diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index c28fe4ad832d3..37a6398925b7c 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -904,6 +904,54 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
     }
 }
 
+/// Runs `library/stdarch/crates/stdarch-verify`'s tests which cross-check the
+/// `core::arch` intrinsics for x86, Arm, and MIPS against the corresponding
+/// vendor references (signatures, target features, and `assert_instr` mappings).
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct StdarchVerify;
+
+impl Step for StdarchVerify {
+    type Output = ();
+    const IS_HOST: bool = true;
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        run.path("library/stdarch/crates/stdarch-verify")
+    }
+
+    fn is_default_step(_builder: &Builder<'_>) -> bool {
+        true
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        run.builder.ensure(StdarchVerify);
+    }
+
+    fn run(self, builder: &Builder<'_>) {
+        let host = builder.config.host_target;
+        let build_compiler = builder.compiler(0, host);
+
+        let cargo = tool::prepare_tool_cargo(
+            builder,
+            build_compiler,
+            Mode::ToolBootstrap,
+            host,
+            Kind::Test,
+            "library/stdarch/crates/stdarch-verify",
+            SourceType::InTree,
+            &[],
+        );
+
+        run_cargo_test(
+            cargo,
+            &[],
+            &["stdarch-verify".to_string()],
+            Some("stdarch-verify"),
+            host,
+            builder,
+        );
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Clippy {
     compilers: RustcPrivateCompilers,
diff --git a/src/bootstrap/src/core/build_steps/vendor.rs b/src/bootstrap/src/core/build_steps/vendor.rs
index 17bee20a525b6..519f134bb8203 100644
--- a/src/bootstrap/src/core/build_steps/vendor.rs
+++ b/src/bootstrap/src/core/build_steps/vendor.rs
@@ -24,6 +24,7 @@ pub fn default_paths_to_vendor(builder: &Builder<'_>) -> Vec<(PathBuf, Vec<&'sta
         ("compiler/rustc_codegen_cranelift/Cargo.toml", vec![]),
         ("compiler/rustc_codegen_gcc/Cargo.toml", vec![]),
         ("library/Cargo.toml", vec![]),
+        ("library/stdarch/Cargo.toml", vec![]),
         ("src/bootstrap/Cargo.toml", vec![]),
         ("src/tools/rustbook/Cargo.toml", SUBMODULES_FOR_RUSTBOOK.into()),
         ("src/tools/rustc-perf/Cargo.toml", vec!["src/tools/rustc-perf"]),
diff --git a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test.snap b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test.snap
index 25ff1e64e76b4..60e8a219585c6 100644
--- a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test.snap
+++ b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test.snap
@@ -181,6 +181,9 @@ expression: test
 [Test] test::RustcBook
     targets: [x86_64-unknown-linux-gnu]
     - Set({test::src/doc/rustc})
+[Test] test::StdarchVerify
+    targets: [x86_64-unknown-linux-gnu]
+    - Set({test::library/stdarch/crates/stdarch-verify})
 [Test] test::RustdocJSStd
     targets: [x86_64-unknown-linux-gnu]
     - Suite(test::tests/rustdoc-js-std)
diff --git a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_library.snap b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_library.snap
index dfc397597a877..f97bb839c1e73 100644
--- a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_library.snap
+++ b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_library.snap
@@ -18,3 +18,6 @@ expression: test library
     - Set({test::library/sysroot})
     - Set({test::library/test})
     - Set({test::library/unwind})
+[Test] test::StdarchVerify
+    targets: [x86_64-unknown-linux-gnu]
+    - Set({test::library/stdarch/crates/stdarch-verify})
diff --git a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_coverage.snap b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_coverage.snap
index 2f1ee9386ed72..fb83986445bea 100644
--- a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_coverage.snap
+++ b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_coverage.snap
@@ -180,6 +180,9 @@ expression: test --skip=coverage
 [Test] test::RustcBook
     targets: [x86_64-unknown-linux-gnu]
     - Set({test::src/doc/rustc})
+[Test] test::StdarchVerify
+    targets: [x86_64-unknown-linux-gnu]
+    - Set({test::library/stdarch/crates/stdarch-verify})
 [Test] test::RustdocJSStd
     targets: [x86_64-unknown-linux-gnu]
     - Suite(test::tests/rustdoc-js-std)
diff --git a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_tests.snap b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_tests.snap
index 8f5e842d28a15..3737272dd83a4 100644
--- a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_tests.snap
+++ b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_tests.snap
@@ -144,6 +144,9 @@ expression: test --skip=tests
 [Test] test::RustcBook
     targets: [x86_64-unknown-linux-gnu]
     - Set({test::src/doc/rustc})
+[Test] test::StdarchVerify
+    targets: [x86_64-unknown-linux-gnu]
+    - Set({test::library/stdarch/crates/stdarch-verify})
 [Test] test::RustdocTheme
     targets: [x86_64-unknown-linux-gnu]
     - Set({test::src/tools/rustdoc-themes})
diff --git a/src/bootstrap/src/core/builder/mod.rs b/src/bootstrap/src/core/builder/mod.rs
index bc402313367fd..2e640220efd8e 100644
--- a/src/bootstrap/src/core/builder/mod.rs
+++ b/src/bootstrap/src/core/builder/mod.rs
@@ -910,6 +910,7 @@ impl<'a> Builder<'a> {
                 test::CargoMiri,
                 test::Clippy,
                 test::CompiletestTest,
+                test::StdarchVerify,
                 test::CrateRunMakeSupport,
                 test::CrateBuildHelper,
                 test::RustdocJSStd,
diff --git a/src/tools/tidy/src/deps.rs b/src/tools/tidy/src/deps.rs
index 2b12e653f3748..ef08286122916 100644
--- a/src/tools/tidy/src/deps.rs
+++ b/src/tools/tidy/src/deps.rs
@@ -132,6 +132,12 @@ pub(crate) const WORKSPACES: &[WorkspaceInfo<'static>] = &[
         )),
         submodules: &[],
     },
+    WorkspaceInfo {
+        path: "library/stdarch",
+        exceptions: EXCEPTIONS_STDARCH,
+        crates_and_deps: None,
+        submodules: &[],
+    },
     WorkspaceInfo {
         path: "compiler/rustc_codegen_cranelift",
         exceptions: EXCEPTIONS_CRANELIFT,
@@ -254,6 +260,8 @@ const EXCEPTIONS_RUSTBOOK: ExceptionList = &[
     // tidy-alphabetical-end
 ];
 
+const EXCEPTIONS_STDARCH: ExceptionList = &[];
+
 const EXCEPTIONS_CRANELIFT: ExceptionList = &[];
 
 const EXCEPTIONS_GCC: ExceptionList = &[