `Lift_Generic`) - rust-lang/rust#157140 ( rustc_target: Use rustc_abi instead of cfg_abi to detect powerpcspe ) - rust-lang/rust#157423 (Refactor/expand rustc_attr_parsing docs)

…nathanBrouwer Rollup of 8 pull requests Successful merges: - rust-lang#156281 (Emit nofree attribute) - rust-lang#157305 (Eagerly decide whether relaxed bounds are allowed or not) - rust-lang#148713 (rustc_borrowck: fix async closure error note to report AsyncFn rather than Fn) - rust-lang#156266 (Don't ICE in has_self_borrows when coroutine captures-by-ref ty is still inferred) - rust-lang#156417 (Fix an ICE in the vtable iteration for a trait reference in const eval when a supertrait is not implemented) - rust-lang#156956 (Support generic params in `Lift_Generic`) - rust-lang#157140 ( rustc_target: Use rustc_abi instead of cfg_abi to detect powerpcspe ) - rust-lang#157423 (Refactor/expand rustc_attr_parsing docs)

rustbot assigned RalfJung May 30, 2026

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels May 30, 2026

rustbot added A-target-feature Area: Enabling/disabling target features like AVX, Neon, etc. O-PowerPC Target: PowerPC processors labels May 30, 2026

RalfJung reviewed May 30, 2026
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RalfJung mentioned this pull request May 30, 2026
powerpc: warn against incorrect values for ABI-relevant target features #157085
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rustc_target: Use rustc_abi instead of cfg_abi to detect powerpcspe
d4e6f26

taiki-e force-pushed the powerpcspe-asm branch from 6879f9a to d4e6f26Compare June 4, 2026 14:53

taiki-e changed the title ~~rustc_target: Use target_feature instead of cfg_abi to detect powerpcspe~~ rustc_target: Use rustc_abi instead of cfg_abi to detect powerpcspe Jun 4, 2026

taiki-e marked this pull request as ready for review June 4, 2026 16:10

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 Jun 4, 2026

rust-borsBot 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 Jun 4, 2026

JonathanBrouwer mentioned this pull request Jun 4, 2026
Rollup of 8 pull requests #157440
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rust-borsBot merged commit 7ff0bb8 into rust-lang:mainJun 4, 2026
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rustbot added this to the 1.98.0 milestone Jun 4, 2026

taiki-e deleted the powerpcspe-asm branch June 5, 2026 00:51

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rustbot added the perf-regression Performance regression. label Jun 5, 2026

rustbot added the perf-regression-triaged The performance regression has been triaged. label Jun 5, 2026

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rustc_target: Use rustc_abi instead of cfg_abi to detect powerpcspe - #157140

rustc_target: Use rustc_abi instead of cfg_abi to detect powerpcspe #157140
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Overall result: ❌✅ regressions and improvements - please read:

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