diff --git a/library/compiler-builtins/builtins-test/Cargo.toml b/library/compiler-builtins/builtins-test/Cargo.toml
index b3227b5751164..84912fe16df92 100644
--- a/library/compiler-builtins/builtins-test/Cargo.toml
+++ b/library/compiler-builtins/builtins-test/Cargo.toml
@@ -39,7 +39,7 @@ walltime = ["dep:criterion"]
 
 [lints.clippy]
 # This sometimes reads better
-needless-range-loop = "allow"
+needless_range_loop = "allow"
 
 [[bench]]
 name = "float_add"
diff --git a/library/compiler-builtins/builtins-test/src/lib.rs b/library/compiler-builtins/builtins-test/src/lib.rs
index ebd0162dfae05..5f4bf35942af7 100644
--- a/library/compiler-builtins/builtins-test/src/lib.rs
+++ b/library/compiler-builtins/builtins-test/src/lib.rs
@@ -24,6 +24,9 @@ use compiler_builtins::support::{Float, Int, MinInt};
 use rand_xoshiro::Xoshiro128StarStar;
 use rand_xoshiro::rand_core::{Rng, SeedableRng};
 
+// Workaround for Cargo unused dependency lint false positive
+use rustc_apfloat as _;
+
 /// Sets the number of fuzz iterations run for most tests. In practice, the vast majority of bugs
 /// are caught by the edge case testers. Most of the remaining bugs triggered by more complex
 /// sequences are caught well within 10_000 fuzz iterations. For classes of algorithms like division
diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index 70a97c8b87826..dea408a4cfddb 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -3746,6 +3746,108 @@ impl CommandLineStep for Crate {
     }
 }
 
+/// Test compiler-builtins via its testcrate.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct CompilerBuiltins {
+    compiler: Compiler,
+    target: TargetSelection,
+}
+
+impl CommandLineStep for CompilerBuiltins {
+    type Output = ();
+
+    fn is_default_step(_builder: &Builder<'_>) -> bool {
+        true
+    }
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        run.alias("compiler-builtins")
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        let builder = run.builder;
+        let host = run.build_triple();
+        let compiler = builder.compiler(builder.top_stage, host);
+
+        builder.ensure(CompilerBuiltins { compiler, target: run.target });
+    }
+
+    fn run(self, builder: &Builder<'_>) -> Self::Output {
+        let compiler = self.compiler;
+        let target = self.target;
+        let record_failed_tests = builder.ensure(SetupFailedTestsFile);
+
+        builder.ensure(compile::Std::new(compiler, compiler.host));
+        builder.ensure(compile::Std::new(compiler, target));
+
+        const COMPILER_BUILTINS_ALLOW_FEATURES: &[&str] = &[
+            // tidy-alphabetical-start
+            "abi_custom",
+            "asm_experimental_arch",
+            "cfg_target_has_atomic",
+            "compiler_builtins",
+            "compiler_builtins_lib",
+            "complex_numbers",
+            "core_intrinsics",
+            "decl_macro",
+            "f16",
+            "f128",
+            "lang_items",
+            "linkage",
+            "macro_metavar_expr_concat",
+            "repr_simd",
+            "rustc_attrs",
+            "rustc_private",
+            "wasm_numeric_instr",
+            // tidy-alphabetical-end
+        ];
+
+        let make_cargo = |f: fn(&mut builder::Cargo) -> &mut builder::Cargo| {
+            let mut cargo = builder::Cargo::new(
+                builder,
+                compiler,
+                Mode::ToolStd,
+                SourceType::InTree,
+                target,
+                Kind::Test,
+            );
+            // We have to run from the root directory to make offline builds work.
+            // We have to use the combined vendored dependencies
+            // from the `default_paths_to_vendor` function, rather than only the vendored
+            // dependencies of the standard library, which do not contain compiler-builtins
+            // dependencies.
+            cargo.arg("--manifest-path");
+            cargo.arg(builder.src.join("library").join("compiler-builtins").join("Cargo.toml"));
+            cargo.allow_features(&COMPILER_BUILTINS_ALLOW_FEATURES.join(","));
+            f(&mut cargo);
+            cargo
+        };
+
+        // Most tests are in the builtins-test crate.
+        let crates = ["compiler_builtins".to_string(), "builtins-test".to_string()];
+        let cargo = make_cargo(|c| c);
+        run_cargo_test(
+            cargo,
+            &[],
+            &crates,
+            "compiler-builtins",
+            target,
+            builder,
+            record_failed_tests.clone(),
+        );
+        let cargo = make_cargo(|c| c.arg("--features=c"));
+        run_cargo_test(
+            cargo,
+            &[],
+            &crates,
+            "compiler-builtins --features c",
+            target,
+            builder,
+            record_failed_tests,
+        );
+    }
+}
+
 /// Run cargo tests for the rustdoc crate.
 /// Rustdoc is special in various ways, which is why this step is different from `Crate`.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
diff --git a/src/bootstrap/src/core/build_steps/vendor.rs b/src/bootstrap/src/core/build_steps/vendor.rs
index 0d8ccc0d5b5c7..a91a729c6ef8c 100644
--- a/src/bootstrap/src/core/build_steps/vendor.rs
+++ b/src/bootstrap/src/core/build_steps/vendor.rs
@@ -25,6 +25,7 @@ pub fn default_paths_to_vendor(builder: &Builder<'_>) -> Vec<(PathBuf, Vec<&'sta
         ("compiler/rustc_codegen_gcc/Cargo.toml", vec![]),
         ("library/Cargo.toml", vec![]),
         ("library/stdarch/Cargo.toml", vec![]),
+        ("library/compiler-builtins/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 0967b604412e6..1fe97ca766c81 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
@@ -217,6 +217,9 @@ expression: test
 [Test] test::TestFloatParse
     targets: [aarch64-unknown-linux-gnu]
     - Set({src/tools/test-float-parse})
+[Test] test::CompilerBuiltins
+    targets: [aarch64-unknown-linux-gnu]
+    - Set({compiler-builtins})
 [Test] test::RunMake
     targets: [aarch64-unknown-linux-gnu]
     - Suite(tests/run-make)
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 cd835904b00d1..f112cdafa81b3 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
@@ -214,6 +214,9 @@ expression: test --skip=coverage
 [Test] test::TestFloatParse
     targets: [aarch64-unknown-linux-gnu]
     - Set({src/tools/test-float-parse})
+[Test] test::CompilerBuiltins
+    targets: [aarch64-unknown-linux-gnu]
+    - Set({compiler-builtins})
 [Test] test::RunMake
     targets: [aarch64-unknown-linux-gnu]
     - Suite(tests/run-make)
diff --git a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_coverage_map.snap b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_coverage_map.snap
index 0801bdf09328f..401cdc8432d2f 100644
--- a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_coverage_map.snap
+++ b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_coverage_map.snap
@@ -217,6 +217,9 @@ expression: test --skip=coverage-map
 [Test] test::TestFloatParse
     targets: [aarch64-unknown-linux-gnu]
     - Set({src/tools/test-float-parse})
+[Test] test::CompilerBuiltins
+    targets: [aarch64-unknown-linux-gnu]
+    - Set({compiler-builtins})
 [Test] test::RunMake
     targets: [aarch64-unknown-linux-gnu]
     - Suite(tests/run-make)
diff --git a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_coverage_run.snap b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_coverage_run.snap
index d7ec4e55cc710..01d5b362e928f 100644
--- a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_coverage_run.snap
+++ b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_coverage_run.snap
@@ -217,6 +217,9 @@ expression: test --skip=coverage-run
 [Test] test::TestFloatParse
     targets: [aarch64-unknown-linux-gnu]
     - Set({src/tools/test-float-parse})
+[Test] test::CompilerBuiltins
+    targets: [aarch64-unknown-linux-gnu]
+    - Set({compiler-builtins})
 [Test] test::RunMake
     targets: [aarch64-unknown-linux-gnu]
     - Suite(tests/run-make)
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 bee21f9fd3b91..b936eeefe8805 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
@@ -163,6 +163,9 @@ expression: test --skip=tests
 [Test] test::TestFloatParse
     targets: [aarch64-unknown-linux-gnu]
     - Set({src/tools/test-float-parse})
+[Test] test::CompilerBuiltins
+    targets: [aarch64-unknown-linux-gnu]
+    - Set({compiler-builtins})
 [Test] test::IntrinsicTest
     targets: [x86_64-unknown-linux-gnu]
     - Set({intrinsic-test})
diff --git a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_tests_coverage.snap b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_tests_coverage.snap
index afa6039d5cba2..c7ea1c663a030 100644
--- a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_tests_coverage.snap
+++ b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_tests_coverage.snap
@@ -214,6 +214,9 @@ expression: test --skip=tests/coverage
 [Test] test::TestFloatParse
     targets: [aarch64-unknown-linux-gnu]
     - Set({src/tools/test-float-parse})
+[Test] test::CompilerBuiltins
+    targets: [aarch64-unknown-linux-gnu]
+    - Set({compiler-builtins})
 [Test] test::RunMake
     targets: [aarch64-unknown-linux-gnu]
     - Suite(tests/run-make)
diff --git a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_tests_etc.snap b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_tests_etc.snap
index 20c8ec8b25a9a..98b39e619fad8 100644
--- a/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_tests_etc.snap
+++ b/src/bootstrap/src/core/builder/cli_paths/snapshots/x_test_skip_tests_etc.snap
@@ -143,6 +143,9 @@ expression: test --skip=tests --skip=library --skip=tidyselftest
 [Test] test::TestFloatParse
     targets: [aarch64-unknown-linux-gnu]
     - Set({src/tools/test-float-parse})
+[Test] test::CompilerBuiltins
+    targets: [aarch64-unknown-linux-gnu]
+    - Set({compiler-builtins})
 [Test] test::IntrinsicTest
     targets: [x86_64-unknown-linux-gnu]
     - Set({intrinsic-test})
diff --git a/src/bootstrap/src/core/builder/mod.rs b/src/bootstrap/src/core/builder/mod.rs
index 1359733089eee..44445fe74d3b0 100644
--- a/src/bootstrap/src/core/builder/mod.rs
+++ b/src/bootstrap/src/core/builder/mod.rs
@@ -938,6 +938,7 @@ impl<'a> Builder<'a> {
                 test::HtmlCheck,
                 test::RustInstaller,
                 test::TestFloatParse,
+                test::CompilerBuiltins,
                 test::CollectLicenseMetadata,
                 test::RunMake,
                 test::RunMakeCargo,