Run cg_gcc tests with the correct compiler by Kobzol · Pull Request #163533 · rust-lang/rust

Kobzol · 2026-09-30T10:11:59Z

Seems like we have been running the tests with the stage 0 compiler all along :surprised: The tests crash with:

[BUILD] mini_core
[BUILD] example
[AOT] mini_core_hello_world
warning: the feature `never_type` has been stable since 1.101.0-dev and no longer requires an attribute to enable
 --> example/mini_core_hello_world.rs:4:44
  |
4 |     no_core, unboxed_closures, lang_items, never_type, linkage,
  |                                            ^^^^^^^^^^
  |
  = note: `#[warn(stable_features)]` on by default


thread 'rustc' (1671953) panicked at compiler/rustc_codegen_ssa/src/mir/rvalue.rs:1114:5:
assertion `left == right` failed
  left: __int8_t *  __attribute__((aligned(8)))
 right: void *
stack backtrace:
   0: __rustc::rust_begin_unwind
             at /rustc/cbae9b4cae2b108f6a3d18cfe6075714bb739463/library/std/src/panicking.rs:679:5
   1: core::panicking::panic_fmt
             at /rustc/cbae9b4cae2b108f6a3d18cfe6075714bb739463/library/core/src/panicking.rs:80:14
   2: core::panicking::assert_failed_inner
             at /rustc/cbae9b4cae2b108f6a3d18cfe6075714bb739463/library/core/src/panicking.rs:452:17
   3: core::panicking::assert_failed::<gccjit::types::Type, gccjit::types::Type>
             at /rustc/cbae9b4cae2b108f6a3d18cfe6075714bb739463/library/core/src/panicking.rs:407:5
   4: transmute_scalar<rustc_codegen_gcc::builder::Builder>
   5: codegen_transmute_operand<rustc_codegen_gcc::builder::Builder>
             at /home/bjorn/rust/compiler/rustc_codegen_ssa/src/mir/rvalue.rs:419:21
   6: codegen_rvalue_operand<rustc_codegen_gcc::builder::Builder>
             at /home/bjorn/rust/compiler/rustc_codegen_ssa/src/mir/rvalue.rs:625:30
   7: codegen_statement<rustc_codegen_gcc::builder::Builder>
             at /home/bjorn/rust/compiler/rustc_codegen_ssa/src/mir/statement.rs:37:52

I'll need help with resolving that from the cg_gcc side (CC @antoyo).

Fixes: #163527

antoyo · 2026-09-30T13:16:08Z

Debug assertions are expected to be disabled for cg_gcc. This is a known issue.

Kobzol · 2026-09-30T13:43:38Z

So I should change bootstrap to compile cg_gcc without debug assertions, and that's it?

antoyo · 2026-09-30T13:58:55Z

So I should change bootstrap to compile cg_gcc without debug assertions, and that's it?

I'm not sure if it is cg_gcc or rustc that needs to be compiled without debug assertion.
In case that helps, my bootstrap.toml contains:

[rust]
codegen-backends = ["gcc"]
deny-warnings = false
debug-assertions = false
debug-assertions-std = false
lto = "off"

bjorn3 · 2026-09-30T14:00:44Z

cg_ssa needs to be compiled without debug assertions as the debug assertion that fails is in cg_ssa.

Kobzol · 2026-09-30T14:12:13Z

Hmm, that means that we'd have to run all cg_gcc tests without debug assertions. Well, doable, I guess, but annoying for local experiments.

Kobzol · 2026-10-02T10:21:26Z

Hmm, I realized that we don't actually run these tests in CI, unless I missed something. We only test UI tests and library tests at the moment (which is also why we didn't catch this earlier).

So I guess that we can already merge this as-is, it just won't work with debug assertions enabled. I at least added a warning.

rustbot · 2026-10-02T10:21:30Z

rustc_codegen_gcc is developed in its own repository. If possible, consider making this change to rust-lang/rustc_codegen_gcc instead.

cc @antoyo, @GuillaumeGomez

rustbot · 2026-10-02T10:21:33Z

r? @Mark-Simulacrum

rustbot has assigned @Mark-Simulacrum.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

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bootstrap expanded to 6 candidates
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Kobzol · 2026-10-02T10:21:38Z

r? bjorn3

GuillaumeGomez

For what it's worth, changes look good to me.

View changes since this review

bjorn3 · 2026-10-02T11:25:27Z

    pattern_types,
-    thread_local
+    thread_local,
+    rustc_private


You will also need to change cg_gcc's build system to pass -Zforce-unstable-if-unmarked when testing mini_core and mini_core_hello_world. Otherwise this will result in a warning in cg_gcc's CI.

View changes since the review

You will also need to change cg_gcc's build system to pass -Zforce-unstable-if-unmarked

Why is that? Could we just add the missing features in the code?

If #![feature(rustc_private)] is not used, everything works, except when -Zforce-unstable-if-unmarked is used (as it unconditionally is when testing through bootstrap). If -Zforce-unstable-if-unmarked is used, then the const stability checker will require #![feature(rustc_private)] to be set as the size_of intrinsic gets marked as unstable(rustc_private), yet it doesn't take into account that the entire crate is unstable(rustc_private) like the regular stability checker. But if -Zforce-unstable-if-unmarked is not set, then #![feature(rustc_private)] would be unused as nothing would get marked as unstable(rustc_private).

Kobzol · 2026-10-04T17:49:27Z

@rustbot ready

bjorn3 · 2026-10-04T18:15:21Z

@bors r+

rust-bors · 2026-10-04T18:15:24Z

📌 Commit c3bee7b has been approved by bjorn3

It is now in the queue for this repository.

…uwer Rollup of 9 pull requests Successful merges: - #161491 (Rip out old solver coherence) - #163533 (Run cg_gcc tests with the correct compiler) - #163223 (regression test for async handler normalization ICE) - #163367 (simplify rustc_log a bit) - #163622 (x86: c-variadic functions don't use registers with `-Zregparm`) - #163653 (callconv: mips64: Match GCC for alignment of 16-byte scalars) - #163665 (Parser: Refactor & better document `should_continue_as_assoc_expr` & `can_continue_expr_unambiguously`) - #163742 (Add the `movdir64b` and `movdiri` x86 target features) - #163752 (Revert "implement PartialEq<VecDeque<U>> for Vec<T>, &[T], &mut [T], [T; N], &[T; N] and &mut [T; N]")

@antoyo

Rollup merge of #163533 - Kobzol:cg-gcc-tests, r=bjorn3 Run cg_gcc tests with the correct compiler Seems like we have been running the tests with the stage 0 compiler all along :surprised: The tests crash with: ``` [BUILD] mini_core [BUILD] example [AOT] mini_core_hello_world warning: the feature `never_type` has been stable since 1.101.0-dev and no longer requires an attribute to enable --> example/mini_core_hello_world.rs:4:44 | 4 | no_core, unboxed_closures, lang_items, never_type, linkage, | ^^^^^^^^^^ | = note: `#[warn(stable_features)]` on by default thread 'rustc' (1671953) panicked at compiler/rustc_codegen_ssa/src/mir/rvalue.rs:1114:5: assertion `left == right` failed left: __int8_t * __attribute__((aligned(8))) right: void * stack backtrace: 0: __rustc::rust_begin_unwind at /rustc/cbae9b4cae2b108f6a3d18cfe6075714bb739463/library/std/src/panicking.rs:679:5 1: core::panicking::panic_fmt at /rustc/cbae9b4cae2b108f6a3d18cfe6075714bb739463/library/core/src/panicking.rs:80:14 2: core::panicking::assert_failed_inner at /rustc/cbae9b4cae2b108f6a3d18cfe6075714bb739463/library/core/src/panicking.rs:452:17 3: core::panicking::assert_failed::<gccjit::types::Type, gccjit::types::Type> at /rustc/cbae9b4cae2b108f6a3d18cfe6075714bb739463/library/core/src/panicking.rs:407:5 4: transmute_scalar<rustc_codegen_gcc::builder::Builder> 5: codegen_transmute_operand<rustc_codegen_gcc::builder::Builder> at /home/bjorn/rust/compiler/rustc_codegen_ssa/src/mir/rvalue.rs:419:21 6: codegen_rvalue_operand<rustc_codegen_gcc::builder::Builder> at /home/bjorn/rust/compiler/rustc_codegen_ssa/src/mir/rvalue.rs:625:30 7: codegen_statement<rustc_codegen_gcc::builder::Builder> at /home/bjorn/rust/compiler/rustc_codegen_ssa/src/mir/statement.rs:37:52 ``` I'll need help with resolving that from the cg_gcc side (CC @antoyo). Fixes: #163527

@antoyo

Run cg_gcc tests with the correct compiler Seems like we have been running the tests with the stage 0 compiler all along :surprised: The tests crash with: ``` [BUILD] mini_core [BUILD] example [AOT] mini_core_hello_world warning: the feature `never_type` has been stable since 1.101.0-dev and no longer requires an attribute to enable --> example/mini_core_hello_world.rs:4:44 | 4 | no_core, unboxed_closures, lang_items, never_type, linkage, | ^^^^^^^^^^ | = note: `#[warn(stable_features)]` on by default thread 'rustc' (1671953) panicked at compiler/rustc_codegen_ssa/src/mir/rvalue.rs:1114:5: assertion `left == right` failed left: __int8_t * __attribute__((aligned(8))) right: void * stack backtrace: 0: __rustc::rust_begin_unwind at /rustc/cbae9b4cae2b108f6a3d18cfe6075714bb739463/library/std/src/panicking.rs:679:5 1: core::panicking::panic_fmt at /rustc/cbae9b4cae2b108f6a3d18cfe6075714bb739463/library/core/src/panicking.rs:80:14 2: core::panicking::assert_failed_inner at /rustc/cbae9b4cae2b108f6a3d18cfe6075714bb739463/library/core/src/panicking.rs:452:17 3: core::panicking::assert_failed::<gccjit::types::Type, gccjit::types::Type> at /rustc/cbae9b4cae2b108f6a3d18cfe6075714bb739463/library/core/src/panicking.rs:407:5 4: transmute_scalar<rustc_codegen_gcc::builder::Builder> 5: codegen_transmute_operand<rustc_codegen_gcc::builder::Builder> at /home/bjorn/rust/compiler/rustc_codegen_ssa/src/mir/rvalue.rs:419:21 6: codegen_rvalue_operand<rustc_codegen_gcc::builder::Builder> at /home/bjorn/rust/compiler/rustc_codegen_ssa/src/mir/rvalue.rs:625:30 7: codegen_statement<rustc_codegen_gcc::builder::Builder> at /home/bjorn/rust/compiler/rustc_codegen_ssa/src/mir/statement.rs:37:52 ``` I'll need help with resolving that from the cg_gcc side (CC @antoyo). Fixes: #163527

Kobzol added 2 commits September 30, 2026 12:10

Run cg_gcc tests with the in-tree compiler

1a60c28

Add rustc_private to cg_gcc examples

c7e5a82

Kobzol mentioned this pull request Sep 30, 2026

./x.py test compiler/rustc_codegen_gcc is broken #163527

Closed

Kobzol marked this pull request as ready for review October 2, 2026 10:21

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 Oct 2, 2026

rustbot assigned Mark-Simulacrum Oct 2, 2026

rustbot assigned bjorn3 and unassigned Mark-Simulacrum Oct 2, 2026

GuillaumeGomez approved these changes Oct 2, 2026

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bjorn3 reviewed Oct 2, 2026

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Comment thread src/bootstrap/src/core/build_steps/test.rs

Add warning about debug assertions

d3c88b4

Kobzol force-pushed the cg-gcc-tests branch from 4d00eca to d3c88b4 Compare October 2, 2026 10:36

bjorn3 reviewed Oct 2, 2026

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bjorn3 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 Oct 2, 2026

Pass -Zforce-unstable-if-unmarked when building cg_gcc's minitests

c3bee7b

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 Oct 4, 2026

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 Oct 4, 2026

JonathanBrouwer mentioned this pull request Oct 4, 2026

Rollup of 9 pull requests #163767

Merged

rust-bors Bot merged commit 762d317 into rust-lang:main Oct 4, 2026
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rustbot added this to the 1.101.0 milestone Oct 4, 2026

Kobzol deleted the cg-gcc-tests branch October 5, 2026 06:27

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