Auto merge of #144658 - jhpratt:rollup-jdzhz27, r=jhpratt

Rollup of 8 pull requests

Successful merges:

 - rust-lang/rust#144034 (tests: Test line number in debuginfo for diverging function calls)
 - rust-lang/rust#144510 (Fix Ord, Eq and Hash implementation of panic::Location)
 - rust-lang/rust#144583 (Enable T-compiler backport nomination)
 - rust-lang/rust#144586 (Update wasi-sdk to 27.0 in CI)
 - rust-lang/rust#144605 (Resolve: cachify `ExternPreludeEntry.binding` through a `Cell`)
 - rust-lang/rust#144632 (Update some tests for LLVM 21)
 - rust-lang/rust#144639 (Update rustc-perf submodule)
 - rust-lang/rust#144640 (Add support for the m68k architecture in 'object_architecture')

r? `@ghost`
`@rustbot` modify labels: rollup

17 files changed, 234 insertions, 54 deletions

diff --git a/compiler/rustc_resolve/src/build_reduced_graph.rs b/compiler/rustc_resolve/src/build_reduced_graph.rs
index b15b478a6be..7912345ec56 100644
--- a/compiler/rustc_resolve/src/build_reduced_graph.rs
+++ b/compiler/rustc_resolve/src/build_reduced_graph.rs
@@ -984,18 +984,17 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
                 // more details: https://github.com/rust-lang/rust/pull/111761
                 return;
             }
-            let entry = self
-                .r
-                .extern_prelude
-                .entry(ident)
-                .or_insert(ExternPreludeEntry { binding: None, introduced_by_item: true });
+            let entry = self.r.extern_prelude.entry(ident).or_insert(ExternPreludeEntry {
+                binding: Cell::new(None),
+                introduced_by_item: true,
+            });
             if orig_name.is_some() {
                 entry.introduced_by_item = true;
             }
             // Binding from `extern crate` item in source code can replace
             // a binding from `--extern` on command line here.
             if !entry.is_import() {
-                entry.binding = Some(imported_binding)
+                entry.binding.set(Some(imported_binding));
             } else if ident.name != kw::Underscore {
                 self.r.dcx().span_delayed_bug(
                     item.span,
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 8115b87dcae..88dfb50b47d 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -1009,13 +1009,13 @@ impl<'ra> NameBindingData<'ra> {
 
 #[derive(Default, Clone)]
 struct ExternPreludeEntry<'ra> {
-    binding: Option<NameBinding<'ra>>,
+    binding: Cell<Option<NameBinding<'ra>>>,
     introduced_by_item: bool,
 }
 
 impl ExternPreludeEntry<'_> {
     fn is_import(&self) -> bool {
-        self.binding.is_some_and(|binding| binding.is_import())
+        self.binding.get().is_some_and(|binding| binding.is_import())
     }
 }
 
@@ -2006,7 +2006,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             // but not introduce it, as used if they are accessed from lexical scope.
             if used == Used::Scope {
                 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
-                    if !entry.introduced_by_item && entry.binding == Some(used_binding) {
+                    if !entry.introduced_by_item && entry.binding.get() == Some(used_binding) {
                         return;
                     }
                 }
@@ -2170,7 +2170,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
 
         let norm_ident = ident.normalize_to_macros_2_0();
         let binding = self.extern_prelude.get(&norm_ident).cloned().and_then(|entry| {
-            Some(if let Some(binding) = entry.binding {
+            Some(if let Some(binding) = entry.binding.get() {
                 if finalize {
                     if !entry.is_import() {
                         self.cstore_mut().process_path_extern(self.tcx, ident.name, ident.span);
@@ -2195,8 +2195,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             })
         });
 
-        if let Some(entry) = self.extern_prelude.get_mut(&norm_ident) {
-            entry.binding = binding;
+        if let Some(entry) = self.extern_prelude.get(&norm_ident) {
+            entry.binding.set(binding);
         }
 
         binding
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index c64cd9a51b7..033590e01a6 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -3598,6 +3598,7 @@ impl Target {
             ),
             "x86" => (Architecture::I386, None),
             "s390x" => (Architecture::S390x, None),
+            "m68k" => (Architecture::M68k, None),
             "mips" | "mips32r6" => (Architecture::Mips, None),
             "mips64" | "mips64r6" => (
                 // While there are currently no builtin targets
diff --git a/library/core/src/panic/location.rs b/library/core/src/panic/location.rs
index 97227020885..6ef7d5a22a3 100644
--- a/library/core/src/panic/location.rs
+++ b/library/core/src/panic/location.rs
@@ -1,5 +1,7 @@
+use crate::cmp::Ordering;
 use crate::ffi::CStr;
 use crate::fmt;
+use crate::hash::{Hash, Hasher};
 use crate::marker::PhantomData;
 use crate::ptr::NonNull;
 
@@ -32,7 +34,7 @@ use crate::ptr::NonNull;
 /// Files are compared as strings, not `Path`, which could be unexpected.
 /// See [`Location::file`]'s documentation for more discussion.
 #[lang = "panic_location"]
-#[derive(Copy, Clone, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[derive(Copy, Clone)]
 #[stable(feature = "panic_hooks", since = "1.10.0")]
 pub struct Location<'a> {
     // A raw pointer is used rather than a reference because the pointer is valid for one more byte
@@ -45,6 +47,44 @@ pub struct Location<'a> {
 }
 
 #[stable(feature = "panic_hooks", since = "1.10.0")]
+impl PartialEq for Location<'_> {
+    fn eq(&self, other: &Self) -> bool {
+        // Compare col / line first as they're cheaper to compare and more likely to differ,
+        // while not impacting the result.
+        self.col == other.col && self.line == other.line && self.file() == other.file()
+    }
+}
+
+#[stable(feature = "panic_hooks", since = "1.10.0")]
+impl Eq for Location<'_> {}
+
+#[stable(feature = "panic_hooks", since = "1.10.0")]
+impl Ord for Location<'_> {
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.file()
+            .cmp(other.file())
+            .then_with(|| self.line.cmp(&other.line))
+            .then_with(|| self.col.cmp(&other.col))
+    }
+}
+
+#[stable(feature = "panic_hooks", since = "1.10.0")]
+impl PartialOrd for Location<'_> {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+#[stable(feature = "panic_hooks", since = "1.10.0")]
+impl Hash for Location<'_> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.file().hash(state);
+        self.line.hash(state);
+        self.col.hash(state);
+    }
+}
+
+#[stable(feature = "panic_hooks", since = "1.10.0")]
 impl fmt::Debug for Location<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("Location")
diff --git a/library/coretests/tests/panic/location.rs b/library/coretests/tests/panic/location.rs
index 5ce0b06e90e..910001bcc1c 100644
--- a/library/coretests/tests/panic/location.rs
+++ b/library/coretests/tests/panic/location.rs
@@ -3,6 +3,23 @@ use core::panic::Location;
 // Note: Some of the following tests depend on the source location,
 // so please be careful when editing this file.
 
+mod file_a;
+mod file_b;
+mod file_c;
+
+// A small shuffled set of locations for testing, along with their true order.
+const LOCATIONS: [(usize, &'static Location<'_>); 9] = [
+    (7, file_c::two()),
+    (0, file_a::one()),
+    (3, file_b::one()),
+    (5, file_b::three()),
+    (8, file_c::three()),
+    (6, file_c::one()),
+    (2, file_a::three()),
+    (4, file_b::two()),
+    (1, file_a::two()),
+];
+
 #[test]
 fn location_const_caller() {
     const _CALLER_REFERENCE: &Location<'static> = Location::caller();
@@ -20,7 +37,7 @@ fn location_const_file() {
 fn location_const_line() {
     const CALLER: &Location<'static> = Location::caller();
     const LINE: u32 = CALLER.line();
-    assert_eq!(LINE, 21);
+    assert_eq!(LINE, 38);
 }
 
 #[test]
@@ -34,6 +51,28 @@ fn location_const_column() {
 fn location_debug() {
     let f = format!("{:?}", Location::caller());
     assert!(f.contains(&format!("{:?}", file!())));
-    assert!(f.contains("35"));
+    assert!(f.contains("52"));
     assert!(f.contains("29"));
 }
+
+#[test]
+fn location_eq() {
+    for (i, a) in LOCATIONS {
+        for (j, b) in LOCATIONS {
+            if i == j {
+                assert_eq!(a, b);
+            } else {
+                assert_ne!(a, b);
+            }
+        }
+    }
+}
+
+#[test]
+fn location_ord() {
+    let mut locations = LOCATIONS.clone();
+    locations.sort_by_key(|(_o, l)| **l);
+    for (correct, (order, _l)) in locations.iter().enumerate() {
+        assert_eq!(correct, *order);
+    }
+}
diff --git a/library/coretests/tests/panic/location/file_a.rs b/library/coretests/tests/panic/location/file_a.rs
new file mode 100644
index 00000000000..1ceb225ee9c
--- /dev/null
+++ b/library/coretests/tests/panic/location/file_a.rs
@@ -0,0 +1,15 @@
+use core::panic::Location;
+
+// Used for test super::location_{ord, eq}. Must be in a dedicated file.
+
+pub const fn one() -> &'static Location<'static> {
+    Location::caller()
+}
+
+pub const fn two() -> &'static Location<'static> {
+    Location::caller()
+}
+
+pub const fn three() -> &'static Location<'static> {
+    Location::caller()
+}
diff --git a/library/coretests/tests/panic/location/file_b.rs b/library/coretests/tests/panic/location/file_b.rs
new file mode 100644
index 00000000000..1ceb225ee9c
--- /dev/null
+++ b/library/coretests/tests/panic/location/file_b.rs
@@ -0,0 +1,15 @@
+use core::panic::Location;
+
+// Used for test super::location_{ord, eq}. Must be in a dedicated file.
+
+pub const fn one() -> &'static Location<'static> {
+    Location::caller()
+}
+
+pub const fn two() -> &'static Location<'static> {
+    Location::caller()
+}
+
+pub const fn three() -> &'static Location<'static> {
+    Location::caller()
+}
diff --git a/library/coretests/tests/panic/location/file_c.rs b/library/coretests/tests/panic/location/file_c.rs
new file mode 100644
index 00000000000..2ac416c19cf
--- /dev/null
+++ b/library/coretests/tests/panic/location/file_c.rs
@@ -0,0 +1,11 @@
+// Used for test super::location_{ord, eq}. Must be in a dedicated file.
+
+// This is used for testing column ordering of Location, hence this ugly one-liner.
+// We must fmt skip the entire containing module or else tidy will still complain.
+#[rustfmt::skip]
+mod no_fmt {
+    use core::panic::Location;
+    pub const fn one() -> &'static Location<'static> { Location::caller() }    pub const fn two() -> &'static Location<'static> { Location::caller() }    pub const fn three() -> &'static Location<'static> { Location::caller() }
+}
+
+pub use no_fmt::*;
diff --git a/src/ci/docker/host-x86_64/dist-various-2/Dockerfile b/src/ci/docker/host-x86_64/dist-various-2/Dockerfile
index e1d83d36087..0855ea222a3 100644
--- a/src/ci/docker/host-x86_64/dist-various-2/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-various-2/Dockerfile
@@ -81,9 +81,9 @@ RUN /tmp/build-fuchsia-toolchain.sh
 COPY host-x86_64/dist-various-2/build-x86_64-fortanix-unknown-sgx-toolchain.sh /tmp/
 RUN /tmp/build-x86_64-fortanix-unknown-sgx-toolchain.sh
 
-RUN curl -L https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-25/wasi-sdk-25.0-x86_64-linux.tar.gz | \
+RUN curl -L https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-27/wasi-sdk-27.0-x86_64-linux.tar.gz | \
   tar -xz
-ENV WASI_SDK_PATH=/tmp/wasi-sdk-25.0-x86_64-linux
+ENV WASI_SDK_PATH=/tmp/wasi-sdk-27.0-x86_64-linux
 
 COPY scripts/freebsd-toolchain.sh /tmp/
 RUN /tmp/freebsd-toolchain.sh i686
diff --git a/src/ci/docker/host-x86_64/test-various/Dockerfile b/src/ci/docker/host-x86_64/test-various/Dockerfile
index 662a26400ce..82a820c859d 100644
--- a/src/ci/docker/host-x86_64/test-various/Dockerfile
+++ b/src/ci/docker/host-x86_64/test-various/Dockerfile
@@ -40,9 +40,9 @@ WORKDIR /
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
-RUN curl -L https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-25/wasi-sdk-25.0-x86_64-linux.tar.gz | \
+RUN curl -L https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-27/wasi-sdk-27.0-x86_64-linux.tar.gz | \
   tar -xz
-ENV WASI_SDK_PATH=/wasi-sdk-25.0-x86_64-linux
+ENV WASI_SDK_PATH=/wasi-sdk-27.0-x86_64-linux
 
 ENV RUST_CONFIGURE_ARGS \
   --musl-root-x86_64=/usr/local/x86_64-linux-musl \
diff --git a/src/tools/rustc-perf b/src/tools/rustc-perf
-Subproject 6a70166b92a1b1560cb3cf056427b011b2a1f2b
+Subproject dde879cf1087cb34a32287bd8ccc4d545bb9fee
diff --git a/src/tools/tidy/src/deps.rs b/src/tools/tidy/src/deps.rs
index 8e2a796106f..858b058cb7d 100644
--- a/src/tools/tidy/src/deps.rs
+++ b/src/tools/tidy/src/deps.rs
@@ -167,7 +167,7 @@ const EXCEPTIONS_RUSTC_PERF: ExceptionList = &[
     ("brotli-decompressor", "BSD-3-Clause/MIT"),
     ("encoding_rs", "(Apache-2.0 OR MIT) AND BSD-3-Clause"),
     ("inferno", "CDDL-1.0"),
-    ("ring", NON_STANDARD_LICENSE), // see EXCEPTIONS_NON_STANDARD_LICENSE_DEPS for more.
+    ("option-ext", "MPL-2.0"),
     ("ryu", "Apache-2.0 OR BSL-1.0"),
     ("snap", "BSD-3-Clause"),
     ("subtle", "BSD-3-Clause"),
@@ -226,20 +226,6 @@ const EXCEPTIONS_UEFI_QEMU_TEST: ExceptionList = &[
     ("r-efi", "MIT OR Apache-2.0 OR LGPL-2.1-or-later"), // LGPL is not acceptable, but we use it under MIT OR Apache-2.0
 ];
 
-/// Placeholder for non-standard license file.
-const NON_STANDARD_LICENSE: &str = "NON_STANDARD_LICENSE";
-
-/// These dependencies have non-standard licenses but are genenrally permitted.
-const EXCEPTIONS_NON_STANDARD_LICENSE_DEPS: &[&str] = &[
-    // `ring` is included because it is an optional dependency of `hyper`,
-    // which is a training data in rustc-perf for optimized build.
-    // The license of it is generally `ISC AND MIT AND OpenSSL`,
-    // though the `package.license` field is not set.
-    //
-    // See https://github.com/briansmith/ring/issues/902
-    "ring",
-];
-
 const PERMITTED_DEPS_LOCATION: &str = concat!(file!(), ":", line!());
 
 /// Crates rustc is allowed to depend on. Avoid adding to the list if possible.
@@ -599,7 +585,7 @@ pub fn check(root: &Path, cargo: &Path, bless: bool, bad: &mut bool) {
             .other_options(vec!["--locked".to_owned()]);
         let metadata = t!(cmd.exec());
 
-        check_license_exceptions(&metadata, exceptions, bad);
+        check_license_exceptions(&metadata, workspace, exceptions, bad);
         if let Some((crates, permitted_deps)) = permitted_deps {
             check_permitted_dependencies(&metadata, workspace, permitted_deps, crates, bad);
         }
@@ -730,14 +716,19 @@ fn check_runtime_license_exceptions(metadata: &Metadata, bad: &mut bool) {
 /// Check that all licenses of tool dependencies are in the valid list in `LICENSES`.
 ///
 /// Packages listed in `exceptions` are allowed for tools.
-fn check_license_exceptions(metadata: &Metadata, exceptions: &[(&str, &str)], bad: &mut bool) {
+fn check_license_exceptions(
+    metadata: &Metadata,
+    workspace: &str,
+    exceptions: &[(&str, &str)],
+    bad: &mut bool,
+) {
     // Validate the EXCEPTIONS list hasn't changed.
     for (name, license) in exceptions {
         // Check that the package actually exists.
         if !metadata.packages.iter().any(|p| *p.name == *name) {
             tidy_error!(
                 bad,
-                "could not find exception package `{}`\n\
+                "could not find exception package `{}` in workspace `{workspace}`\n\
                 Remove from EXCEPTIONS list if it is no longer used.",
                 name
             );
@@ -746,20 +737,17 @@ fn check_license_exceptions(metadata: &Metadata, exceptions: &[(&str, &str)], ba
         for pkg in metadata.packages.iter().filter(|p| *p.name == *name) {
             match &pkg.license {
                 None => {
-                    if *license == NON_STANDARD_LICENSE
-                        && EXCEPTIONS_NON_STANDARD_LICENSE_DEPS.contains(&pkg.name.as_str())
-                    {
-                        continue;
-                    }
                     tidy_error!(
                         bad,
-                        "dependency exception `{}` does not declare a license expression",
+                        "dependency exception `{}` in workspace `{workspace}` does not declare a license expression",
                         pkg.id
                     );
                 }
                 Some(pkg_license) => {
                     if pkg_license.as_str() != *license {
-                        println!("dependency exception `{name}` license has changed");
+                        println!(
+                            "dependency exception `{name}` license in workspace `{workspace}` has changed"
+                        );
                         println!("    previously `{license}` now `{pkg_license}`");
                         println!("    update EXCEPTIONS for the new license");
                         *bad = true;
@@ -783,12 +771,21 @@ fn check_license_exceptions(metadata: &Metadata, exceptions: &[(&str, &str)], ba
         let license = match &pkg.license {
             Some(license) => license,
             None => {
-                tidy_error!(bad, "dependency `{}` does not define a license expression", pkg.id);
+                tidy_error!(
+                    bad,
+                    "dependency `{}` in workspace `{workspace}` does not define a license expression",
+                    pkg.id
+                );
                 continue;
             }
         };
         if !LICENSES.contains(&license.as_str()) {
-            tidy_error!(bad, "invalid license `{}` in `{}`", license, pkg.id);
+            tidy_error!(
+                bad,
+                "invalid license `{}` for package `{}` in workspace `{workspace}`",
+                license,
+                pkg.id
+            );
         }
     }
 }
diff --git a/tests/assembly-llvm/nvptx-safe-naming.rs b/tests/assembly-llvm/nvptx-safe-naming.rs
index d7b46aadd9c..6a6659a4e30 100644
--- a/tests/assembly-llvm/nvptx-safe-naming.rs
+++ b/tests/assembly-llvm/nvptx-safe-naming.rs
@@ -1,6 +1,9 @@
 //@ assembly-output: ptx-linker
 //@ compile-flags: --crate-type cdylib -Z unstable-options -Clinker-flavor=llbc
 //@ only-nvptx64
+//@ revisions: LLVM20 LLVM21
+//@ [LLVM21] min-llvm-version: 21
+//@ [LLVM20] max-llvm-major-version: 20
 
 #![feature(abi_ptx)]
 #![no_std]
@@ -15,7 +18,8 @@ extern crate breakpoint_panic_handler;
 #[no_mangle]
 pub unsafe extern "ptx-kernel" fn top_kernel(a: *const u32, b: *mut u32) {
     // CHECK:      call.uni (retval0),
-    // CHECK-NEXT: [[IMPL_FN]]
+    // LLVM20-NEXT: [[IMPL_FN]]
+    // LLVM21-SAME: [[IMPL_FN]]
     *b = deep::private::MyStruct::new(*a).square();
 }
 
diff --git a/tests/assembly-llvm/x86-return-float.rs b/tests/assembly-llvm/x86-return-float.rs
index 165c11d2280..4db93f68485 100644
--- a/tests/assembly-llvm/x86-return-float.rs
+++ b/tests/assembly-llvm/x86-return-float.rs
@@ -334,9 +334,9 @@ pub fn return_f128(x: f128) -> f128 {
     // linux-NEXT: .cfi_offset
     // CHECK-NEXT: movl %esp, %ebp
     // linux-NEXT: .cfi_def_cfa_register
-    // linux-NEXT: movaps 8(%ebp), %xmm0
-    // win-NEXT: movups 8(%ebp), %xmm0
-    // CHECK-NEXT: popl %ebp
+    // linux: movaps 8(%ebp), %xmm0
+    // win: movups 8(%ebp), %xmm0
+    // CHECK: popl %ebp
     // linux-NEXT: .cfi_def_cfa
     // CHECK-NEXT: retl
     x
diff --git a/tests/codegen-llvm/diverging-function-call-debuginfo.rs b/tests/codegen-llvm/diverging-function-call-debuginfo.rs
new file mode 100644
index 00000000000..1a80fe1643d
--- /dev/null
+++ b/tests/codegen-llvm/diverging-function-call-debuginfo.rs
@@ -0,0 +1,38 @@
+/// Make sure that line debuginfo is correct for diverging calls under certain
+/// conditions. In particular we want to ensure that the line number is never
+/// 0, but we check the absence of 0 by looking for the expected exact line
+/// numbers. Regression test for <https://github.com/rust-lang/rust/issues/59558>.
+
+//@ compile-flags: -g -Clto -Copt-level=0
+//@ no-prefer-dynamic
+
+// First find the scope of both diverge() calls, namely this main() function.
+// CHECK-DAG: [[MAIN_SCOPE:![0-9]+]] = distinct !DISubprogram(name: "main", linkageName: {{.*}}diverging_function_call_debuginfo{{.*}}main{{.*}}
+fn main() {
+    if True == False {
+        // unreachable
+        // Then find the DILocation with the correct line number for this call ...
+        // CHECK-DAG: [[UNREACHABLE_CALL_DBG:![0-9]+]] = !DILocation(line: [[@LINE+1]], {{.*}}scope: [[MAIN_SCOPE]]
+        diverge();
+    }
+
+    // ... and this call.
+    // CHECK-DAG: [[LAST_CALL_DBG:![0-9]+]] = !DILocation(line: [[@LINE+1]], {{.*}}scope: [[MAIN_SCOPE]]
+    diverge();
+}
+
+#[derive(PartialEq)]
+pub enum MyBool {
+    True,
+    False,
+}
+
+use MyBool::*;
+
+fn diverge() -> ! {
+    panic!();
+}
+
+// Finally make sure both DILocations belong to each the respective diverge() call.
+// CHECK-DAG: call void {{.*}}diverging_function_call_debuginfo{{.*}}diverge{{.*}} !dbg [[LAST_CALL_DBG]]
+// CHECK-DAG: call void {{.*}}diverging_function_call_debuginfo{{.*}}diverge{{.*}} !dbg [[UNREACHABLE_CALL_DBG]]
diff --git a/tests/codegen-llvm/enum/enum-discriminant-eq.rs b/tests/codegen-llvm/enum/enum-discriminant-eq.rs
index 0494c5f551b..d599685c2e5 100644
--- a/tests/codegen-llvm/enum/enum-discriminant-eq.rs
+++ b/tests/codegen-llvm/enum/enum-discriminant-eq.rs
@@ -1,6 +1,9 @@
 //@ compile-flags: -Copt-level=3 -Zmerge-functions=disabled
 //@ min-llvm-version: 20
 //@ only-64bit
+//@ revisions: LLVM20 LLVM21
+//@ [LLVM21] min-llvm-version: 21
+//@ [LLVM20] max-llvm-major-version: 20
 
 // The `derive(PartialEq)` on enums with field-less variants compares discriminants,
 // so make sure we emit that in some reasonable way.
@@ -137,17 +140,20 @@ pub fn mid_nz32_eq_discr(a: Mid<NonZero<u32>>, b: Mid<NonZero<u32>>) -> bool {
 pub fn mid_ac_eq_discr(a: Mid<AC>, b: Mid<AC>) -> bool {
     // CHECK-LABEL: @mid_ac_eq_discr(
 
-    // CHECK: %[[A_REL_DISCR:.+]] = xor i8 %a, -128
+    // LLVM20: %[[A_REL_DISCR:.+]] = xor i8 %a, -128
     // CHECK: %[[A_IS_NICHE:.+]] = icmp slt i8 %a, 0
     // CHECK: %[[A_NOT_HOLE:.+]] = icmp ne i8 %a, -127
     // CHECK: tail call void @llvm.assume(i1 %[[A_NOT_HOLE]])
-    // CHECK: %[[A_DISCR:.+]] = select i1 %[[A_IS_NICHE]], i8 %[[A_REL_DISCR]], i8 1
+    // LLVM20: %[[A_DISCR:.+]] = select i1 %[[A_IS_NICHE]], i8 %[[A_REL_DISCR]], i8 1
 
-    // CHECK: %[[B_REL_DISCR:.+]] = xor i8 %b, -128
+    // LLVM20: %[[B_REL_DISCR:.+]] = xor i8 %b, -128
     // CHECK: %[[B_IS_NICHE:.+]] = icmp slt i8 %b, 0
     // CHECK: %[[B_NOT_HOLE:.+]] = icmp ne i8 %b, -127
     // CHECK: tail call void @llvm.assume(i1 %[[B_NOT_HOLE]])
-    // CHECK: %[[B_DISCR:.+]] = select i1 %[[B_IS_NICHE]], i8 %[[B_REL_DISCR]], i8 1
+    // LLVM20: %[[B_DISCR:.+]] = select i1 %[[B_IS_NICHE]], i8 %[[B_REL_DISCR]], i8 1
+
+    // LLVM21: %[[A_DISCR:.+]] = select i1 %[[A_IS_NICHE]], i8 %a, i8 -127
+    // LLVM21: %[[B_DISCR:.+]] = select i1 %[[B_IS_NICHE]], i8 %b, i8 -127
 
     // CHECK: %[[R:.+]] = icmp eq i8 %[[A_DISCR]], %[[B_DISCR]]
     // CHECK: ret i1 %[[R]]
diff --git a/triagebot.toml b/triagebot.toml
index 894f56df741..e1b4983adf7 100644
--- a/triagebot.toml
+++ b/triagebot.toml
@@ -50,6 +50,21 @@ remove_labels = ["S-waiting-on-author"]
 # Those labels are added when PR author requests a review from an assignee
 add_labels = ["S-waiting-on-review"]
 
+# [backport.*] sections autonominate pull requests for a backport
+# see: https://forge.rust-lang.org/triagebot/backport.html
+
+[backport.t-compiler-beta-backport]
+# The pull request MUST have one of these labels
+required-pr-labels = ["T-compiler"]
+# The regression MUST have this label
+required-issue-label = "regression-from-stable-to-beta"
+# if the above conditions matches, the PR will receive these labels
+add-labels = ["beta-nominated"]
+
+[backport.t-compiler-stable-backport]
+required-pr-labels = ["T-compiler"]
+required-issue-label = "regression-from-stable-to-stable"
+add-labels = ["stable-nominated"]
 
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 # Ping groups