make mips64 `Complex` GCC-compatible by folkertdev · Pull Request #162921 · rust-lang/rust

folkertdev · 2026-09-17T19:25:50Z

tracking issue: #154023

This implementation is compatible with GCC and Clang >= 24, see llvm/llvm-project#212109.

This implementation has been validated versus GCC and Clang 24 with abi-cafe.

folkertdev · 2026-09-25T11:39:01Z

r? beetrees

(one of 3 remaining architectures: we're getting there!)

rustbot · 2026-09-25T11:39:06Z

beetrees is currently at their maximum review capacity.
They may take a while to respond.

beetrees

I've verified against GCC's current behaviour.

View changes since this review

beetrees · 2026-09-30T12:20:03Z

+                arg.cast_to_and_pad_i32(Uniform::new(Reg::i64(), size), pad_i32);
+            }
+            Numeric::Float(Float::F128) => {
+                // Complex<f128> is passed in 4 GPRs, but aligned to 16 so may need padding.


Suggested change

// Complex<f128> is passed in 4 GPRs, but aligned to 16 so may need padding.

// Complex<f128> is passed in 4 FPRs, but aligned to 16 so may need padding.

beetrees · 2026-09-30T12:20:46Z

+                arg.cast_to(cast_target.with_attrs(ArgAttribute::InReg.into()));
+            }
+            Numeric::Int(Integer::I64 | Integer::I128, _) => {
+                // Complex<i64> and Complex<i64> are passed as 2 separate arguments, which is what


Suggested change

// Complex<i64> and Complex<i64> are passed as 2 separate arguments, which is what

// Complex<i64> and Complex<i128> are passed as 2 separate arguments, which is what

beetrees · 2026-09-30T12:22:05Z

+            Numeric::Float(Float::F32 | Float::F64) => {
+                // Only pass a Complex<f32>/Complex<f64> in FPRs when two argument slots are free,
+                if curr_offset.bytes() / slot.bytes() + 2 <= NUM_ARG_SLOTS {
+                    // The default `PassMode::Pair` already passes one component per register. Both


Can we use PassMode::Cast rather than relying on PassMode::Pair happening to do the right thing?

beetrees · 2026-09-30T12:22:48Z

+            }
+            Numeric::Int(Integer::I64 | Integer::I128, _) => {
+                // Complex<i64> and Complex<i64> are passed as 2 separate arguments, which is what
+                // the default `PassMode::Pair` already does.


Use PassMode::Cast here too?

beetrees · 2026-09-30T12:40:14Z

+            Numeric::Float(Float::F16) => unreachable!("not supported on mips64"),
+            Numeric::Float(Float::F32 | Float::F64) => {
+                // Only pass a Complex<f32>/Complex<f64> in FPRs when two argument slots are free,
+                if curr_offset.bytes() / slot.bytes() + 2 <= NUM_ARG_SLOTS {


C-variadic arguments are always passed in GPRs, so Complex<f32> needs to be passed in one slot in that case.

If you're wanting to leave C-variadic compatibility till later, leave a FIXME here instead?

beetrees · 2026-09-30T12:43:58Z

Add a test for passing Complex as a C-variadic argument?

Our va_arg can't handle that for most targets at the moment (and VaArgSafe is not implemented for Complex yet). I intend to do another sweep for c-variadic once we have "normal" call support across targets.

rustbot · 2026-09-30T12:44:14Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

rustbot · 2026-09-30T14:07:58Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

folkertdev · 2026-09-30T14:57:38Z

@rustbot ready

beetrees

r=me once FIXME has been added.

View changes since this review

beetrees · 2026-09-30T16:31:44Z

+            Numeric::Float(Float::F16) => unreachable!("not supported on mips64"),
+            Numeric::Float(Float::F32 | Float::F64) => {
+                // Only pass a Complex<f32>/Complex<f64> in FPRs when two argument slots are free,
+                if curr_offset.bytes() / slot.bytes() + 2 <= NUM_ARG_SLOTS {


If you're wanting to leave C-variadic compatibility till later, leave a FIXME here instead?

folkertdev · 2026-09-30T17:40:02Z

fixme added (I assume we can just treat all complex numbers generically for it, but we'll see)

@bors r=beetrees rollup

rust-bors · 2026-09-30T17:40:06Z

📌 Commit dd0f941 has been tentatively approved by beetrees

It will be put into the queue for this repository once PR CI succeeds.

make mips64 `Complex` GCC-compatible tracking issue: rust-lang#154023 This implementation is compatible with GCC and Clang >= 24, see llvm/llvm-project#212109. This implementation has been validated versus GCC and Clang 24 with abi-cafe.

…uwer Rollup of 18 pull requests Successful merges: - #163532 (rustc_codegen_cranelift subtree update) - #163534 (miri subtree update) - #163279 (const and NonZero impl for clamp_magnitude()) - #162900 (Some refactorings around metadata encoding) - #163455 (Don't use the metadata based crate_hash for rustdoc runs) - #159798 (Attribute documentation for cfg_attr) - #162921 (make mips64 `Complex` GCC-compatible) - #163368 (Don't build format string suggestions from `concat!` offsets) - #163375 (Update expect messages in library/std/src/os/unix/net/ following Rust's `expect` guidance) - #163405 (Remove some #[linkage] options) - #163470 (Miscellaneous attr error stuff) - #163489 (expose Rc::is_unique) - #163492 (x86 and x86_64: cleanup some callconv code) - #163496 (cycle handling: mirror old solver) - #163509 (Use more default field values in `Resolver`) - #163519 (Forbid `Reborrow` impls for types with destructors) - #163520 (Cast cleanups) - #163524 (Document `Result` case for the `arena_cache` query modifier)

Rollup of 20 pull requests Successful merges: - #163279 (const and NonZero impl for clamp_magnitude()) - #163081 (Provide more context on "not general enough" error) - #163455 (Don't use the metadata based crate_hash for rustdoc runs) - #159798 (Attribute documentation for cfg_attr) - #162921 (make mips64 `Complex` GCC-compatible) - #163368 (Don't build format string suggestions from `concat!` offsets) - #163375 (Update expect messages in library/std/src/os/unix/net/ following Rust's `expect` guidance) - #163470 (Miscellaneous attr error stuff) - #163489 (expose Rc::is_unique) - #163492 (x86 and x86_64: cleanup some callconv code) - #163496 (cycle handling: mirror old solver) - #163509 (Use more default field values in `Resolver`) - #163519 (Forbid `Reborrow` impls for types with destructors) - #163520 (Cast cleanups) - #163524 (Document `Result` case for the `arena_cache` query modifier) - #163546 (PassWrapper: adapt for new PassPlugin load method) - #163551 (Add libs-nominated triagebot config) - #163559 (Suggest `#[unsafe(no_mangle)]` for entry points in `no_std` binaries) - #163564 (rustc-dev-guide subtree update) - #163568 (remove dead cfg_select! arm)

Rollup merge of #162921 - folkertdev:complex-mips64, r=beetrees make mips64 `Complex` GCC-compatible tracking issue: #154023 This implementation is compatible with GCC and Clang >= 24, see llvm/llvm-project#212109. This implementation has been validated versus GCC and Clang 24 with abi-cafe.

Rollup of 20 pull requests Successful merges: - rust-lang/rust#163279 (const and NonZero impl for clamp_magnitude()) - rust-lang/rust#163081 (Provide more context on "not general enough" error) - rust-lang/rust#163455 (Don't use the metadata based crate_hash for rustdoc runs) - rust-lang/rust#159798 (Attribute documentation for cfg_attr) - rust-lang/rust#162921 (make mips64 `Complex` GCC-compatible) - rust-lang/rust#163368 (Don't build format string suggestions from `concat!` offsets) - rust-lang/rust#163375 (Update expect messages in library/std/src/os/unix/net/ following Rust's `expect` guidance) - rust-lang/rust#163470 (Miscellaneous attr error stuff) - rust-lang/rust#163489 (expose Rc::is_unique) - rust-lang/rust#163492 (x86 and x86_64: cleanup some callconv code) - rust-lang/rust#163496 (cycle handling: mirror old solver) - rust-lang/rust#163509 (Use more default field values in `Resolver`) - rust-lang/rust#163519 (Forbid `Reborrow` impls for types with destructors) - rust-lang/rust#163520 (Cast cleanups) - rust-lang/rust#163524 (Document `Result` case for the `arena_cache` query modifier) - rust-lang/rust#163546 (PassWrapper: adapt for new PassPlugin load method) - rust-lang/rust#163551 (Add libs-nominated triagebot config) - rust-lang/rust#163559 (Suggest `#[unsafe(no_mangle)]` for entry points in `no_std` binaries) - rust-lang/rust#163564 (rustc-dev-guide subtree update) - rust-lang/rust#163568 (remove dead cfg_select! arm)

folkertdev added the F-complex_numbers `#![feature(complex_numbers)]` label Sep 17, 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 Sep 17, 2026

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folkertdev force-pushed the complex-mips64 branch from 8b43135 to 1e27315 Compare September 25, 2026 10:38

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folkertdev force-pushed the complex-mips64 branch from 1e27315 to 74f5bbb Compare September 25, 2026 11:38

rustbot assigned beetrees Sep 25, 2026

folkertdev marked this pull request as ready for review September 25, 2026 11:39

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 Sep 25, 2026

folkertdev mentioned this pull request Sep 25, 2026

C interop: Complex<T> rust-lang/goals#761

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beetrees requested changes Sep 30, 2026

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rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Sep 30, 2026

folkertdev force-pushed the complex-mips64 branch from 74f5bbb to a5b7535 Compare September 30, 2026 14:07

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 Sep 30, 2026

beetrees requested changes Sep 30, 2026

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rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Sep 30, 2026

make mips64 Complex ABI GCC-compatible

dd0f941

folkertdev force-pushed the complex-mips64 branch from a5b7535 to dd0f941 Compare September 30, 2026 17:39

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 Sep 30, 2026

JonathanBrouwer mentioned this pull request Sep 30, 2026

Rollup of 18 pull requests #163566

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jhpratt mentioned this pull request Oct 1, 2026

Rollup of 20 pull requests #163583

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rust-bors Bot merged commit 973d397 into rust-lang:main Oct 1, 2026
13 checks passed

rustbot added this to the 1.101.0 milestone Oct 1, 2026

github-actions Bot mentioned this pull request Oct 3, 2026

Toolchain upgrade to nightly-2026-10-09 flux-rs/flux#1811

Draft

	// Complex<f128> is passed in 4 GPRs, but aligned to 16 so may need padding.
	// Complex<f128> is passed in 4 FPRs, but aligned to 16 so may need padding.

	// Complex<i64> and Complex<i64> are passed as 2 separate arguments, which is what
	// Complex<i64> and Complex<i128> are passed as 2 separate arguments, which is what

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folkertdev commented Sep 17, 2026

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