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Tie extern "llvm-intrinsics" and llvm.* symbol names together - #161922

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Tie extern "llvm-intrinsics" and llvm.* symbol names together#161922
bjorn3 wants to merge 1 commit into
rust-lang:mainfrom
bjorn3:tie_llvm_intrinsic_abi_and_name

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@bjorn3

@bjorn3 bjorn3 commented Aug 28, 2026

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LLVM intrinsics must always use extern "llvm-intrinsic" and extern "llvm-intrinsic" must only be used for actual LLVM intrinsics.

Follow up to #161398

@bjorn3
Tie extern "llvm-intrinsics" and llvm.* symbol names together
6abfc6e 
LLVM intrinsics must always use extern "llvm-intrinsic" and
extern "llvm-intrinsic" must only be used for actual LLVM intrinsics.
@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. labels Aug 28, 2026
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rustbot commented Aug 28, 2026

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r? @ShoyuVanilla

rustbot has assigned @ShoyuVanilla.
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@bjorn3

bjorn3 commented Aug 28, 2026

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Not sure if this is the best place to do this check.

@rust-log-analyzer

rust-log-analyzer commented Aug 28, 2026

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The job aarch64-gnu-llvm-21-1 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot) 
---- [ui] tests/ui/scalable-vectors/debuginfo-does-not-spill.rs stdout ----

error: test compilation failed although it shouldn't!
status: exit status: 101
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/scalable-vectors/debuginfo-does-not-spill.rs" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2" "--target=aarch64-unknown-linux-gnu" "--check-cfg" "cfg(test,FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/scalable-vectors/debuginfo-does-not-spill" "-Znext-solver=coherence" "-A" "unused" "-W" "unused_attributes" "-A" "internal_features" "-A" "incomplete_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers" "--edition=2021" "-C" "debuginfo=2" "-C" "target-feature=+sve"
stdout: none
--- stderr -------------------------------
##[error]error: internal compiler error: compiler/rustc_monomorphize/src/mono_checks/abi_check.rs:258:17: llvm.* function must use `extern "llvm-intrinsic"`
  --> /checkout/tests/ui/scalable-vectors/debuginfo-does-not-spill.rs:38:14
   |
LL |     unsafe { _svwhilelt_b32_u64(op1, op2) }.into()
   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^


thread 'rustc' (130768) panicked at compiler/rustc_monomorphize/src/mono_checks/abi_check.rs:258:17:
Box<dyn Any>
stack backtrace:
   0: std::panicking::begin_panic::<rustc_errors::ExplicitBug>
   1: <rustc_errors::diagnostic::BugAbort as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
   2: <rustc_errors::DiagCtxtHandle>::span_bug::<rustc_span::span_encoding::Span, alloc::string::String>
   3: rustc_middle::util::bug::opt_span_bug_fmt::<rustc_span::span_encoding::Span>::{closure#0}
   4: rustc_middle::ty::context::tls::with_opt::<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}
   5: rustc_middle::ty::context::tls::with_context_opt::<rustc_middle::ty::context::tls::with_opt<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
   6: rustc_middle::util::bug::span_bug_fmt::<rustc_span::span_encoding::Span>
   7: rustc_monomorphize::mono_checks::abi_check::check_feature_dependent_abi
   8: rustc_monomorphize::mono_checks::check_mono_item
      [... omitted 2 frames ...]
   9: rustc_monomorphize::collector::items_of_instance
      [... omitted 2 frames ...]
  10: rustc_monomorphize::collector::collect_items_rec
  11: rustc_monomorphize::collector::collect_items_root
  12: std::panicking::catch_unwind::<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_data_structures::sync::parallel::par_for_each_in<rustc_middle::mono::MonoItem, alloc::vec::Vec<rustc_middle::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#1}::{closure#0}>>
  13: <rustc_data_structures::sync::parallel::ParallelGuard>::run::<(), rustc_data_structures::sync::parallel::par_for_each_in<rustc_middle::mono::MonoItem, alloc::vec::Vec<rustc_middle::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#1}::{closure#0}>
  14: <alloc::vec::into_iter::IntoIter<rustc_middle::mono::MonoItem> as core::iter::traits::iterator::Iterator>::fold::<(), core::iter::traits::iterator::Iterator::for_each::call<rustc_middle::mono::MonoItem, rustc_data_structures::sync::parallel::par_for_each_in<rustc_middle::mono::MonoItem, alloc::vec::Vec<rustc_middle::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#1}>::{closure#0}>
  15: rustc_data_structures::sync::parallel::par_for_each_in::<rustc_middle::mono::MonoItem, alloc::vec::Vec<rustc_middle::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>
  16: <rustc_session::session::Session>::time::<(), rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}>
  17: rustc_monomorphize::collector::collect_crate_mono_items
  18: rustc_monomorphize::partitioning::collect_and_partition_mono_items
      [... omitted 2 frames ...]
  19: rustc_codegen_ssa::back::symbol_export::exported_generic_symbols_provider_local
      [... omitted 2 frames ...]
  20: <rustc_metadata::rmeta::encoder::EncodeContext>::encode_crate_root
  21: rustc_metadata::rmeta::encoder::encode_metadata::{closure#3}::{closure#0}
  22: rustc_metadata::rmeta::encoder::with_encode_metadata_header::<rustc_metadata::rmeta::encoder::encode_metadata::{closure#3}::{closure#0}>
  23: rustc_metadata::rmeta::encoder::encode_metadata
  24: rustc_metadata::fs::encode_and_write_metadata
  25: rustc_interface::passes::start_codegen
  26: <rustc_interface::queries::Linker>::codegen_and_build_linker
  27: std::panicking::catch_unwind::<core::option::Option<rustc_interface::queries::Linker>, core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}>::{closure#2}::{closure#0}>>
  28: <std::thread::local::LocalKey<core::cell::Cell<*const ()>>>::with::<rustc_middle::ty::context::tls::enter_context<<rustc_middle::ty::context::GlobalCtxt>::enter<rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}>::{closure#2}, core::option::Option<rustc_interface::queries::Linker>>::{closure#1}, core::option::Option<rustc_interface::queries::Linker>>::{closure#0}, core::option::Option<rustc_interface::queries::Linker>>
  29: <rustc_middle::ty::context::TyCtxt>::create_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}>::{closure#2}>
  30: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}>
  31: std::panicking::catch_unwind::<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#2}::{closure#0}>>
  32: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#2}
  33: rustc_span::create_session_globals_then::<(), rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

note: using internal features is not supported and expected to cause internal compiler errors when used incorrectly

note: rustc 1.100.0-nightly (052ab1582 2026-08-28) running on aarch64-unknown-linux-gnu

note: compiler flags: -Z simulate-remapped-rust-src-base=/rustc/FAKE_PREFIX -Z translate-remapped-path-to-local-path=no -Z ignore-directory-in-diagnostics-source-blocks=/cargo -Z ignore-directory-in-diagnostics-source-blocks=/checkout/vendor -C codegen-units=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z write-long-types-to-disk=no -C strip=debuginfo -C prefer-dynamic -Z next-solver=coherence -C rpath -C debuginfo=2 -C target-feature=+sve

query stack during panic:
#0 [check_mono_item] monomorphization-time checking
#1 [items_of_instance] collecting items used by `svwhilelt_b32_u64`
#2 [collect_and_partition_mono_items] collect_and_partition_mono_items
#3 [exported_generic_symbols] collecting exported generic symbols for crate `0`
end of query stack
error: aborting due to 1 previous error
------------------------------------------

---- [ui] tests/ui/scalable-vectors/debuginfo-does-not-spill.rs stdout end ----
---- [ui] tests/ui/scalable-vectors/require-target-feature.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit status: 101
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/scalable-vectors/require-target-feature.rs" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2" "--check-cfg" "cfg(test,FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/scalable-vectors/require-target-feature" "-Znext-solver=coherence" "-A" "unused" "-W" "unused_attributes" "-A" "internal_features" "-A" "incomplete_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers" "-Cpanic=abort" "-Cforce-unwind-tables=yes" "--crate-type=lib" "--target=aarch64-unknown-linux-gnu" "--extern" "minicore=/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/scalable-vectors/require-target-feature/libminicore.rlib"
stdout: none
--- stderr -------------------------------
warning: `extern` block uses type `svint32_t`, which is not FFI-safe
##[warning]  --> /checkout/tests/ui/scalable-vectors/require-target-feature.rs:30:37
   |
LL |         fn _svdup_n_s32(op: i32) -> svint32_t;
   |                                     ^^^^^^^^^ not FFI-safe
   |
   = help: consider adding a `#[repr(C)]` or `#[repr(transparent)]` attribute to this struct
   = note: this struct has unspecified layout
note: the type is defined here
  --> /checkout/tests/ui/scalable-vectors/require-target-feature.rs:21:1
   |
LL | pub struct svint32_t(i32);
   | ^^^^^^^^^^^^^^^^^^^^
   = note: `#[warn(improper_ctypes)]` on by default

##[error]error: internal compiler error: compiler/rustc_monomorphize/src/mono_checks/abi_check.rs:258:17: llvm.* function must use `extern "llvm-intrinsic"`
  --> /checkout/tests/ui/scalable-vectors/require-target-feature.rs:33:14
   |
LL |     unsafe { _svdup_n_s32(op) }
   |              ^^^^^^^^^^^^^^^^


thread 'rustc' (130886) panicked at compiler/rustc_monomorphize/src/mono_checks/abi_check.rs:258:17:
Box<dyn Any>
stack backtrace:
   0: std::panicking::begin_panic::<rustc_errors::ExplicitBug>
   1: <rustc_errors::diagnostic::BugAbort as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
   2: <rustc_errors::DiagCtxtHandle>::span_bug::<rustc_span::span_encoding::Span, alloc::string::String>
   3: rustc_middle::util::bug::opt_span_bug_fmt::<rustc_span::span_encoding::Span>::{closure#0}
   4: rustc_middle::ty::context::tls::with_opt::<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}
   5: rustc_middle::ty::context::tls::with_context_opt::<rustc_middle::ty::context::tls::with_opt<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
   6: rustc_middle::util::bug::span_bug_fmt::<rustc_span::span_encoding::Span>
   7: rustc_monomorphize::mono_checks::abi_check::check_feature_dependent_abi
   8: rustc_monomorphize::mono_checks::check_mono_item
      [... omitted 2 frames ...]
   9: rustc_monomorphize::collector::items_of_instance
      [... omitted 2 frames ...]
  10: rustc_monomorphize::collector::collect_items_rec
  11: rustc_monomorphize::collector::collect_items_root
  12: std::panicking::catch_unwind::<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_data_structures::sync::parallel::par_for_each_in<rustc_middle::mono::MonoItem, alloc::vec::Vec<rustc_middle::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#1}::{closure#0}>>
  13: <rustc_data_structures::sync::parallel::ParallelGuard>::run::<(), rustc_data_structures::sync::parallel::par_for_each_in<rustc_middle::mono::MonoItem, alloc::vec::Vec<rustc_middle::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#1}::{closure#0}>
  14: <alloc::vec::into_iter::IntoIter<rustc_middle::mono::MonoItem> as core::iter::traits::iterator::Iterator>::fold::<(), core::iter::traits::iterator::Iterator::for_each::call<rustc_middle::mono::MonoItem, rustc_data_structures::sync::parallel::par_for_each_in<rustc_middle::mono::MonoItem, alloc::vec::Vec<rustc_middle::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#1}>::{closure#0}>
  15: rustc_data_structures::sync::parallel::par_for_each_in::<rustc_middle::mono::MonoItem, alloc::vec::Vec<rustc_middle::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>
  16: <rustc_session::session::Session>::time::<(), rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}>
  17: rustc_monomorphize::collector::collect_crate_mono_items
  18: rustc_monomorphize::partitioning::collect_and_partition_mono_items
      [... omitted 2 frames ...]
  19: rustc_codegen_ssa::back::symbol_export::exported_generic_symbols_provider_local
      [... omitted 2 frames ...]
  20: <rustc_metadata::rmeta::encoder::EncodeContext>::encode_crate_root
  21: rustc_metadata::rmeta::encoder::encode_metadata::{closure#3}::{closure#0}
  22: rustc_metadata::rmeta::encoder::with_encode_metadata_header::<rustc_metadata::rmeta::encoder::encode_metadata::{closure#3}::{closure#0}>
  23: rustc_metadata::rmeta::encoder::encode_metadata
  24: rustc_metadata::fs::encode_and_write_metadata
  25: rustc_interface::passes::start_codegen
  26: <rustc_interface::queries::Linker>::codegen_and_build_linker
  27: std::panicking::catch_unwind::<core::option::Option<rustc_interface::queries::Linker>, core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}>::{closure#2}::{closure#0}>>
  28: <std::thread::local::LocalKey<core::cell::Cell<*const ()>>>::with::<rustc_middle::ty::context::tls::enter_context<<rustc_middle::ty::context::GlobalCtxt>::enter<rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}>::{closure#2}, core::option::Option<rustc_interface::queries::Linker>>::{closure#1}, core::option::Option<rustc_interface::queries::Linker>>::{closure#0}, core::option::Option<rustc_interface::queries::Linker>>
  29: <rustc_middle::ty::context::TyCtxt>::create_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}>::{closure#2}>
  30: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}>
  31: std::panicking::catch_unwind::<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#2}::{closure#0}>>
  32: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#2}
  33: rustc_span::create_session_globals_then::<(), rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

note: using internal features is not supported and expected to cause internal compiler errors when used incorrectly

note: rustc 1.100.0-nightly (052ab1582 2026-08-28) running on aarch64-unknown-linux-gnu

note: compiler flags: -Z simulate-remapped-rust-src-base=/rustc/FAKE_PREFIX -Z translate-remapped-path-to-local-path=no -Z ignore-directory-in-diagnostics-source-blocks=/cargo -Z ignore-directory-in-diagnostics-source-blocks=/checkout/vendor -C codegen-units=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z write-long-types-to-disk=no -C strip=debuginfo -C prefer-dynamic -Z next-solver=coherence -C rpath -C debuginfo=0 -C panic=abort -C force-unwind-tables=yes --crate-type lib

query stack during panic:
#0 [check_mono_item] monomorphization-time checking
#1 [items_of_instance] collecting items used by `svdup_n_s32`
#2 [collect_and_partition_mono_items] collect_and_partition_mono_items
#3 [exported_generic_symbols] collecting exported generic symbols for crate `0`
end of query stack
error: this function definition requires the `sve` target feature, which is not enabled
##[error]  --> /checkout/tests/ui/scalable-vectors/require-target-feature.rs:36:1
   |
LL | pub fn non_annotated_callee(x: svint32_t) {}
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function defined here
   |
   = note: the function has type `svint32_t` in its signature, which is passed in scalable vector registers under the "Rust" ABI
   = help: consider enabling the missing target feature globally (`-C target-feature=+sve`) or locally (`#[target_feature(enable="sve")]`)

error: aborting due to 2 previous errors; 1 warning emitted
------------------------------------------

---- [ui] tests/ui/scalable-vectors/require-target-feature.rs stdout end ----
---- [ui] tests/ui/scalable-vectors/value-type.rs stdout ----

error: test compilation failed although it shouldn't!
status: exit status: 101
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/scalable-vectors/value-type.rs" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2" "--target=aarch64-unknown-linux-gnu" "--check-cfg" "cfg(test,FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/scalable-vectors/value-type" "-Znext-solver=coherence" "-A" "unused" "-W" "unused_attributes" "-A" "internal_features" "-A" "incomplete_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers" "--crate-type=lib"
stdout: none
--- stderr -------------------------------
warning: `extern` block uses type `svint32_t`, which is not FFI-safe
##[warning]  --> /checkout/tests/ui/scalable-vectors/value-type.rs:20:37
   |
LL |         fn _svdup_n_s32(op: i32) -> svint32_t;
   |                                     ^^^^^^^^^ not FFI-safe
   |
   = help: consider adding a `#[repr(C)]` or `#[repr(transparent)]` attribute to this struct
   = note: this struct has unspecified layout
note: the type is defined here
  --> /checkout/tests/ui/scalable-vectors/value-type.rs:14:1
   |
LL | pub struct svint32_t(i32);
   | ^^^^^^^^^^^^^^^^^^^^
   = note: `#[warn(improper_ctypes)]` on by default

##[error]error: internal compiler error: compiler/rustc_monomorphize/src/mono_checks/abi_check.rs:258:17: llvm.* function must use `extern "llvm-intrinsic"`
  --> /checkout/tests/ui/scalable-vectors/value-type.rs:23:14
   |
LL |     unsafe { _svdup_n_s32(op) }
   |              ^^^^^^^^^^^^^^^^


thread 'rustc' (130888) panicked at compiler/rustc_monomorphize/src/mono_checks/abi_check.rs:258:17:
Box<dyn Any>
stack backtrace:
   0: std::panicking::begin_panic::<rustc_errors::ExplicitBug>
   1: <rustc_errors::diagnostic::BugAbort as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
   2: <rustc_errors::DiagCtxtHandle>::span_bug::<rustc_span::span_encoding::Span, alloc::string::String>
   3: rustc_middle::util::bug::opt_span_bug_fmt::<rustc_span::span_encoding::Span>::{closure#0}
   4: rustc_middle::ty::context::tls::with_opt::<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}
   5: rustc_middle::ty::context::tls::with_context_opt::<rustc_middle::ty::context::tls::with_opt<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
   6: rustc_middle::util::bug::span_bug_fmt::<rustc_span::span_encoding::Span>
   7: rustc_monomorphize::mono_checks::abi_check::check_feature_dependent_abi
   8: rustc_monomorphize::mono_checks::check_mono_item
      [... omitted 2 frames ...]
   9: rustc_monomorphize::collector::items_of_instance
      [... omitted 2 frames ...]
  10: rustc_monomorphize::collector::collect_items_rec
  11: rustc_monomorphize::collector::collect_items_root
  12: std::panicking::catch_unwind::<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_data_structures::sync::parallel::par_for_each_in<rustc_middle::mono::MonoItem, alloc::vec::Vec<rustc_middle::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#1}::{closure#0}>>
  13: <rustc_data_structures::sync::parallel::ParallelGuard>::run::<(), rustc_data_structures::sync::parallel::par_for_each_in<rustc_middle::mono::MonoItem, alloc::vec::Vec<rustc_middle::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#1}::{closure#0}>
  14: <alloc::vec::into_iter::IntoIter<rustc_middle::mono::MonoItem> as core::iter::traits::iterator::Iterator>::fold::<(), core::iter::traits::iterator::Iterator::for_each::call<rustc_middle::mono::MonoItem, rustc_data_structures::sync::parallel::par_for_each_in<rustc_middle::mono::MonoItem, alloc::vec::Vec<rustc_middle::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#1}>::{closure#0}>
  15: rustc_data_structures::sync::parallel::par_for_each_in::<rustc_middle::mono::MonoItem, alloc::vec::Vec<rustc_middle::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>
  16: <rustc_session::session::Session>::time::<(), rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}>
  17: rustc_monomorphize::collector::collect_crate_mono_items
  18: rustc_monomorphize::partitioning::collect_and_partition_mono_items
      [... omitted 2 frames ...]
  19: rustc_codegen_ssa::back::symbol_export::exported_generic_symbols_provider_local
      [... omitted 2 frames ...]
  20: <rustc_metadata::rmeta::encoder::EncodeContext>::encode_crate_root
  21: rustc_metadata::rmeta::encoder::encode_metadata::{closure#3}::{closure#0}
  22: rustc_metadata::rmeta::encoder::with_encode_metadata_header::<rustc_metadata::rmeta::encoder::encode_metadata::{closure#3}::{closure#0}>
  23: rustc_metadata::rmeta::encoder::encode_metadata
  24: rustc_metadata::fs::encode_and_write_metadata
  25: rustc_interface::passes::start_codegen
  26: <rustc_interface::queries::Linker>::codegen_and_build_linker
  27: std::panicking::catch_unwind::<core::option::Option<rustc_interface::queries::Linker>, core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}>::{closure#2}::{closure#0}>>
  28: <std::thread::local::LocalKey<core::cell::Cell<*const ()>>>::with::<rustc_middle::ty::context::tls::enter_context<<rustc_middle::ty::context::GlobalCtxt>::enter<rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}>::{closure#2}, core::option::Option<rustc_interface::queries::Linker>>::{closure#1}, core::option::Option<rustc_interface::queries::Linker>>::{closure#0}, core::option::Option<rustc_interface::queries::Linker>>
  29: <rustc_middle::ty::context::TyCtxt>::create_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}>::{closure#2}>
  30: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}>
  31: std::panicking::catch_unwind::<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#2}::{closure#0}>>
  32: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#2}
  33: rustc_span::create_session_globals_then::<(), rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

note: using internal features is not supported and expected to cause internal compiler errors when used incorrectly

note: rustc 1.100.0-nightly (052ab1582 2026-08-28) running on aarch64-unknown-linux-gnu

note: compiler flags: -Z simulate-remapped-rust-src-base=/rustc/FAKE_PREFIX -Z translate-remapped-path-to-local-path=no -Z ignore-directory-in-diagnostics-source-blocks=/cargo -Z ignore-directory-in-diagnostics-source-blocks=/checkout/vendor -C codegen-units=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z write-long-types-to-disk=no -C strip=debuginfo -C prefer-dynamic -Z next-solver=coherence -C rpath -C debuginfo=0 --crate-type lib

query stack during panic:
#0 [check_mono_item] monomorphization-time checking
#1 [items_of_instance] collecting items used by `svdup_n_s32`
#2 [collect_and_partition_mono_items] collect_and_partition_mono_items
#3 [exported_generic_symbols] collecting exported generic symbols for crate `0`
end of query stack
error: aborting due to 1 previous error; 1 warning emitted
------------------------------------------

---- [ui] tests/ui/scalable-vectors/value-type.rs stdout end ----

@ShoyuVanilla

ShoyuVanilla commented Aug 28, 2026

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Sorry, I'm pretty ignorant about this area 😅

r? compiler

dingxiangfei2009
dingxiangfei2009 reviewed Aug 28, 2026
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Comment thread compiler/rustc_monomorphize/src/mono_checks/abi_check.rs
args.no_bound_vars().unwrap(),
DUMMY_SP,
);
if let InstanceKind::LlvmIntrinsic(..) = instance.def {

@dingxiangfei2009 dingxiangfei2009 Aug 28, 2026 •
edited by rustbot
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I suppose that let ... else would be able to shave off some indentation below and make your expectation clear. This is up to you.

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@dingxiangfei2009

dingxiangfei2009 commented Aug 28, 2026 •
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I reckon that the patch is incomplete. Are you going to "sanitize" the extern "llvm-intrinsics" declarations so that we don't hit the assertions? I can wait a bit.

@bjorn3

bjorn3 commented Aug 28, 2026

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Both extern "llvm-intrinsic" and #[link_name = "llvm.*"] are unstable features marked as internal. As such I think it is fine to ICE whenever you abuse them per rust-lang/compiler-team#620. But if you really want I can change them to fatal errors.

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