diff --git a/Cargo.lock b/Cargo.lock
index 90f73784cb4f7..af7c24abd132c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5988,9 +5988,9 @@ dependencies = [
 
 [[package]]
 name = "wasi-preview1-component-adapter-provider"
-version = "34.0.2"
+version = "36.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "33696c5f1ff1e083de9f36c3da471abd736362bc173e093f8b0b1ed5a387e39b"
+checksum = "20689c88791776219f78c2529700d15e6a9bd57a27858c62e9ef8487956b571c"
 
 [[package]]
 name = "wasm-bindgen"
@@ -6052,9 +6052,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-component-ld"
-version = "0.5.15"
+version = "0.5.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6d95124e34fee1316222e03b9bbf41af186ecbae2c8b79f8debe6e21b3ff60c5"
+checksum = "14cd35d6cae91109a0ffd207b573cf3c741cab7e921dd376ea7aaf2c52a3408c"
 dependencies = [
  "anyhow",
  "clap",
@@ -6062,7 +6062,7 @@ dependencies = [
  "libc",
  "tempfile",
  "wasi-preview1-component-adapter-provider",
- "wasmparser 0.234.0",
+ "wasmparser 0.237.0",
  "wat",
  "windows-sys 0.59.0",
  "winsplit",
@@ -6089,34 +6089,24 @@ dependencies = [
 
 [[package]]
 name = "wasm-encoder"
-version = "0.234.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "170a0157eef517a179f2d20ed7c68df9c3f7f6c1c047782d488bf5a464174684"
-dependencies = [
- "leb128fmt",
- "wasmparser 0.234.0",
-]
-
-[[package]]
-name = "wasm-encoder"
-version = "0.236.1"
+version = "0.237.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "724fccfd4f3c24b7e589d333fc0429c68042897a7e8a5f8694f31792471841e7"
+checksum = "efe92d1321afa53ffc88a57c497bb7330c3cf84c98ffdba4a4caf6a0684fad3c"
 dependencies = [
  "leb128fmt",
- "wasmparser 0.236.1",
+ "wasmparser 0.237.0",
 ]
 
 [[package]]
 name = "wasm-metadata"
-version = "0.234.0"
+version = "0.237.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a42fe3f5cbfb56fc65311ef827930d06189160038e81db62188f66b4bf468e3a"
+checksum = "4cc0b0a0c4f35ca6efa7a797671372915d4e9659dba2d59edc6fafc931d19997"
 dependencies = [
  "anyhow",
  "indexmap",
- "wasm-encoder 0.234.0",
- "wasmparser 0.234.0",
+ "wasm-encoder 0.237.0",
+ "wasmparser 0.237.0",
 ]
 
 [[package]]
@@ -6131,46 +6121,45 @@ dependencies = [
 
 [[package]]
 name = "wasmparser"
-version = "0.234.0"
+version = "0.236.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "be22e5a8f600afce671dd53c8d2dd26b4b7aa810fd18ae27dfc49737f3e02fc5"
+checksum = "a9b1e81f3eb254cf7404a82cee6926a4a3ccc5aad80cc3d43608a070c67aa1d7"
 dependencies = [
  "bitflags",
- "hashbrown",
  "indexmap",
- "semver",
- "serde",
 ]
 
 [[package]]
 name = "wasmparser"
-version = "0.236.1"
+version = "0.237.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a9b1e81f3eb254cf7404a82cee6926a4a3ccc5aad80cc3d43608a070c67aa1d7"
+checksum = "7d2a40ca0d2bdf4b0bf36c13a737d0b2c58e4c8aaefe1c57f336dd75369ca250"
 dependencies = [
  "bitflags",
+ "hashbrown",
  "indexmap",
  "semver",
+ "serde",
 ]
 
 [[package]]
 name = "wast"
-version = "236.0.1"
+version = "237.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d3bec4b4db9c6808d394632fd4b0cd4654c32c540bd3237f55ee6a40fff6e51f"
+checksum = "fcf66f545acbd55082485cb9a6daab54579cb8628a027162253e8e9f5963c767"
 dependencies = [
  "bumpalo",
  "leb128fmt",
  "memchr",
  "unicode-width 0.2.1",
- "wasm-encoder 0.236.1",
+ "wasm-encoder 0.237.0",
 ]
 
 [[package]]
 name = "wat"
-version = "1.236.1"
+version = "1.237.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "64475e2f77d6071ce90624098fc236285ddafa8c3ea1fb386f2c4154b6c2bbdb"
+checksum = "27975186f549e4b8d6878b627be732863883c72f7bf4dcf8f96e5f8242f73da9"
 dependencies = [
  "wast",
 ]
@@ -6659,9 +6648,9 @@ dependencies = [
 
 [[package]]
 name = "wit-component"
-version = "0.234.0"
+version = "0.237.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5a8888169acf4c6c4db535beb405b570eedac13215d6821ca9bd03190f7f8b8c"
+checksum = "bfb7674f76c10e82fe00b256a9d4ffb2b8d037d42ab8e9a83ebb3be35c9d0bf6"
 dependencies = [
  "anyhow",
  "bitflags",
@@ -6670,17 +6659,17 @@ dependencies = [
  "serde",
  "serde_derive",
  "serde_json",
- "wasm-encoder 0.234.0",
+ "wasm-encoder 0.237.0",
  "wasm-metadata",
- "wasmparser 0.234.0",
+ "wasmparser 0.237.0",
  "wit-parser",
 ]
 
 [[package]]
 name = "wit-parser"
-version = "0.234.0"
+version = "0.237.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "465492df47d8dcc015a3b7f241aed8ea03688fee7c5e04162285c5b1a3539c8b"
+checksum = "ce2596a5bc7c24cc965b56ad6ff9e32394c4e401764f89620a888519c6e849ab"
 dependencies = [
  "anyhow",
  "id-arena",
@@ -6691,7 +6680,7 @@ dependencies = [
  "serde_derive",
  "serde_json",
  "unicode-xid",
- "wasmparser 0.234.0",
+ "wasmparser 0.237.0",
 ]
 
 [[package]]
diff --git a/bootstrap.example.toml b/bootstrap.example.toml
index 4c18d5f8675dd..16fd9241a172a 100644
--- a/bootstrap.example.toml
+++ b/bootstrap.example.toml
@@ -407,8 +407,11 @@
 #build.profiler = false
 
 # Use the optimized LLVM C intrinsics for `compiler_builtins`, rather than Rust intrinsics.
-# Requires the LLVM submodule to be managed by bootstrap (i.e. not external) so that `compiler-rt`
-# sources are available.
+# Choosing true requires the LLVM submodule to be managed by bootstrap (i.e. not external)
+# so that `compiler-rt` sources are available.
+#
+# Setting this to a path removes the requirement for a C toolchain, but requires setting the
+# path to an existing library containing the builtins library from LLVM's compiler-rt.
 #
 # Setting this to `false` generates slower code, but removes the requirement for a C toolchain in
 # order to run `x check`.
@@ -1041,13 +1044,15 @@
 #runner = <none> (string)
 
 # Use the optimized LLVM C intrinsics for `compiler_builtins`, rather than Rust intrinsics
-# on this target.
-# Requires the LLVM submodule to be managed by bootstrap (i.e. not external) so that `compiler-rt`
-# sources are available.
+# on this target. Choosing true requires the LLVM submodule to be managed by bootstrap
+# (i.e. not external) so that `compiler-rt` sources are available.
+#
+# Setting this to a path removes the requirement for a C toolchain, but requires setting the
+# path to an existing library containing the builtins library from LLVM's compiler-rt.
 #
 # Setting this to `false` generates slower code, but removes the requirement for a C toolchain in
 # order to run `x check`.
-#optimized-compiler-builtins = build.optimized-compiler-builtins (bool)
+#optimized-compiler-builtins = build.optimized-compiler-builtins (bool or path)
 
 # Link the compiler and LLVM against `jemalloc` instead of the default libc allocator.
 # This overrides the global `rust.jemalloc` option. See that option for more info.
diff --git a/compiler/rustc_codegen_gcc/src/back/lto.rs b/compiler/rustc_codegen_gcc/src/back/lto.rs
index d558dfbc1c455..fcee6b6df6234 100644
--- a/compiler/rustc_codegen_gcc/src/back/lto.rs
+++ b/compiler/rustc_codegen_gcc/src/back/lto.rs
@@ -29,7 +29,7 @@ use rustc_codegen_ssa::back::write::{CodegenContext, FatLtoInput};
 use rustc_codegen_ssa::traits::*;
 use rustc_codegen_ssa::{ModuleCodegen, ModuleKind, looks_like_rust_object_file};
 use rustc_data_structures::memmap::Mmap;
-use rustc_errors::{DiagCtxtHandle, FatalError};
+use rustc_errors::DiagCtxtHandle;
 use rustc_middle::bug;
 use rustc_middle::dep_graph::WorkProduct;
 use rustc_session::config::Lto;
@@ -51,12 +51,11 @@ fn prepare_lto(
     cgcx: &CodegenContext<GccCodegenBackend>,
     each_linked_rlib_for_lto: &[PathBuf],
     dcx: DiagCtxtHandle<'_>,
-) -> Result<LtoData, FatalError> {
+) -> LtoData {
     let tmp_path = match tempdir() {
         Ok(tmp_path) => tmp_path,
         Err(error) => {
-            eprintln!("Cannot create temporary directory: {}", error);
-            return Err(FatalError);
+            dcx.fatal(format!("Cannot create temporary directory: {}", error));
         }
     };
 
@@ -91,15 +90,14 @@ fn prepare_lto(
                         upstream_modules.push((module, CString::new(name).unwrap()));
                     }
                     Err(e) => {
-                        dcx.emit_err(e);
-                        return Err(FatalError);
+                        dcx.emit_fatal(e);
                     }
                 }
             }
         }
     }
 
-    Ok(LtoData { upstream_modules, tmp_path })
+    LtoData { upstream_modules, tmp_path }
 }
 
 fn save_as_file(obj: &[u8], path: &Path) -> Result<(), LtoBitcodeFromRlib> {
@@ -114,10 +112,10 @@ pub(crate) fn run_fat(
     cgcx: &CodegenContext<GccCodegenBackend>,
     each_linked_rlib_for_lto: &[PathBuf],
     modules: Vec<FatLtoInput<GccCodegenBackend>>,
-) -> Result<ModuleCodegen<GccContext>, FatalError> {
+) -> ModuleCodegen<GccContext> {
     let dcx = cgcx.create_dcx();
     let dcx = dcx.handle();
-    let lto_data = prepare_lto(cgcx, each_linked_rlib_for_lto, dcx)?;
+    let lto_data = prepare_lto(cgcx, each_linked_rlib_for_lto, dcx);
     /*let symbols_below_threshold =
     lto_data.symbols_below_threshold.iter().map(|c| c.as_ptr()).collect::<Vec<_>>();*/
     fat_lto(
@@ -137,7 +135,7 @@ fn fat_lto(
     mut serialized_modules: Vec<(SerializedModule<ModuleBuffer>, CString)>,
     tmp_path: TempDir,
     //symbols_below_threshold: &[String],
-) -> Result<ModuleCodegen<GccContext>, FatalError> {
+) -> ModuleCodegen<GccContext> {
     let _timer = cgcx.prof.generic_activity("GCC_fat_lto_build_monolithic_module");
     info!("going for a fat lto");
 
@@ -261,7 +259,7 @@ fn fat_lto(
     // of now.
     module.module_llvm.temp_dir = Some(tmp_path);
 
-    Ok(module)
+    module
 }
 
 pub struct ModuleBuffer(PathBuf);
@@ -286,10 +284,10 @@ pub(crate) fn run_thin(
     each_linked_rlib_for_lto: &[PathBuf],
     modules: Vec<(String, ThinBuffer)>,
     cached_modules: Vec<(SerializedModule<ModuleBuffer>, WorkProduct)>,
-) -> Result<(Vec<ThinModule<GccCodegenBackend>>, Vec<WorkProduct>), FatalError> {
+) -> (Vec<ThinModule<GccCodegenBackend>>, Vec<WorkProduct>) {
     let dcx = cgcx.create_dcx();
     let dcx = dcx.handle();
-    let lto_data = prepare_lto(cgcx, each_linked_rlib_for_lto, dcx)?;
+    let lto_data = prepare_lto(cgcx, each_linked_rlib_for_lto, dcx);
     if cgcx.opts.cg.linker_plugin_lto.enabled() {
         unreachable!(
             "We should never reach this case if the LTO step \
@@ -355,7 +353,7 @@ fn thin_lto(
     tmp_path: TempDir,
     cached_modules: Vec<(SerializedModule<ModuleBuffer>, WorkProduct)>,
     //_symbols_below_threshold: &[String],
-) -> Result<(Vec<ThinModule<GccCodegenBackend>>, Vec<WorkProduct>), FatalError> {
+) -> (Vec<ThinModule<GccCodegenBackend>>, Vec<WorkProduct>) {
     let _timer = cgcx.prof.generic_activity("LLVM_thin_lto_global_analysis");
     info!("going for that thin, thin LTO");
 
@@ -518,13 +516,13 @@ fn thin_lto(
     // TODO: save the directory so that it gets deleted later.
     std::mem::forget(tmp_path);
 
-    Ok((opt_jobs, copy_jobs))
+    (opt_jobs, copy_jobs)
 }
 
 pub fn optimize_thin_module(
     thin_module: ThinModule<GccCodegenBackend>,
     _cgcx: &CodegenContext<GccCodegenBackend>,
-) -> Result<ModuleCodegen<GccContext>, FatalError> {
+) -> ModuleCodegen<GccContext> {
     //let dcx = cgcx.create_dcx();
 
     //let module_name = &thin_module.shared.module_names[thin_module.idx];
@@ -634,7 +632,8 @@ pub fn optimize_thin_module(
             save_temp_bitcode(cgcx, &module, "thin-lto-after-pm");
         }
     }*/
-    Ok(module)
+    #[allow(clippy::let_and_return)]
+    module
 }
 
 pub struct ThinBuffer {
diff --git a/compiler/rustc_codegen_gcc/src/back/write.rs b/compiler/rustc_codegen_gcc/src/back/write.rs
index c1231142c6585..84bc70162719f 100644
--- a/compiler/rustc_codegen_gcc/src/back/write.rs
+++ b/compiler/rustc_codegen_gcc/src/back/write.rs
@@ -6,7 +6,6 @@ use rustc_codegen_ssa::back::write::{BitcodeSection, CodegenContext, EmitObj, Mo
 use rustc_codegen_ssa::{CompiledModule, ModuleCodegen};
 use rustc_fs_util::link_or_copy;
 use rustc_session::config::OutputType;
-use rustc_span::fatal_error::FatalError;
 use rustc_target::spec::SplitDebuginfo;
 
 use crate::base::add_pic_option;
@@ -17,7 +16,7 @@ pub(crate) fn codegen(
     cgcx: &CodegenContext<GccCodegenBackend>,
     module: ModuleCodegen<GccContext>,
     config: &ModuleConfig,
-) -> Result<CompiledModule, FatalError> {
+) -> CompiledModule {
     let dcx = cgcx.create_dcx();
     let dcx = dcx.handle();
 
@@ -246,7 +245,7 @@ pub(crate) fn codegen(
         }
     }
 
-    Ok(module.into_compiled_module(
+    module.into_compiled_module(
         config.emit_obj != EmitObj::None,
         cgcx.target_can_use_split_dwarf && cgcx.split_debuginfo == SplitDebuginfo::Unpacked,
         config.emit_bc,
@@ -254,7 +253,7 @@ pub(crate) fn codegen(
         config.emit_ir,
         &cgcx.output_filenames,
         cgcx.invocation_temp.as_deref(),
-    ))
+    )
 }
 
 pub(crate) fn save_temp_bitcode(
diff --git a/compiler/rustc_codegen_gcc/src/lib.rs b/compiler/rustc_codegen_gcc/src/lib.rs
index 4025aba82da32..2d7df79ba95fa 100644
--- a/compiler/rustc_codegen_gcc/src/lib.rs
+++ b/compiler/rustc_codegen_gcc/src/lib.rs
@@ -110,7 +110,6 @@ use rustc_middle::util::Providers;
 use rustc_session::Session;
 use rustc_session::config::{OptLevel, OutputFilenames};
 use rustc_span::Symbol;
-use rustc_span::fatal_error::FatalError;
 use rustc_target::spec::RelocModel;
 use tempfile::TempDir;
 
@@ -362,7 +361,7 @@ impl WriteBackendMethods for GccCodegenBackend {
         _exported_symbols_for_lto: &[String],
         each_linked_rlib_for_lto: &[PathBuf],
         modules: Vec<FatLtoInput<Self>>,
-    ) -> Result<ModuleCodegen<Self::Module>, FatalError> {
+    ) -> ModuleCodegen<Self::Module> {
         back::lto::run_fat(cgcx, each_linked_rlib_for_lto, modules)
     }
 
@@ -373,7 +372,7 @@ impl WriteBackendMethods for GccCodegenBackend {
         each_linked_rlib_for_lto: &[PathBuf],
         modules: Vec<(String, Self::ThinBuffer)>,
         cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>,
-    ) -> Result<(Vec<ThinModule<Self>>, Vec<WorkProduct>), FatalError> {
+    ) -> (Vec<ThinModule<Self>>, Vec<WorkProduct>) {
         back::lto::run_thin(cgcx, each_linked_rlib_for_lto, modules, cached_modules)
     }
 
@@ -390,15 +389,14 @@ impl WriteBackendMethods for GccCodegenBackend {
         _dcx: DiagCtxtHandle<'_>,
         module: &mut ModuleCodegen<Self::Module>,
         config: &ModuleConfig,
-    ) -> Result<(), FatalError> {
+    ) {
         module.module_llvm.context.set_optimization_level(to_gcc_opt_level(config.opt_level));
-        Ok(())
     }
 
     fn optimize_thin(
         cgcx: &CodegenContext<Self>,
         thin: ThinModule<Self>,
-    ) -> Result<ModuleCodegen<Self::Module>, FatalError> {
+    ) -> ModuleCodegen<Self::Module> {
         back::lto::optimize_thin_module(thin, cgcx)
     }
 
@@ -406,7 +404,7 @@ impl WriteBackendMethods for GccCodegenBackend {
         cgcx: &CodegenContext<Self>,
         module: ModuleCodegen<Self::Module>,
         config: &ModuleConfig,
-    ) -> Result<CompiledModule, FatalError> {
+    ) -> CompiledModule {
         back::write::codegen(cgcx, module, config)
     }
 
diff --git a/compiler/rustc_codegen_llvm/src/back/lto.rs b/compiler/rustc_codegen_llvm/src/back/lto.rs
index 853d0295238e6..d85f432702cc5 100644
--- a/compiler/rustc_codegen_llvm/src/back/lto.rs
+++ b/compiler/rustc_codegen_llvm/src/back/lto.rs
@@ -14,7 +14,7 @@ use rustc_codegen_ssa::traits::*;
 use rustc_codegen_ssa::{ModuleCodegen, ModuleKind, looks_like_rust_object_file};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::memmap::Mmap;
-use rustc_errors::{DiagCtxtHandle, FatalError};
+use rustc_errors::DiagCtxtHandle;
 use rustc_middle::bug;
 use rustc_middle::dep_graph::WorkProduct;
 use rustc_session::config::{self, Lto};
@@ -36,7 +36,7 @@ fn prepare_lto(
     exported_symbols_for_lto: &[String],
     each_linked_rlib_for_lto: &[PathBuf],
     dcx: DiagCtxtHandle<'_>,
-) -> Result<(Vec<CString>, Vec<(SerializedModule<ModuleBuffer>, CString)>), FatalError> {
+) -> (Vec<CString>, Vec<(SerializedModule<ModuleBuffer>, CString)>) {
     let mut symbols_below_threshold = exported_symbols_for_lto
         .iter()
         .map(|symbol| CString::new(symbol.to_owned()).unwrap())
@@ -79,16 +79,13 @@ fn prepare_lto(
                         let module = SerializedModule::FromRlib(data.to_vec());
                         upstream_modules.push((module, CString::new(name).unwrap()));
                     }
-                    Err(e) => {
-                        dcx.emit_err(e);
-                        return Err(FatalError);
-                    }
+                    Err(e) => dcx.emit_fatal(e),
                 }
             }
         }
     }
 
-    Ok((symbols_below_threshold, upstream_modules))
+    (symbols_below_threshold, upstream_modules)
 }
 
 fn get_bitcode_slice_from_object_data<'a>(
@@ -123,11 +120,11 @@ pub(crate) fn run_fat(
     exported_symbols_for_lto: &[String],
     each_linked_rlib_for_lto: &[PathBuf],
     modules: Vec<FatLtoInput<LlvmCodegenBackend>>,
-) -> Result<ModuleCodegen<ModuleLlvm>, FatalError> {
+) -> ModuleCodegen<ModuleLlvm> {
     let dcx = cgcx.create_dcx();
     let dcx = dcx.handle();
     let (symbols_below_threshold, upstream_modules) =
-        prepare_lto(cgcx, exported_symbols_for_lto, each_linked_rlib_for_lto, dcx)?;
+        prepare_lto(cgcx, exported_symbols_for_lto, each_linked_rlib_for_lto, dcx);
     let symbols_below_threshold =
         symbols_below_threshold.iter().map(|c| c.as_ptr()).collect::<Vec<_>>();
     fat_lto(cgcx, dcx, modules, upstream_modules, &symbols_below_threshold)
@@ -142,11 +139,11 @@ pub(crate) fn run_thin(
     each_linked_rlib_for_lto: &[PathBuf],
     modules: Vec<(String, ThinBuffer)>,
     cached_modules: Vec<(SerializedModule<ModuleBuffer>, WorkProduct)>,
-) -> Result<(Vec<ThinModule<LlvmCodegenBackend>>, Vec<WorkProduct>), FatalError> {
+) -> (Vec<ThinModule<LlvmCodegenBackend>>, Vec<WorkProduct>) {
     let dcx = cgcx.create_dcx();
     let dcx = dcx.handle();
     let (symbols_below_threshold, upstream_modules) =
-        prepare_lto(cgcx, exported_symbols_for_lto, each_linked_rlib_for_lto, dcx)?;
+        prepare_lto(cgcx, exported_symbols_for_lto, each_linked_rlib_for_lto, dcx);
     let symbols_below_threshold =
         symbols_below_threshold.iter().map(|c| c.as_ptr()).collect::<Vec<_>>();
     if cgcx.opts.cg.linker_plugin_lto.enabled() {
@@ -173,7 +170,7 @@ fn fat_lto(
     modules: Vec<FatLtoInput<LlvmCodegenBackend>>,
     mut serialized_modules: Vec<(SerializedModule<ModuleBuffer>, CString)>,
     symbols_below_threshold: &[*const libc::c_char],
-) -> Result<ModuleCodegen<ModuleLlvm>, FatalError> {
+) -> ModuleCodegen<ModuleLlvm> {
     let _timer = cgcx.prof.generic_activity("LLVM_fat_lto_build_monolithic_module");
     info!("going for a fat lto");
 
@@ -224,7 +221,7 @@ fn fat_lto(
             assert!(!serialized_modules.is_empty(), "must have at least one serialized module");
             let (buffer, name) = serialized_modules.remove(0);
             info!("no in-memory regular modules to choose from, parsing {:?}", name);
-            let llvm_module = ModuleLlvm::parse(cgcx, &name, buffer.data(), dcx)?;
+            let llvm_module = ModuleLlvm::parse(cgcx, &name, buffer.data(), dcx);
             ModuleCodegen::new_regular(name.into_string().unwrap(), llvm_module)
         }
     };
@@ -265,7 +262,9 @@ fn fat_lto(
                 });
             info!("linking {:?}", name);
             let data = bc_decoded.data();
-            linker.add(data).map_err(|()| write::llvm_err(dcx, LlvmError::LoadBitcode { name }))?;
+            linker
+                .add(data)
+                .unwrap_or_else(|()| write::llvm_err(dcx, LlvmError::LoadBitcode { name }));
         }
         drop(linker);
         save_temp_bitcode(cgcx, &module, "lto.input");
@@ -282,7 +281,7 @@ fn fat_lto(
         save_temp_bitcode(cgcx, &module, "lto.after-restriction");
     }
 
-    Ok(module)
+    module
 }
 
 pub(crate) struct Linker<'a>(&'a mut llvm::Linker<'a>);
@@ -352,7 +351,7 @@ fn thin_lto(
     serialized_modules: Vec<(SerializedModule<ModuleBuffer>, CString)>,
     cached_modules: Vec<(SerializedModule<ModuleBuffer>, WorkProduct)>,
     symbols_below_threshold: &[*const libc::c_char],
-) -> Result<(Vec<ThinModule<LlvmCodegenBackend>>, Vec<WorkProduct>), FatalError> {
+) -> (Vec<ThinModule<LlvmCodegenBackend>>, Vec<WorkProduct>) {
     let _timer = cgcx.prof.generic_activity("LLVM_thin_lto_global_analysis");
     unsafe {
         info!("going for that thin, thin LTO");
@@ -422,7 +421,7 @@ fn thin_lto(
             symbols_below_threshold.as_ptr(),
             symbols_below_threshold.len(),
         )
-        .ok_or_else(|| write::llvm_err(dcx, LlvmError::PrepareThinLtoContext))?;
+        .unwrap_or_else(|| write::llvm_err(dcx, LlvmError::PrepareThinLtoContext));
 
         let data = ThinData(data);
 
@@ -492,10 +491,10 @@ fn thin_lto(
         if let Some(path) = key_map_path
             && let Err(err) = curr_key_map.save_to_file(&path)
         {
-            return Err(write::llvm_err(dcx, LlvmError::WriteThinLtoKey { err }));
+            write::llvm_err(dcx, LlvmError::WriteThinLtoKey { err });
         }
 
-        Ok((opt_jobs, copy_jobs))
+        (opt_jobs, copy_jobs)
     }
 }
 
@@ -550,7 +549,7 @@ pub(crate) fn run_pass_manager(
     dcx: DiagCtxtHandle<'_>,
     module: &mut ModuleCodegen<ModuleLlvm>,
     thin: bool,
-) -> Result<(), FatalError> {
+) {
     let _timer = cgcx.prof.generic_activity_with_arg("LLVM_lto_optimize", &*module.name);
     let config = cgcx.config(module.kind);
 
@@ -582,7 +581,7 @@ pub(crate) fn run_pass_manager(
     }
 
     unsafe {
-        write::llvm_optimize(cgcx, dcx, module, None, config, opt_level, opt_stage, stage)?;
+        write::llvm_optimize(cgcx, dcx, module, None, config, opt_level, opt_stage, stage);
     }
 
     if enable_gpu && !thin {
@@ -596,7 +595,7 @@ pub(crate) fn run_pass_manager(
         let stage = write::AutodiffStage::PostAD;
         if !config.autodiff.contains(&config::AutoDiff::NoPostopt) {
             unsafe {
-                write::llvm_optimize(cgcx, dcx, module, None, config, opt_level, opt_stage, stage)?;
+                write::llvm_optimize(cgcx, dcx, module, None, config, opt_level, opt_stage, stage);
             }
         }
 
@@ -608,7 +607,6 @@ pub(crate) fn run_pass_manager(
     }
 
     debug!("lto done");
-    Ok(())
 }
 
 pub struct ModuleBuffer(&'static mut llvm::ModuleBuffer);
@@ -701,7 +699,7 @@ impl Drop for ThinBuffer {
 pub(crate) fn optimize_thin_module(
     thin_module: ThinModule<LlvmCodegenBackend>,
     cgcx: &CodegenContext<LlvmCodegenBackend>,
-) -> Result<ModuleCodegen<ModuleLlvm>, FatalError> {
+) -> ModuleCodegen<ModuleLlvm> {
     let dcx = cgcx.create_dcx();
     let dcx = dcx.handle();
 
@@ -712,7 +710,7 @@ pub(crate) fn optimize_thin_module(
     // into that context. One day, however, we may do this for upstream
     // crates but for locally codegened modules we may be able to reuse
     // that LLVM Context and Module.
-    let module_llvm = ModuleLlvm::parse(cgcx, module_name, thin_module.data(), dcx)?;
+    let module_llvm = ModuleLlvm::parse(cgcx, module_name, thin_module.data(), dcx);
     let mut module = ModuleCodegen::new_regular(thin_module.name(), module_llvm);
     // Given that the newly created module lacks a thinlto buffer for embedding, we need to re-add it here.
     if cgcx.config(ModuleKind::Regular).embed_bitcode() {
@@ -746,7 +744,7 @@ pub(crate) fn optimize_thin_module(
                 .generic_activity_with_arg("LLVM_thin_lto_resolve_weak", thin_module.name());
             if unsafe { !llvm::LLVMRustPrepareThinLTOResolveWeak(thin_module.shared.data.0, llmod) }
             {
-                return Err(write::llvm_err(dcx, LlvmError::PrepareThinLtoModule));
+                write::llvm_err(dcx, LlvmError::PrepareThinLtoModule);
             }
             save_temp_bitcode(cgcx, &module, "thin-lto-after-resolve");
         }
@@ -757,7 +755,7 @@ pub(crate) fn optimize_thin_module(
                 .generic_activity_with_arg("LLVM_thin_lto_internalize", thin_module.name());
             if unsafe { !llvm::LLVMRustPrepareThinLTOInternalize(thin_module.shared.data.0, llmod) }
             {
-                return Err(write::llvm_err(dcx, LlvmError::PrepareThinLtoModule));
+                write::llvm_err(dcx, LlvmError::PrepareThinLtoModule);
             }
             save_temp_bitcode(cgcx, &module, "thin-lto-after-internalize");
         }
@@ -768,7 +766,7 @@ pub(crate) fn optimize_thin_module(
             if unsafe {
                 !llvm::LLVMRustPrepareThinLTOImport(thin_module.shared.data.0, llmod, target.raw())
             } {
-                return Err(write::llvm_err(dcx, LlvmError::PrepareThinLtoModule));
+                write::llvm_err(dcx, LlvmError::PrepareThinLtoModule);
             }
             save_temp_bitcode(cgcx, &module, "thin-lto-after-import");
         }
@@ -780,11 +778,11 @@ pub(crate) fn optimize_thin_module(
         // little differently.
         {
             info!("running thin lto passes over {}", module.name);
-            run_pass_manager(cgcx, dcx, &mut module, true)?;
+            run_pass_manager(cgcx, dcx, &mut module, true);
             save_temp_bitcode(cgcx, &module, "thin-lto-after-pm");
         }
     }
-    Ok(module)
+    module
 }
 
 /// Maps LLVM module identifiers to their corresponding LLVM LTO cache keys
@@ -850,9 +848,9 @@ pub(crate) fn parse_module<'a>(
     name: &CStr,
     data: &[u8],
     dcx: DiagCtxtHandle<'_>,
-) -> Result<&'a llvm::Module, FatalError> {
+) -> &'a llvm::Module {
     unsafe {
         llvm::LLVMRustParseBitcodeForLTO(cx, data.as_ptr(), data.len(), name.as_ptr())
-            .ok_or_else(|| write::llvm_err(dcx, LlvmError::ParseBitcode))
+            .unwrap_or_else(|| write::llvm_err(dcx, LlvmError::ParseBitcode))
     }
 }
diff --git a/compiler/rustc_codegen_llvm/src/back/write.rs b/compiler/rustc_codegen_llvm/src/back/write.rs
index 7c65d667bda88..7ea2ae6673b0f 100644
--- a/compiler/rustc_codegen_llvm/src/back/write.rs
+++ b/compiler/rustc_codegen_llvm/src/back/write.rs
@@ -20,7 +20,7 @@ use rustc_codegen_ssa::traits::*;
 use rustc_codegen_ssa::{CompiledModule, ModuleCodegen, ModuleKind};
 use rustc_data_structures::profiling::SelfProfilerRef;
 use rustc_data_structures::small_c_str::SmallCStr;
-use rustc_errors::{DiagCtxtHandle, FatalError, Level};
+use rustc_errors::{DiagCtxtHandle, Level};
 use rustc_fs_util::{link_or_copy, path_to_c_string};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
@@ -46,10 +46,10 @@ use crate::llvm::{self, DiagnosticInfo};
 use crate::type_::Type;
 use crate::{LlvmCodegenBackend, ModuleLlvm, base, common, llvm_util};
 
-pub(crate) fn llvm_err<'a>(dcx: DiagCtxtHandle<'_>, err: LlvmError<'a>) -> FatalError {
+pub(crate) fn llvm_err<'a>(dcx: DiagCtxtHandle<'_>, err: LlvmError<'a>) -> ! {
     match llvm::last_error() {
-        Some(llvm_err) => dcx.emit_almost_fatal(WithLlvmError(err, llvm_err)),
-        None => dcx.emit_almost_fatal(err),
+        Some(llvm_err) => dcx.emit_fatal(WithLlvmError(err, llvm_err)),
+        None => dcx.emit_fatal(err),
     }
 }
 
@@ -63,7 +63,7 @@ fn write_output_file<'ll>(
     file_type: llvm::FileType,
     self_profiler_ref: &SelfProfilerRef,
     verify_llvm_ir: bool,
-) -> Result<(), FatalError> {
+) {
     debug!("write_output_file output={:?} dwo_output={:?}", output, dwo_output);
     let output_c = path_to_c_string(output);
     let dwo_output_c;
@@ -100,7 +100,7 @@ fn write_output_file<'ll>(
         }
     }
 
-    result.into_result().map_err(|()| llvm_err(dcx, LlvmError::WriteOutput { path: output }))
+    result.into_result().unwrap_or_else(|()| llvm_err(dcx, LlvmError::WriteOutput { path: output }))
 }
 
 pub(crate) fn create_informational_target_machine(
@@ -112,7 +112,7 @@ pub(crate) fn create_informational_target_machine(
     // system/tcx is set up.
     let features = llvm_util::global_llvm_features(sess, false, only_base_features);
     target_machine_factory(sess, config::OptLevel::No, &features)(config)
-        .unwrap_or_else(|err| llvm_err(sess.dcx(), err).raise())
+        .unwrap_or_else(|err| llvm_err(sess.dcx(), err))
 }
 
 pub(crate) fn create_target_machine(tcx: TyCtxt<'_>, mod_name: &str) -> OwnedTargetMachine {
@@ -139,7 +139,7 @@ pub(crate) fn create_target_machine(tcx: TyCtxt<'_>, mod_name: &str) -> OwnedTar
         tcx.backend_optimization_level(()),
         tcx.global_backend_features(()),
     )(config)
-    .unwrap_or_else(|err| llvm_err(tcx.dcx(), err).raise())
+    .unwrap_or_else(|err| llvm_err(tcx.dcx(), err))
 }
 
 fn to_llvm_opt_settings(cfg: config::OptLevel) -> (llvm::CodeGenOptLevel, llvm::CodeGenOptSize) {
@@ -565,7 +565,7 @@ pub(crate) unsafe fn llvm_optimize(
     opt_level: config::OptLevel,
     opt_stage: llvm::OptStage,
     autodiff_stage: AutodiffStage,
-) -> Result<(), FatalError> {
+) {
     // Enzyme:
     // The whole point of compiler based AD is to differentiate optimized IR instead of unoptimized
     // source code. However, benchmarks show that optimizations increasing the code size
@@ -704,7 +704,7 @@ pub(crate) unsafe fn llvm_optimize(
             llvm_plugins.len(),
         )
     };
-    result.into_result().map_err(|()| llvm_err(dcx, LlvmError::RunLlvmPasses))
+    result.into_result().unwrap_or_else(|()| llvm_err(dcx, LlvmError::RunLlvmPasses))
 }
 
 // Unsafe due to LLVM calls.
@@ -713,7 +713,7 @@ pub(crate) fn optimize(
     dcx: DiagCtxtHandle<'_>,
     module: &mut ModuleCodegen<ModuleLlvm>,
     config: &ModuleConfig,
-) -> Result<(), FatalError> {
+) {
     let _timer = cgcx.prof.generic_activity_with_arg("LLVM_module_optimize", &*module.name);
 
     let llcx = &*module.module_llvm.llcx;
@@ -765,7 +765,7 @@ pub(crate) fn optimize(
                 opt_stage,
                 autodiff_stage,
             )
-        }?;
+        };
         if let Some(thin_lto_buffer) = thin_lto_buffer {
             let thin_lto_buffer = unsafe { ThinBuffer::from_raw_ptr(thin_lto_buffer) };
             module.thin_lto_buffer = Some(thin_lto_buffer.data().to_vec());
@@ -793,14 +793,13 @@ pub(crate) fn optimize(
             }
         }
     }
-    Ok(())
 }
 
 pub(crate) fn codegen(
     cgcx: &CodegenContext<LlvmCodegenBackend>,
     module: ModuleCodegen<ModuleLlvm>,
     config: &ModuleConfig,
-) -> Result<CompiledModule, FatalError> {
+) -> CompiledModule {
     let dcx = cgcx.create_dcx();
     let dcx = dcx.handle();
 
@@ -909,7 +908,9 @@ pub(crate) fn codegen(
                 record_artifact_size(&cgcx.prof, "llvm_ir", &out);
             }
 
-            result.into_result().map_err(|()| llvm_err(dcx, LlvmError::WriteIr { path: &out }))?;
+            result
+                .into_result()
+                .unwrap_or_else(|()| llvm_err(dcx, LlvmError::WriteIr { path: &out }));
         }
 
         if config.emit_asm {
@@ -940,7 +941,7 @@ pub(crate) fn codegen(
                 llvm::FileType::AssemblyFile,
                 &cgcx.prof,
                 config.verify_llvm_ir,
-            )?;
+            );
         }
 
         match config.emit_obj {
@@ -976,7 +977,7 @@ pub(crate) fn codegen(
                     llvm::FileType::ObjectFile,
                     &cgcx.prof,
                     config.verify_llvm_ir,
-                )?;
+                );
             }
 
             EmitObj::Bitcode => {
@@ -1009,7 +1010,7 @@ pub(crate) fn codegen(
         && cgcx.target_can_use_split_dwarf
         && cgcx.split_debuginfo != SplitDebuginfo::Off
         && cgcx.split_dwarf_kind == SplitDwarfKind::Split;
-    Ok(module.into_compiled_module(
+    module.into_compiled_module(
         config.emit_obj != EmitObj::None,
         dwarf_object_emitted,
         config.emit_bc,
@@ -1017,7 +1018,7 @@ pub(crate) fn codegen(
         config.emit_ir,
         &cgcx.output_filenames,
         cgcx.invocation_temp.as_deref(),
-    ))
+    )
 }
 
 fn create_section_with_flags_asm(section_name: &str, section_flags: &str, data: &[u8]) -> Vec<u8> {
diff --git a/compiler/rustc_codegen_llvm/src/lib.rs b/compiler/rustc_codegen_llvm/src/lib.rs
index 0fcf31d799308..628cb34fd9e46 100644
--- a/compiler/rustc_codegen_llvm/src/lib.rs
+++ b/compiler/rustc_codegen_llvm/src/lib.rs
@@ -37,7 +37,7 @@ use rustc_codegen_ssa::back::write::{
 use rustc_codegen_ssa::traits::*;
 use rustc_codegen_ssa::{CodegenResults, CompiledModule, ModuleCodegen, TargetConfig};
 use rustc_data_structures::fx::FxIndexMap;
-use rustc_errors::{DiagCtxtHandle, FatalError};
+use rustc_errors::DiagCtxtHandle;
 use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_middle::ty::TyCtxt;
@@ -165,15 +165,15 @@ impl WriteBackendMethods for LlvmCodegenBackend {
         exported_symbols_for_lto: &[String],
         each_linked_rlib_for_lto: &[PathBuf],
         modules: Vec<FatLtoInput<Self>>,
-    ) -> Result<ModuleCodegen<Self::Module>, FatalError> {
+    ) -> ModuleCodegen<Self::Module> {
         let mut module =
-            back::lto::run_fat(cgcx, exported_symbols_for_lto, each_linked_rlib_for_lto, modules)?;
+            back::lto::run_fat(cgcx, exported_symbols_for_lto, each_linked_rlib_for_lto, modules);
 
         let dcx = cgcx.create_dcx();
         let dcx = dcx.handle();
-        back::lto::run_pass_manager(cgcx, dcx, &mut module, false)?;
+        back::lto::run_pass_manager(cgcx, dcx, &mut module, false);
 
-        Ok(module)
+        module
     }
     fn run_thin_lto(
         cgcx: &CodegenContext<Self>,
@@ -181,7 +181,7 @@ impl WriteBackendMethods for LlvmCodegenBackend {
         each_linked_rlib_for_lto: &[PathBuf],
         modules: Vec<(String, Self::ThinBuffer)>,
         cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>,
-    ) -> Result<(Vec<ThinModule<Self>>, Vec<WorkProduct>), FatalError> {
+    ) -> (Vec<ThinModule<Self>>, Vec<WorkProduct>) {
         back::lto::run_thin(
             cgcx,
             exported_symbols_for_lto,
@@ -195,20 +195,20 @@ impl WriteBackendMethods for LlvmCodegenBackend {
         dcx: DiagCtxtHandle<'_>,
         module: &mut ModuleCodegen<Self::Module>,
         config: &ModuleConfig,
-    ) -> Result<(), FatalError> {
+    ) {
         back::write::optimize(cgcx, dcx, module, config)
     }
     fn optimize_thin(
         cgcx: &CodegenContext<Self>,
         thin: ThinModule<Self>,
-    ) -> Result<ModuleCodegen<Self::Module>, FatalError> {
+    ) -> ModuleCodegen<Self::Module> {
         back::lto::optimize_thin_module(thin, cgcx)
     }
     fn codegen(
         cgcx: &CodegenContext<Self>,
         module: ModuleCodegen<Self::Module>,
         config: &ModuleConfig,
-    ) -> Result<CompiledModule, FatalError> {
+    ) -> CompiledModule {
         back::write::codegen(cgcx, module, config)
     }
     fn prepare_thin(
@@ -407,12 +407,12 @@ impl ModuleLlvm {
         cgcx: &CodegenContext<LlvmCodegenBackend>,
         name: &str,
         dcx: DiagCtxtHandle<'_>,
-    ) -> Result<OwnedTargetMachine, FatalError> {
+    ) -> OwnedTargetMachine {
         let tm_factory_config = TargetMachineFactoryConfig::new(cgcx, name);
         match (cgcx.tm_factory)(tm_factory_config) {
-            Ok(m) => Ok(m),
+            Ok(m) => m,
             Err(e) => {
-                return Err(dcx.emit_almost_fatal(ParseTargetMachineConfig(e)));
+                dcx.emit_fatal(ParseTargetMachineConfig(e));
             }
         }
     }
@@ -422,13 +422,13 @@ impl ModuleLlvm {
         name: &CStr,
         buffer: &[u8],
         dcx: DiagCtxtHandle<'_>,
-    ) -> Result<Self, FatalError> {
+    ) -> Self {
         unsafe {
             let llcx = llvm::LLVMRustContextCreate(cgcx.fewer_names);
-            let llmod_raw = back::lto::parse_module(llcx, name, buffer, dcx)?;
-            let tm = ModuleLlvm::tm_from_cgcx(cgcx, name.to_str().unwrap(), dcx)?;
+            let llmod_raw = back::lto::parse_module(llcx, name, buffer, dcx);
+            let tm = ModuleLlvm::tm_from_cgcx(cgcx, name.to_str().unwrap(), dcx);
 
-            Ok(ModuleLlvm { llmod_raw, llcx, tm: ManuallyDrop::new(tm) })
+            ModuleLlvm { llmod_raw, llcx, tm: ManuallyDrop::new(tm) }
         }
     }
 
diff --git a/compiler/rustc_codegen_ssa/src/back/apple.rs b/compiler/rustc_codegen_ssa/src/back/apple.rs
index 2274450e20e01..b1d646d9265ff 100644
--- a/compiler/rustc_codegen_ssa/src/back/apple.rs
+++ b/compiler/rustc_codegen_ssa/src/back/apple.rs
@@ -164,7 +164,7 @@ pub(super) fn get_sdk_root(sess: &Session) -> Option<PathBuf> {
     //
     // Note that when cross-compiling from e.g. Linux, the `xcrun` binary may sometimes be provided
     // as a shim by a cross-compilation helper tool. It usually isn't, but we still try nonetheless.
-    match xcrun_show_sdk_path(sdk_name, sess.verbose_internals()) {
+    match xcrun_show_sdk_path(sdk_name, false) {
         Ok((path, stderr)) => {
             // Emit extra stderr, such as if `-verbose` was passed, or if `xcrun` emitted a warning.
             if !stderr.is_empty() {
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs
index 26d089a117108..9f22859ba81ca 100644
--- a/compiler/rustc_codegen_ssa/src/back/write.rs
+++ b/compiler/rustc_codegen_ssa/src/back/write.rs
@@ -1,5 +1,6 @@
 use std::assert_matches::assert_matches;
 use std::marker::PhantomData;
+use std::panic::AssertUnwindSafe;
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
 use std::sync::mpsc::{Receiver, Sender, channel};
@@ -14,7 +15,7 @@ use rustc_data_structures::profiling::{SelfProfilerRef, VerboseTimingGuard};
 use rustc_errors::emitter::Emitter;
 use rustc_errors::translation::Translator;
 use rustc_errors::{
-    Diag, DiagArgMap, DiagCtxt, DiagMessage, ErrCode, FatalError, Level, MultiSpan, Style,
+    Diag, DiagArgMap, DiagCtxt, DiagMessage, ErrCode, FatalErrorMarker, Level, MultiSpan, Style,
     Suggestions,
 };
 use rustc_fs_util::link_or_copy;
@@ -395,8 +396,7 @@ fn generate_thin_lto_work<B: ExtraBackendMethods>(
         each_linked_rlib_for_lto,
         needs_thin_lto,
         import_only_modules,
-    )
-    .unwrap_or_else(|e| e.raise());
+    );
     lto_modules
         .into_iter()
         .map(|module| {
@@ -844,11 +844,11 @@ fn execute_optimize_work_item<B: ExtraBackendMethods>(
     cgcx: &CodegenContext<B>,
     mut module: ModuleCodegen<B::Module>,
     module_config: &ModuleConfig,
-) -> Result<WorkItemResult<B>, FatalError> {
+) -> WorkItemResult<B> {
     let dcx = cgcx.create_dcx();
     let dcx = dcx.handle();
 
-    B::optimize(cgcx, dcx, &mut module, module_config)?;
+    B::optimize(cgcx, dcx, &mut module, module_config);
 
     // After we've done the initial round of optimizations we need to
     // decide whether to synchronously codegen this module or ship it
@@ -868,8 +868,8 @@ fn execute_optimize_work_item<B: ExtraBackendMethods>(
 
     match lto_type {
         ComputedLtoType::No => {
-            let module = B::codegen(cgcx, module, module_config)?;
-            Ok(WorkItemResult::Finished(module))
+            let module = B::codegen(cgcx, module, module_config);
+            WorkItemResult::Finished(module)
         }
         ComputedLtoType::Thin => {
             let (name, thin_buffer) = B::prepare_thin(module, false);
@@ -878,7 +878,7 @@ fn execute_optimize_work_item<B: ExtraBackendMethods>(
                     panic!("Error writing pre-lto-bitcode file `{}`: {}", path.display(), e);
                 });
             }
-            Ok(WorkItemResult::NeedsThinLto(name, thin_buffer))
+            WorkItemResult::NeedsThinLto(name, thin_buffer)
         }
         ComputedLtoType::Fat => match bitcode {
             Some(path) => {
@@ -886,12 +886,12 @@ fn execute_optimize_work_item<B: ExtraBackendMethods>(
                 fs::write(&path, buffer.data()).unwrap_or_else(|e| {
                     panic!("Error writing pre-lto-bitcode file `{}`: {}", path.display(), e);
                 });
-                Ok(WorkItemResult::NeedsFatLto(FatLtoInput::Serialized {
+                WorkItemResult::NeedsFatLto(FatLtoInput::Serialized {
                     name,
                     buffer: SerializedModule::Local(buffer),
-                }))
+                })
             }
-            None => Ok(WorkItemResult::NeedsFatLto(FatLtoInput::InMemory(module))),
+            None => WorkItemResult::NeedsFatLto(FatLtoInput::InMemory(module)),
         },
     }
 }
@@ -987,7 +987,7 @@ fn execute_fat_lto_work_item<B: ExtraBackendMethods>(
     mut needs_fat_lto: Vec<FatLtoInput<B>>,
     import_only_modules: Vec<(SerializedModule<B::ModuleBuffer>, WorkProduct)>,
     module_config: &ModuleConfig,
-) -> Result<WorkItemResult<B>, FatalError> {
+) -> WorkItemResult<B> {
     for (module, wp) in import_only_modules {
         needs_fat_lto.push(FatLtoInput::Serialized { name: wp.cgu_name, buffer: module })
     }
@@ -997,19 +997,19 @@ fn execute_fat_lto_work_item<B: ExtraBackendMethods>(
         exported_symbols_for_lto,
         each_linked_rlib_for_lto,
         needs_fat_lto,
-    )?;
-    let module = B::codegen(cgcx, module, module_config)?;
-    Ok(WorkItemResult::Finished(module))
+    );
+    let module = B::codegen(cgcx, module, module_config);
+    WorkItemResult::Finished(module)
 }
 
 fn execute_thin_lto_work_item<B: ExtraBackendMethods>(
     cgcx: &CodegenContext<B>,
     module: lto::ThinModule<B>,
     module_config: &ModuleConfig,
-) -> Result<WorkItemResult<B>, FatalError> {
-    let module = B::optimize_thin(cgcx, module)?;
-    let module = B::codegen(cgcx, module, module_config)?;
-    Ok(WorkItemResult::Finished(module))
+) -> WorkItemResult<B> {
+    let module = B::optimize_thin(cgcx, module);
+    let module = B::codegen(cgcx, module, module_config);
+    WorkItemResult::Finished(module)
 }
 
 /// Messages sent to the coordinator.
@@ -1722,37 +1722,10 @@ fn spawn_work<'a, B: ExtraBackendMethods>(
     let cgcx = cgcx.clone();
 
     B::spawn_named_thread(cgcx.time_trace, work.short_description(), move || {
-        // Set up a destructor which will fire off a message that we're done as
-        // we exit.
-        struct Bomb<B: ExtraBackendMethods> {
-            coordinator_send: Sender<Message<B>>,
-            result: Option<Result<WorkItemResult<B>, FatalError>>,
-        }
-        impl<B: ExtraBackendMethods> Drop for Bomb<B> {
-            fn drop(&mut self) {
-                let msg = match self.result.take() {
-                    Some(Ok(result)) => Message::WorkItem::<B> { result: Ok(result) },
-                    Some(Err(FatalError)) => {
-                        Message::WorkItem::<B> { result: Err(Some(WorkerFatalError)) }
-                    }
-                    None => Message::WorkItem::<B> { result: Err(None) },
-                };
-                drop(self.coordinator_send.send(msg));
-            }
-        }
-
-        let mut bomb = Bomb::<B> { coordinator_send, result: None };
-
-        // Execute the work itself, and if it finishes successfully then flag
-        // ourselves as a success as well.
-        //
-        // Note that we ignore any `FatalError` coming out of `execute_work_item`,
-        // as a diagnostic was already sent off to the main thread - just
-        // surface that there was an error in this worker.
-        bomb.result = {
+        let result = std::panic::catch_unwind(AssertUnwindSafe(|| {
             let module_config = cgcx.config(work.module_kind());
 
-            Some(match work {
+            match work {
                 WorkItem::Optimize(m) => {
                     let _timer =
                         cgcx.prof.generic_activity_with_arg("codegen_module_optimize", &*m.name);
@@ -1763,7 +1736,7 @@ fn spawn_work<'a, B: ExtraBackendMethods>(
                         "codegen_copy_artifacts_from_incr_cache",
                         &*m.name,
                     );
-                    Ok(execute_copy_from_cache_work_item(&cgcx, m, module_config))
+                    execute_copy_from_cache_work_item(&cgcx, m, module_config)
                 }
                 WorkItem::FatLto {
                     exported_symbols_for_lto,
@@ -1788,8 +1761,22 @@ fn spawn_work<'a, B: ExtraBackendMethods>(
                         cgcx.prof.generic_activity_with_arg("codegen_module_perform_lto", m.name());
                     execute_thin_lto_work_item(&cgcx, m, module_config)
                 }
-            })
+            }
+        }));
+
+        let msg = match result {
+            Ok(result) => Message::WorkItem::<B> { result: Ok(result) },
+
+            // We ignore any `FatalError` coming out of `execute_work_item`, as a
+            // diagnostic was already sent off to the main thread - just surface
+            // that there was an error in this worker.
+            Err(err) if err.is::<FatalErrorMarker>() => {
+                Message::WorkItem::<B> { result: Err(Some(WorkerFatalError)) }
+            }
+
+            Err(_) => Message::WorkItem::<B> { result: Err(None) },
         };
+        drop(coordinator_send.send(msg));
     })
     .expect("failed to spawn work thread");
 }
diff --git a/compiler/rustc_codegen_ssa/src/traits/write.rs b/compiler/rustc_codegen_ssa/src/traits/write.rs
index c29ad90735b7b..cc7c4e46d7bba 100644
--- a/compiler/rustc_codegen_ssa/src/traits/write.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/write.rs
@@ -1,6 +1,6 @@
 use std::path::PathBuf;
 
-use rustc_errors::{DiagCtxtHandle, FatalError};
+use rustc_errors::DiagCtxtHandle;
 use rustc_middle::dep_graph::WorkProduct;
 
 use crate::back::lto::{SerializedModule, ThinModule};
@@ -22,7 +22,7 @@ pub trait WriteBackendMethods: Clone + 'static {
         exported_symbols_for_lto: &[String],
         each_linked_rlib_for_lto: &[PathBuf],
         modules: Vec<FatLtoInput<Self>>,
-    ) -> Result<ModuleCodegen<Self::Module>, FatalError>;
+    ) -> ModuleCodegen<Self::Module>;
     /// Performs thin LTO by performing necessary global analysis and returning two
     /// lists, one of the modules that need optimization and another for modules that
     /// can simply be copied over from the incr. comp. cache.
@@ -32,7 +32,7 @@ pub trait WriteBackendMethods: Clone + 'static {
         each_linked_rlib_for_lto: &[PathBuf],
         modules: Vec<(String, Self::ThinBuffer)>,
         cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>,
-    ) -> Result<(Vec<ThinModule<Self>>, Vec<WorkProduct>), FatalError>;
+    ) -> (Vec<ThinModule<Self>>, Vec<WorkProduct>);
     fn print_pass_timings(&self);
     fn print_statistics(&self);
     fn optimize(
@@ -40,16 +40,16 @@ pub trait WriteBackendMethods: Clone + 'static {
         dcx: DiagCtxtHandle<'_>,
         module: &mut ModuleCodegen<Self::Module>,
         config: &ModuleConfig,
-    ) -> Result<(), FatalError>;
+    );
     fn optimize_thin(
         cgcx: &CodegenContext<Self>,
         thin: ThinModule<Self>,
-    ) -> Result<ModuleCodegen<Self::Module>, FatalError>;
+    ) -> ModuleCodegen<Self::Module>;
     fn codegen(
         cgcx: &CodegenContext<Self>,
         module: ModuleCodegen<Self::Module>,
         config: &ModuleConfig,
-    ) -> Result<CompiledModule, FatalError>;
+    ) -> CompiledModule;
     fn prepare_thin(
         module: ModuleCodegen<Self::Module>,
         want_summary: bool,
diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs
index da954cf4ed740..fccb6b171b1c2 100644
--- a/compiler/rustc_const_eval/src/const_eval/machine.rs
+++ b/compiler/rustc_const_eval/src/const_eval/machine.rs
@@ -280,22 +280,110 @@ impl<'tcx> CompileTimeInterpCx<'tcx> {
         interp_ok(match (a, b) {
             // Comparisons between integers are always known.
             (Scalar::Int(a), Scalar::Int(b)) => (a == b) as u8,
-            // Comparisons of null with an arbitrary scalar can be known if `scalar_may_be_null`
-            // indicates that the scalar can definitely *not* be null.
-            (Scalar::Int(int), ptr) | (ptr, Scalar::Int(int))
-                if int.is_null() && !self.scalar_may_be_null(ptr)? =>
-            {
-                0
+            // Comparing a pointer `ptr` with an integer `int` is equivalent to comparing
+            // `ptr-int` with null, so we can reduce this case to a `scalar_may_be_null` test.
+            (Scalar::Int(int), Scalar::Ptr(ptr, _)) | (Scalar::Ptr(ptr, _), Scalar::Int(int)) => {
+                let int = int.to_target_usize(*self.tcx);
+                // The `wrapping_neg` here may produce a value that is not
+                // a valid target usize any more... but `wrapping_offset` handles that correctly.
+                let offset_ptr = ptr.wrapping_offset(Size::from_bytes(int.wrapping_neg()), self);
+                if !self.scalar_may_be_null(Scalar::from_pointer(offset_ptr, self))? {
+                    // `ptr.wrapping_sub(int)` is definitely not equal to `0`, so `ptr != int`
+                    0
+                } else {
+                    // `ptr.wrapping_sub(int)` could be equal to `0`, but might not be,
+                    // so we cannot know for sure if `ptr == int` or not
+                    2
+                }
+            }
+            (Scalar::Ptr(a, _), Scalar::Ptr(b, _)) => {
+                let (a_prov, a_offset) = a.prov_and_relative_offset();
+                let (b_prov, b_offset) = b.prov_and_relative_offset();
+                let a_allocid = a_prov.alloc_id();
+                let b_allocid = b_prov.alloc_id();
+                let a_info = self.get_alloc_info(a_allocid);
+                let b_info = self.get_alloc_info(b_allocid);
+
+                // Check if the pointers cannot be equal due to alignment
+                if a_info.align > Align::ONE && b_info.align > Align::ONE {
+                    let min_align = Ord::min(a_info.align.bytes(), b_info.align.bytes());
+                    let a_residue = a_offset.bytes() % min_align;
+                    let b_residue = b_offset.bytes() % min_align;
+                    if a_residue != b_residue {
+                        // If the two pointers have a different residue modulo their
+                        // common alignment, they cannot be equal.
+                        return interp_ok(0);
+                    }
+                    // The pointers have the same residue modulo their common alignment,
+                    // so they could be equal. Try the other checks.
+                }
+
+                if let (Some(GlobalAlloc::Static(a_did)), Some(GlobalAlloc::Static(b_did))) = (
+                    self.tcx.try_get_global_alloc(a_allocid),
+                    self.tcx.try_get_global_alloc(b_allocid),
+                ) {
+                    if a_allocid == b_allocid {
+                        debug_assert_eq!(
+                            a_did, b_did,
+                            "different static item DefIds had same AllocId? {a_allocid:?} == {b_allocid:?}, {a_did:?} != {b_did:?}"
+                        );
+                        // Comparing two pointers into the same static. As per
+                        // https://doc.rust-lang.org/nightly/reference/items/static-items.html#r-items.static.intro
+                        // a static cannot be duplicated, so if two pointers are into the same
+                        // static, they are equal if and only if their offsets are equal.
+                        (a_offset == b_offset) as u8
+                    } else {
+                        debug_assert_ne!(
+                            a_did, b_did,
+                            "same static item DefId had two different AllocIds? {a_allocid:?} != {b_allocid:?}, {a_did:?} == {b_did:?}"
+                        );
+                        // Comparing two pointers into the different statics.
+                        // We can never determine for sure that two pointers into different statics
+                        // are *equal*, but we can know that they are *inequal* if they are both
+                        // strictly in-bounds (i.e. in-bounds and not one-past-the-end) of
+                        // their respective static, as different non-zero-sized statics cannot
+                        // overlap or be deduplicated as per
+                        // https://doc.rust-lang.org/nightly/reference/items/static-items.html#r-items.static.intro
+                        // (non-deduplication), and
+                        // https://doc.rust-lang.org/nightly/reference/items/static-items.html#r-items.static.storage-disjointness
+                        // (non-overlapping).
+                        if a_offset < a_info.size && b_offset < b_info.size {
+                            0
+                        } else {
+                            // Otherwise, conservatively say we don't know.
+                            // There are some cases we could still return `0` for, e.g.
+                            // if the pointers being equal would require their statics to overlap
+                            // one or more bytes, but for simplicity we currently only check
+                            // strictly in-bounds pointers.
+                            2
+                        }
+                    }
+                } else {
+                    // All other cases we conservatively say we don't know.
+                    //
+                    // For comparing statics to non-statics, as per https://doc.rust-lang.org/nightly/reference/items/static-items.html#r-items.static.storage-disjointness
+                    // immutable statics can overlap with other kinds of allocations sometimes.
+                    //
+                    // FIXME: We could be more decisive for (non-zero-sized) mutable statics,
+                    // which cannot overlap with other kinds of allocations.
+                    //
+                    // Functions and vtables can be duplicated and deduplicated, so we
+                    // cannot be sure of runtime equality of pointers to the same one, or the
+                    // runtime inequality of pointers to different ones (see e.g. #73722),
+                    // so comparing those should return 2, whether they are the same allocation
+                    // or not.
+                    //
+                    // `GlobalAlloc::TypeId` exists mostly to prevent consteval from comparing
+                    // `TypeId`s, so comparing those should always return 2, whether they are the
+                    // same allocation or not.
+                    //
+                    // FIXME: We could revisit comparing pointers into the same
+                    // `GlobalAlloc::Memory` once https://github.com/rust-lang/rust/issues/128775
+                    // is fixed (but they can be deduplicated, so comparing pointers into different
+                    // ones should return 2).
+                    2
+                }
             }
-            // Other ways of comparing integers and pointers can never be known for sure.
-            (Scalar::Int { .. }, Scalar::Ptr(..)) | (Scalar::Ptr(..), Scalar::Int { .. }) => 2,
-            // FIXME: return a `1` for when both sides are the same pointer, *except* that
-            // some things (like functions and vtables) do not have stable addresses
-            // so we need to be careful around them (see e.g. #73722).
-            // FIXME: return `0` for at least some comparisons where we can reliably
-            // determine the result of runtime inequality tests at compile-time.
-            // Examples include comparison of addresses in different static items.
-            (Scalar::Ptr(..), Scalar::Ptr(..)) => 2,
         })
     }
 }
diff --git a/library/compiler-builtins/compiler-builtins/README.md b/library/compiler-builtins/compiler-builtins/README.md
index 387b70c0499a6..2d92b7651f980 100644
--- a/library/compiler-builtins/compiler-builtins/README.md
+++ b/library/compiler-builtins/compiler-builtins/README.md
@@ -10,6 +10,16 @@ to be added as an explicit dependency in `Cargo.toml`.
 
 [`compiler-rt`]: https://github.com/llvm/llvm-project/tree/1b1dc505057322f4fa1110ef4f53c44347f52986/compiler-rt
 
+## Configuration
+
+`compiler-builtins` can be configured with the following environment variables when the `c` feature
+is enabled:
+
+- `LLVM_COMPILER_RT_LIB`
+- `RUST_COMPILER_RT_ROOT`
+
+See `build.rs` for details.
+
 ## Contributing
 
 See [CONTRIBUTING.md](CONTRIBUTING.md).
diff --git a/library/compiler-builtins/compiler-builtins/build.rs b/library/compiler-builtins/compiler-builtins/build.rs
index 43b978606e5f0..6e1d230e3cd26 100644
--- a/library/compiler-builtins/compiler-builtins/build.rs
+++ b/library/compiler-builtins/compiler-builtins/build.rs
@@ -540,12 +540,20 @@ mod c {
             sources.extend(&[("__emutls_get_address", "emutls.c")]);
         }
 
+        // Optionally, link against a prebuilt llvm compiler-rt containing the builtins
+        // library. Only the builtins library is required. On many platforms, this is
+        // available as a library named libclang_rt.builtins.a.
+        let link_against_prebuilt_rt = env::var_os("LLVM_COMPILER_RT_LIB").is_some();
+
         // When compiling the C code we require the user to tell us where the
         // source code is, and this is largely done so when we're compiling as
         // part of rust-lang/rust we can use the same llvm-project repository as
         // rust-lang/rust.
         let root = match env::var_os("RUST_COMPILER_RT_ROOT") {
             Some(s) => PathBuf::from(s),
+            // If a prebuild libcompiler-rt is provided, set a valid
+            // path to simplify later logic. Nothing should be compiled.
+            None if link_against_prebuilt_rt => PathBuf::new(),
             None => {
                 panic!(
                     "RUST_COMPILER_RT_ROOT is not set. You may need to run \
@@ -553,7 +561,7 @@ mod c {
                 );
             }
         };
-        if !root.exists() {
+        if !link_against_prebuilt_rt && !root.exists() {
             panic!("RUST_COMPILER_RT_ROOT={} does not exist", root.display());
         }
 
@@ -569,7 +577,7 @@ mod c {
         let src_dir = root.join("lib/builtins");
         if target.arch == "aarch64" && target.env != "msvc" && target.os != "uefi" {
             // See below for why we're building these as separate libraries.
-            build_aarch64_out_of_line_atomics_libraries(&src_dir, cfg);
+            build_aarch64_out_of_line_atomics_libraries(&src_dir, cfg, link_against_prebuilt_rt);
 
             // Some run-time CPU feature detection is necessary, as well.
             let cpu_model_src = if src_dir.join("cpu_model.c").exists() {
@@ -583,20 +591,45 @@ mod c {
         let mut added_sources = HashSet::new();
         for (sym, src) in sources.map.iter() {
             let src = src_dir.join(src);
-            if added_sources.insert(src.clone()) {
+            if !link_against_prebuilt_rt && added_sources.insert(src.clone()) {
                 cfg.file(&src);
                 println!("cargo:rerun-if-changed={}", src.display());
             }
             println!("cargo:rustc-cfg={}=\"optimized-c\"", sym);
         }
 
-        cfg.compile("libcompiler-rt.a");
+        if link_against_prebuilt_rt {
+            let rt_builtins_ext = PathBuf::from(env::var_os("LLVM_COMPILER_RT_LIB").unwrap());
+            if !rt_builtins_ext.exists() {
+                panic!(
+                    "LLVM_COMPILER_RT_LIB={} does not exist",
+                    rt_builtins_ext.display()
+                );
+            }
+            if let Some(dir) = rt_builtins_ext.parent() {
+                println!("cargo::rustc-link-search=native={}", dir.display());
+            }
+            if let Some(lib) = rt_builtins_ext.file_name() {
+                println!(
+                    "cargo::rustc-link-lib=static:+verbatim={}",
+                    lib.to_str().unwrap()
+                );
+            }
+        } else {
+            cfg.compile("libcompiler-rt.a");
+        }
     }
 
-    fn build_aarch64_out_of_line_atomics_libraries(builtins_dir: &Path, cfg: &mut cc::Build) {
+    fn build_aarch64_out_of_line_atomics_libraries(
+        builtins_dir: &Path,
+        cfg: &mut cc::Build,
+        link_against_prebuilt_rt: bool,
+    ) {
         let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
         let outlined_atomics_file = builtins_dir.join("aarch64").join("lse.S");
-        println!("cargo:rerun-if-changed={}", outlined_atomics_file.display());
+        if !link_against_prebuilt_rt {
+            println!("cargo:rerun-if-changed={}", outlined_atomics_file.display());
+        }
 
         cfg.include(&builtins_dir);
 
@@ -609,6 +642,13 @@ mod c {
                 for (model_number, model_name) in
                     &[(1, "relax"), (2, "acq"), (3, "rel"), (4, "acq_rel")]
                 {
+                    let sym = format!("__aarch64_{}{}_{}", instruction_type, size, model_name);
+                    println!("cargo:rustc-cfg={}=\"optimized-c\"", sym);
+
+                    if link_against_prebuilt_rt {
+                        continue;
+                    }
+
                     // The original compiler-rt build system compiles the same
                     // source file multiple times with different compiler
                     // options. Here we do something slightly different: we
@@ -632,9 +672,6 @@ mod c {
                     .unwrap();
                     drop(file);
                     cfg.file(path);
-
-                    let sym = format!("__aarch64_{}{}_{}", instruction_type, size, model_name);
-                    println!("cargo:rustc-cfg={}=\"optimized-c\"", sym);
                 }
             }
         }
diff --git a/src/bootstrap/src/core/build_steps/compile.rs b/src/bootstrap/src/core/build_steps/compile.rs
index 8cad5b920b913..f7a2dc1421848 100644
--- a/src/bootstrap/src/core/build_steps/compile.rs
+++ b/src/bootstrap/src/core/build_steps/compile.rs
@@ -26,7 +26,9 @@ use crate::core::builder;
 use crate::core::builder::{
     Builder, Cargo, Kind, RunConfig, ShouldRun, Step, StepMetadata, crate_description,
 };
-use crate::core::config::{DebuginfoLevel, LlvmLibunwind, RustcLto, TargetSelection};
+use crate::core::config::{
+    CompilerBuiltins, DebuginfoLevel, LlvmLibunwind, RustcLto, TargetSelection,
+};
 use crate::utils::build_stamp;
 use crate::utils::build_stamp::BuildStamp;
 use crate::utils::exec::command;
@@ -574,29 +576,36 @@ pub fn std_cargo(builder: &Builder<'_>, target: TargetSelection, cargo: &mut Car
     // If `compiler-rt` is available ensure that the `c` feature of the
     // `compiler-builtins` crate is enabled and it's configured to learn where
     // `compiler-rt` is located.
-    let compiler_builtins_c_feature = if builder.config.optimized_compiler_builtins(target) {
-        // NOTE: this interacts strangely with `llvm-has-rust-patches`. In that case, we enforce `submodules = false`, so this is a no-op.
-        // But, the user could still decide to manually use an in-tree submodule.
-        //
-        // NOTE: if we're using system llvm, we'll end up building a version of `compiler-rt` that doesn't match the LLVM we're linking to.
-        // That's probably ok? At least, the difference wasn't enforced before. There's a comment in
-        // the compiler_builtins build script that makes me nervous, though:
-        // https://github.com/rust-lang/compiler-builtins/blob/31ee4544dbe47903ce771270d6e3bea8654e9e50/build.rs#L575-L579
-        builder.require_submodule(
-            "src/llvm-project",
-            Some(
-                "The `build.optimized-compiler-builtins` config option \
-                 requires `compiler-rt` sources from LLVM.",
-            ),
-        );
-        let compiler_builtins_root = builder.src.join("src/llvm-project/compiler-rt");
-        assert!(compiler_builtins_root.exists());
-        // The path to `compiler-rt` is also used by `profiler_builtins` (above),
-        // so if you're changing something here please also change that as appropriate.
-        cargo.env("RUST_COMPILER_RT_ROOT", &compiler_builtins_root);
-        " compiler-builtins-c"
-    } else {
-        ""
+    let compiler_builtins_c_feature = match builder.config.optimized_compiler_builtins(target) {
+        CompilerBuiltins::LinkLLVMBuiltinsLib(path) => {
+            cargo.env("LLVM_COMPILER_RT_LIB", path);
+            " compiler-builtins-c"
+        }
+        CompilerBuiltins::BuildLLVMFuncs => {
+            // NOTE: this interacts strangely with `llvm-has-rust-patches`. In that case, we enforce
+            // `submodules = false`, so this is a no-op. But, the user could still decide to
+            //  manually use an in-tree submodule.
+            //
+            // NOTE: if we're using system llvm, we'll end up building a version of `compiler-rt`
+            // that doesn't match the LLVM we're linking to. That's probably ok? At least, the
+            // difference wasn't enforced before. There's a comment in the compiler_builtins build
+            // script that makes me nervous, though:
+            // https://github.com/rust-lang/compiler-builtins/blob/31ee4544dbe47903ce771270d6e3bea8654e9e50/build.rs#L575-L579
+            builder.require_submodule(
+                "src/llvm-project",
+                Some(
+                    "The `build.optimized-compiler-builtins` config option \
+                     requires `compiler-rt` sources from LLVM.",
+                ),
+            );
+            let compiler_builtins_root = builder.src.join("src/llvm-project/compiler-rt");
+            assert!(compiler_builtins_root.exists());
+            // The path to `compiler-rt` is also used by `profiler_builtins` (above),
+            // so if you're changing something here please also change that as appropriate.
+            cargo.env("RUST_COMPILER_RT_ROOT", &compiler_builtins_root);
+            " compiler-builtins-c"
+        }
+        CompilerBuiltins::BuildRustOnly => "",
     };
 
     // `libtest` uses this to know whether or not to support
diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index 318287df08a2f..b52707032ba14 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -3117,45 +3117,55 @@ impl Step for Distcheck {
     ///
     /// FIXME(#136822): dist components are under-tested.
     fn run(self, builder: &Builder<'_>) {
-        builder.info("Distcheck");
-        let dir = builder.tempdir().join("distcheck");
-        let _ = fs::remove_dir_all(&dir);
-        t!(fs::create_dir_all(&dir));
-
-        // Guarantee that these are built before we begin running.
-        builder.ensure(dist::PlainSourceTarball);
-        builder.ensure(dist::Src);
+        // Use a temporary directory completely outside the current checkout, to avoid reusing any
+        // local source code, built artifacts or configuration by accident
+        let root_dir = std::env::temp_dir().join("distcheck");
+
+        // Check that we can build some basic things from the plain source tarball
+        builder.info("Distcheck plain source tarball");
+        let plain_src_tarball = builder.ensure(dist::PlainSourceTarball);
+        let plain_src_dir = root_dir.join("distcheck-plain-src");
+        builder.clear_dir(&plain_src_dir);
+
+        let configure_args: Vec<String> = std::env::var("DISTCHECK_CONFIGURE_ARGS")
+            .map(|args| args.split(" ").map(|s| s.to_string()).collect::<Vec<String>>())
+            .unwrap_or_default();
 
         command("tar")
             .arg("-xf")
-            .arg(builder.ensure(dist::PlainSourceTarball).tarball())
+            .arg(plain_src_tarball.tarball())
             .arg("--strip-components=1")
-            .current_dir(&dir)
+            .current_dir(&plain_src_dir)
             .run(builder);
         command("./configure")
-            .args(&builder.config.configure_args)
+            .arg("--set")
+            .arg("rust.omit-git-hash=false")
+            .args(&configure_args)
             .arg("--enable-vendor")
-            .current_dir(&dir)
+            .current_dir(&plain_src_dir)
             .run(builder);
         command(helpers::make(&builder.config.host_target.triple))
             .arg("check")
-            .current_dir(&dir)
+            // Do not run the build as if we were in CI, otherwise git would be assumed to be
+            // present, but we build from a tarball here
+            .env("GITHUB_ACTIONS", "0")
+            .current_dir(&plain_src_dir)
             .run(builder);
 
         // Now make sure that rust-src has all of libstd's dependencies
         builder.info("Distcheck rust-src");
-        let dir = builder.tempdir().join("distcheck-src");
-        let _ = fs::remove_dir_all(&dir);
-        t!(fs::create_dir_all(&dir));
+        let src_tarball = builder.ensure(dist::Src);
+        let src_dir = root_dir.join("distcheck-src");
+        builder.clear_dir(&src_dir);
 
         command("tar")
             .arg("-xf")
-            .arg(builder.ensure(dist::Src).tarball())
+            .arg(src_tarball.tarball())
             .arg("--strip-components=1")
-            .current_dir(&dir)
+            .current_dir(&src_dir)
             .run(builder);
 
-        let toml = dir.join("rust-src/lib/rustlib/src/rust/library/std/Cargo.toml");
+        let toml = src_dir.join("rust-src/lib/rustlib/src/rust/library/std/Cargo.toml");
         command(&builder.initial_cargo)
             // Will read the libstd Cargo.toml
             // which uses the unstable `public-dependency` feature.
@@ -3163,7 +3173,7 @@ impl Step for Distcheck {
             .arg("generate-lockfile")
             .arg("--manifest-path")
             .arg(&toml)
-            .current_dir(&dir)
+            .current_dir(&src_dir)
             .run(builder);
     }
 }
diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
index 05c2579ac0840..e5c2e3c64b803 100644
--- a/src/bootstrap/src/core/config/config.rs
+++ b/src/bootstrap/src/core/config/config.rs
@@ -46,8 +46,8 @@ use crate::core::config::toml::rust::{
 };
 use crate::core::config::toml::target::Target;
 use crate::core::config::{
-    DebuginfoLevel, DryRun, GccCiMode, LlvmLibunwind, Merge, ReplaceOpt, RustcLto, SplitDebuginfo,
-    StringOrBool, threads_from_config,
+    CompilerBuiltins, DebuginfoLevel, DryRun, GccCiMode, LlvmLibunwind, Merge, ReplaceOpt,
+    RustcLto, SplitDebuginfo, StringOrBool, threads_from_config,
 };
 use crate::core::download::{
     DownloadContext, download_beta_toolchain, is_download_ci_available, maybe_download_rustfmt,
@@ -121,8 +121,7 @@ pub struct Config {
     pub patch_binaries_for_nix: Option<bool>,
     pub stage0_metadata: build_helper::stage0_parser::Stage0,
     pub android_ndk: Option<PathBuf>,
-    /// Whether to use the `c` feature of the `compiler_builtins` crate.
-    pub optimized_compiler_builtins: bool,
+    pub optimized_compiler_builtins: CompilerBuiltins,
 
     pub stdout_is_tty: bool,
     pub stderr_is_tty: bool,
@@ -1109,7 +1108,11 @@ impl Config {
         let rustfmt_info = git_info(&exec_ctx, omit_git_hash, &src.join("src/tools/rustfmt"));
 
         let optimized_compiler_builtins =
-            build_optimized_compiler_builtins.unwrap_or(channel != "dev");
+            build_optimized_compiler_builtins.unwrap_or(if channel == "dev" {
+                CompilerBuiltins::BuildRustOnly
+            } else {
+                CompilerBuiltins::BuildLLVMFuncs
+            });
         let vendor = build_vendor.unwrap_or(
             rust_info.is_from_tarball()
                 && src.join("vendor").exists()
@@ -1672,11 +1675,11 @@ impl Config {
         self.target_config.get(&target).and_then(|t| t.rpath).unwrap_or(self.rust_rpath)
     }
 
-    pub fn optimized_compiler_builtins(&self, target: TargetSelection) -> bool {
+    pub fn optimized_compiler_builtins(&self, target: TargetSelection) -> &CompilerBuiltins {
         self.target_config
             .get(&target)
-            .and_then(|t| t.optimized_compiler_builtins)
-            .unwrap_or(self.optimized_compiler_builtins)
+            .and_then(|t| t.optimized_compiler_builtins.as_ref())
+            .unwrap_or(&self.optimized_compiler_builtins)
     }
 
     pub fn llvm_enabled(&self, target: TargetSelection) -> bool {
diff --git a/src/bootstrap/src/core/config/mod.rs b/src/bootstrap/src/core/config/mod.rs
index dbd05fd251970..5999348a7fe8d 100644
--- a/src/bootstrap/src/core/config/mod.rs
+++ b/src/bootstrap/src/core/config/mod.rs
@@ -218,6 +218,33 @@ impl<T> Merge for Option<T> {
     }
 }
 
+#[derive(Clone, Debug, Default, Eq, PartialEq)]
+pub enum CompilerBuiltins {
+    #[default]
+    // Only build native rust intrinsic compiler functions.
+    BuildRustOnly,
+    // Some intrinsic functions have a C implementation provided by LLVM's
+    // compiler-rt builtins library. Build them from the LLVM source included
+    // with Rust.
+    BuildLLVMFuncs,
+    // Similar to BuildLLVMFuncs, but specify a path to an existing library
+    // containing LLVM's compiler-rt builtins instead of compiling them.
+    LinkLLVMBuiltinsLib(String),
+}
+
+impl<'de> Deserialize<'de> for CompilerBuiltins {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        Ok(match Deserialize::deserialize(deserializer)? {
+            StringOrBool::Bool(false) => Self::BuildRustOnly,
+            StringOrBool::Bool(true) => Self::BuildLLVMFuncs,
+            StringOrBool::String(path) => Self::LinkLLVMBuiltinsLib(path),
+        })
+    }
+}
+
 #[derive(Copy, Clone, Default, Debug, Eq, PartialEq)]
 pub enum DebuginfoLevel {
     #[default]
diff --git a/src/bootstrap/src/core/config/tests.rs b/src/bootstrap/src/core/config/tests.rs
index 50eba12aba747..e93525fbd09ce 100644
--- a/src/bootstrap/src/core/config/tests.rs
+++ b/src/bootstrap/src/core/config/tests.rs
@@ -17,7 +17,7 @@ use crate::core::build_steps::clippy::{LintConfig, get_clippy_rules_in_order};
 use crate::core::build_steps::llvm;
 use crate::core::build_steps::llvm::LLVM_INVALIDATION_PATHS;
 use crate::core::config::toml::TomlConfig;
-use crate::core::config::{LldMode, Target, TargetSelection};
+use crate::core::config::{CompilerBuiltins, LldMode, StringOrBool, Target, TargetSelection};
 use crate::utils::tests::git::git_test;
 
 pub(crate) fn parse(config: &str) -> Config {
@@ -183,7 +183,11 @@ runner = "x86_64-runner"
     );
     assert_eq!(config.gdb, Some("bar".into()), "setting string value with quotes");
     assert!(!config.deny_warnings, "setting boolean value");
-    assert!(config.optimized_compiler_builtins, "setting boolean value");
+    assert_eq!(
+        config.optimized_compiler_builtins,
+        CompilerBuiltins::BuildLLVMFuncs,
+        "setting boolean value"
+    );
     assert_eq!(
         config.tools,
         Some(["cargo".to_string()].into_iter().collect()),
@@ -212,7 +216,7 @@ runner = "x86_64-runner"
     let darwin = TargetSelection::from_user("aarch64-apple-darwin");
     let darwin_values = Target {
         runner: Some("apple".into()),
-        optimized_compiler_builtins: Some(false),
+        optimized_compiler_builtins: Some(CompilerBuiltins::BuildRustOnly),
         ..Default::default()
     };
     assert_eq!(
diff --git a/src/bootstrap/src/core/config/toml/build.rs b/src/bootstrap/src/core/config/toml/build.rs
index 728367b397290..25c19f1070a39 100644
--- a/src/bootstrap/src/core/config/toml/build.rs
+++ b/src/bootstrap/src/core/config/toml/build.rs
@@ -11,7 +11,7 @@ use std::collections::HashMap;
 use serde::{Deserialize, Deserializer};
 
 use crate::core::config::toml::ReplaceOpt;
-use crate::core::config::{Merge, StringOrBool};
+use crate::core::config::{CompilerBuiltins, Merge, StringOrBool};
 use crate::{HashSet, PathBuf, define_config, exit};
 
 define_config! {
@@ -65,7 +65,7 @@ define_config! {
         // NOTE: only parsed by bootstrap.py, `--feature build-metrics` enables metrics unconditionally
         metrics: Option<bool> = "metrics",
         android_ndk: Option<PathBuf> = "android-ndk",
-        optimized_compiler_builtins: Option<bool> = "optimized-compiler-builtins",
+        optimized_compiler_builtins: Option<CompilerBuiltins> = "optimized-compiler-builtins",
         jobs: Option<u32> = "jobs",
         compiletest_diff_tool: Option<String> = "compiletest-diff-tool",
         compiletest_allow_stage0: Option<bool> = "compiletest-allow-stage0",
diff --git a/src/bootstrap/src/core/config/toml/rust.rs b/src/bootstrap/src/core/config/toml/rust.rs
index 3dab8d1d96d53..7f111094c3f1b 100644
--- a/src/bootstrap/src/core/config/toml/rust.rs
+++ b/src/bootstrap/src/core/config/toml/rust.rs
@@ -269,9 +269,9 @@ pub fn check_incompatible_options_for_ci_rustc(
     err!(current_profiler, profiler, "build");
 
     let current_optimized_compiler_builtins =
-        current_config_toml.build.as_ref().and_then(|b| b.optimized_compiler_builtins);
+        current_config_toml.build.as_ref().and_then(|b| b.optimized_compiler_builtins.clone());
     let optimized_compiler_builtins =
-        ci_config_toml.build.as_ref().and_then(|b| b.optimized_compiler_builtins);
+        ci_config_toml.build.as_ref().and_then(|b| b.optimized_compiler_builtins.clone());
     err!(current_optimized_compiler_builtins, optimized_compiler_builtins, "build");
 
     // We always build the in-tree compiler on cross targets, so we only care
diff --git a/src/bootstrap/src/core/config/toml/target.rs b/src/bootstrap/src/core/config/toml/target.rs
index 2c06fd083a810..020602e6a1997 100644
--- a/src/bootstrap/src/core/config/toml/target.rs
+++ b/src/bootstrap/src/core/config/toml/target.rs
@@ -11,7 +11,9 @@
 
 use serde::{Deserialize, Deserializer};
 
-use crate::core::config::{LlvmLibunwind, Merge, ReplaceOpt, SplitDebuginfo, StringOrBool};
+use crate::core::config::{
+    CompilerBuiltins, LlvmLibunwind, Merge, ReplaceOpt, SplitDebuginfo, StringOrBool,
+};
 use crate::{CodegenBackendKind, HashSet, PathBuf, define_config, exit};
 
 define_config! {
@@ -39,7 +41,7 @@ define_config! {
         no_std: Option<bool> = "no-std",
         codegen_backends: Option<Vec<String>> = "codegen-backends",
         runner: Option<String> = "runner",
-        optimized_compiler_builtins: Option<bool> = "optimized-compiler-builtins",
+        optimized_compiler_builtins: Option<CompilerBuiltins> = "optimized-compiler-builtins",
         jemalloc: Option<bool> = "jemalloc",
     }
 }
@@ -71,7 +73,7 @@ pub struct Target {
     pub runner: Option<String>,
     pub no_std: bool,
     pub codegen_backends: Option<Vec<CodegenBackendKind>>,
-    pub optimized_compiler_builtins: Option<bool>,
+    pub optimized_compiler_builtins: Option<CompilerBuiltins>,
     pub jemalloc: Option<bool>,
 }
 
diff --git a/src/bootstrap/src/core/sanity.rs b/src/bootstrap/src/core/sanity.rs
index de7cada93f23f..4916ebbd61098 100644
--- a/src/bootstrap/src/core/sanity.rs
+++ b/src/bootstrap/src/core/sanity.rs
@@ -18,7 +18,7 @@ use crate::builder::Builder;
 use crate::builder::Kind;
 #[cfg(not(test))]
 use crate::core::build_steps::tool;
-use crate::core::config::Target;
+use crate::core::config::{CompilerBuiltins, Target};
 use crate::utils::exec::command;
 use crate::{Build, Subcommand};
 
@@ -330,7 +330,8 @@ than building it.
 
         // compiler-rt c fallbacks for wasm cannot be built with gcc
         if target.contains("wasm")
-            && (build.config.optimized_compiler_builtins(*target)
+            && (*build.config.optimized_compiler_builtins(*target)
+                != CompilerBuiltins::BuildRustOnly
                 || build.config.rust_std_features.contains("compiler-builtins-c"))
         {
             let cc_tool = build.cc_tool(*target);
diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
index ec7edbf753129..b8ee83b20e46b 100644
--- a/src/bootstrap/src/lib.rs
+++ b/src/bootstrap/src/lib.rs
@@ -1950,6 +1950,20 @@ impl Build {
         t!(fs::remove_dir_all(dir))
     }
 
+    /// Make sure that `dir` will be an empty existing directory after this function ends.
+    /// If it existed before, it will be first deleted.
+    fn clear_dir(&self, dir: &Path) {
+        if self.config.dry_run() {
+            return;
+        }
+
+        #[cfg(feature = "tracing")]
+        let _span = trace_io!("dir-clear", ?dir);
+
+        let _ = std::fs::remove_dir_all(dir);
+        self.create_dir(dir);
+    }
+
     fn read_dir(&self, dir: &Path) -> impl Iterator<Item = fs::DirEntry> {
         let iter = match fs::read_dir(dir) {
             Ok(v) => v,
diff --git a/src/bootstrap/src/utils/change_tracker.rs b/src/bootstrap/src/utils/change_tracker.rs
index 54f563fe68c70..073954e933781 100644
--- a/src/bootstrap/src/utils/change_tracker.rs
+++ b/src/bootstrap/src/utils/change_tracker.rs
@@ -521,4 +521,9 @@ pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
         severity: ChangeSeverity::Warning,
         summary: "It is no longer possible to `x dist` or `x install` with stage 0. All dist and install commands have to be on stage 1+.",
     },
+    ChangeInfo {
+        change_id: 143689,
+        severity: ChangeSeverity::Info,
+        summary: "The `optimized-compiler-builtins` option now accepts a path to an existing compiler-rt builtins library.",
+    },
 ];
diff --git a/src/build_helper/src/npm.rs b/src/build_helper/src/npm.rs
index 86cf6183bd045..5a7df0999bd3d 100644
--- a/src/build_helper/src/npm.rs
+++ b/src/build_helper/src/npm.rs
@@ -27,7 +27,7 @@ pub fn install(src_root_path: &Path, out_dir: &Path, npm: &Path) -> Result<PathB
     }
     // disable a bunch of things we don't want.
     // this makes tidy output less noisy, and also significantly improves runtime
-    // of repeated tidy invokations.
+    // of repeated tidy invocations.
     cmd.args(&["--audit=false", "--save=false", "--fund=false"]);
     cmd.current_dir(out_dir);
     let exit_status = cmd.spawn()?.wait()?;
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-distcheck/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-distcheck/Dockerfile
index 98fd31a22e938..5bafd89cfd91d 100644
--- a/src/ci/docker/host-x86_64/x86_64-gnu-distcheck/Dockerfile
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-distcheck/Dockerfile
@@ -33,9 +33,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
-# We are disabling CI LLVM since distcheck is an offline build.
-ENV NO_DOWNLOAD_CI_LLVM 1
+# Make distcheck builds faster
+ENV DISTCHECK_CONFIGURE_ARGS "--enable-sccache"
 
-ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu --set rust.omit-git-hash=false
-ENV SCRIPT python3 ../x.py --stage 2 test distcheck
-ENV DIST_SRC 1
+ENV SCRIPT python3 ../x.py test distcheck
diff --git a/src/ci/github-actions/jobs.yml b/src/ci/github-actions/jobs.yml
index 409d2cba8210e..35b9456d37d2f 100644
--- a/src/ci/github-actions/jobs.yml
+++ b/src/ci/github-actions/jobs.yml
@@ -104,10 +104,10 @@ jobs:
 # These jobs automatically inherit envs.pr, to avoid repeating it in each job
 # definition.
 #
-# PR CI jobs will be automatically registered as Auto CI jobs or overriden. When
+# PR CI jobs will be automatically registered as Auto CI jobs or overridden. When
 # automatically registered, the PR CI job configuration will be copied as an
-# Auto CI job but with `continue_on_error` overriden to `false` (to fail-fast).
-# When overriden, `citool` will check for equivalence between the PR and CI job
+# Auto CI job but with `continue_on_error` overridden to `false` (to fail-fast).
+# When overridden, `citool` will check for equivalence between the PR and CI job
 # of the same name modulo `continue_on_error` and `env`.
 pr:
   - name: pr-check-1
@@ -166,7 +166,7 @@ optional:
 #
 # Auto jobs may not specify `continue_on_error: true`, and thus will fail-fast.
 #
-# Unless explicitly overriden, PR CI jobs will be automatically registered as
+# Unless explicitly overridden, PR CI jobs will be automatically registered as
 # Auto CI jobs.
 auto:
   #############################
diff --git a/src/ci/scripts/free-disk-space-linux.sh b/src/ci/scripts/free-disk-space-linux.sh
index 32649fe0d9b34..ac3c9cfb28b87 100755
--- a/src/ci/scripts/free-disk-space-linux.sh
+++ b/src/ci/scripts/free-disk-space-linux.sh
@@ -221,10 +221,13 @@ cleanPackages() {
         )
     fi
 
-    sudo apt-get -qq remove -y --fix-missing "${packages[@]}"
+    WAIT_DPKG_LOCK="-o DPkg::Lock::Timeout=60"
+    sudo apt-get ${WAIT_DPKG_LOCK} -qq remove -y --fix-missing "${packages[@]}"
 
-    sudo apt-get autoremove -y || echo "::warning::The command [sudo apt-get autoremove -y] failed"
-    sudo apt-get clean || echo "::warning::The command [sudo apt-get clean] failed failed"
+    sudo apt-get ${WAIT_DPKG_LOCK} autoremove -y \
+        || echo "::warning::The command [sudo apt-get autoremove -y] failed"
+    sudo apt-get ${WAIT_DPKG_LOCK} clean \
+        || echo "::warning::The command [sudo apt-get clean] failed"
 }
 
 # Remove Docker images.
diff --git a/src/doc/nomicon b/src/doc/nomicon
index 3ff384320598b..57ed447366056 160000
--- a/src/doc/nomicon
+++ b/src/doc/nomicon
@@ -1 +1 @@
-Subproject commit 3ff384320598bbe8d8cfe5cb8f18f78a3a3e6b15
+Subproject commit 57ed4473660565d9357fcae176b358d7e8724ebf
diff --git a/src/doc/reference b/src/doc/reference
index 59b8af8118863..89f67b3c1b904 160000
--- a/src/doc/reference
+++ b/src/doc/reference
@@ -1 +1 @@
-Subproject commit 59b8af811886313577615c2cf0e045f01faed88b
+Subproject commit 89f67b3c1b904cbcd9ed55e443d6fc67c8ca2769
diff --git a/src/doc/rust-by-example b/src/doc/rust-by-example
index adc1f3b9012ad..ad27f82c18464 160000
--- a/src/doc/rust-by-example
+++ b/src/doc/rust-by-example
@@ -1 +1 @@
-Subproject commit adc1f3b9012ad3255eea2054ca30596a953d053d
+Subproject commit ad27f82c18464525c761a4a8db2e01785da59e1f
diff --git a/src/doc/rustc/src/command-line-arguments/print-options.md b/src/doc/rustc/src/command-line-arguments/print-options.md
index 1f33e91e5d1b6..fed19d6b667e9 100644
--- a/src/doc/rustc/src/command-line-arguments/print-options.md
+++ b/src/doc/rustc/src/command-line-arguments/print-options.md
@@ -32,7 +32,7 @@ The names of the files created by the `link` emit kind.
 
 ## `sysroot`
 
-Abosulte path to the sysroot.
+Absolute path to the sysroot.
 
 Example (with rustup and the stable toolchain):
 
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index d891d1fba254a..e2682045ab432 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -11,6 +11,7 @@
 #![feature(file_buffered)]
 #![feature(format_args_nl)]
 #![feature(if_let_guard)]
+#![feature(iter_advance_by)]
 #![feature(iter_intersperse)]
 #![feature(round_char_boundary)]
 #![feature(rustc_private)]
diff --git a/src/librustdoc/passes/lint/html_tags.rs b/src/librustdoc/passes/lint/html_tags.rs
index 19cf15d40a3b4..da09117b1bba7 100644
--- a/src/librustdoc/passes/lint/html_tags.rs
+++ b/src/librustdoc/passes/lint/html_tags.rs
@@ -1,9 +1,11 @@
 //! Detects invalid HTML (like an unclosed `<span>`) in doc comments.
 
+use std::borrow::Cow;
 use std::iter::Peekable;
 use std::ops::Range;
 use std::str::CharIndices;
 
+use itertools::Itertools as _;
 use pulldown_cmark::{BrokenLink, Event, LinkType, Parser, Tag, TagEnd};
 use rustc_hir::HirId;
 use rustc_resolve::rustdoc::source_span_for_markdown_range;
@@ -101,7 +103,7 @@ pub(crate) fn visit_item(cx: &DocContext<'_>, item: &Item, hir_id: HirId, dox: &
         });
     };
 
-    let mut tags = Vec::new();
+    let mut tagp = TagParser::new();
     let mut is_in_comment = None;
     let mut in_code_block = false;
 
@@ -126,70 +128,65 @@ pub(crate) fn visit_item(cx: &DocContext<'_>, item: &Item, hir_id: HirId, dox: &
     };
 
     let p = Parser::new_with_broken_link_callback(dox, main_body_opts(), Some(&mut replacer))
-        .into_offset_iter();
+        .into_offset_iter()
+        .coalesce(|a, b| {
+            // for some reason, pulldown-cmark splits html blocks into separate events for each line.
+            // we undo this, in order to handle multi-line tags.
+            match (a, b) {
+                ((Event::Html(_), ra), (Event::Html(_), rb)) if ra.end == rb.start => {
+                    let merged = ra.start..rb.end;
+                    Ok((Event::Html(Cow::Borrowed(&dox[merged.clone()]).into()), merged))
+                }
+                x => Err(x),
+            }
+        });
 
     for (event, range) in p {
         match event {
             Event::Start(Tag::CodeBlock(_)) => in_code_block = true,
             Event::Html(text) | Event::InlineHtml(text) if !in_code_block => {
-                extract_tags(&mut tags, &text, range, &mut is_in_comment, &report_diag)
+                tagp.extract_tags(&text, range, &mut is_in_comment, &report_diag)
             }
             Event::End(TagEnd::CodeBlock) => in_code_block = false,
             _ => {}
         }
     }
 
-    for (tag, range) in tags.iter().filter(|(t, _)| {
-        let t = t.to_lowercase();
-        !ALLOWED_UNCLOSED.contains(&t.as_str())
-    }) {
-        report_diag(format!("unclosed HTML tag `{tag}`"), range, true);
-    }
-
     if let Some(range) = is_in_comment {
         report_diag("Unclosed HTML comment".to_string(), &range, false);
+    } else if let &Some(quote_pos) = &tagp.quote_pos {
+        let qr = Range { start: quote_pos, end: quote_pos };
+        report_diag(
+            format!("unclosed quoted HTML attribute on tag `{}`", &tagp.tag_name),
+            &qr,
+            false,
+        );
+    } else {
+        if !tagp.tag_name.is_empty() {
+            report_diag(
+                format!("incomplete HTML tag `{}`", &tagp.tag_name),
+                &(tagp.tag_start_pos..dox.len()),
+                false,
+            );
+        }
+        for (tag, range) in tagp.tags.iter().filter(|(t, _)| {
+            let t = t.to_lowercase();
+            !is_implicitly_self_closing(&t)
+        }) {
+            report_diag(format!("unclosed HTML tag `{tag}`"), range, true);
+        }
     }
 }
 
+/// These tags are interpreted as self-closing if they lack an explicit closing tag.
 const ALLOWED_UNCLOSED: &[&str] = &[
     "area", "base", "br", "col", "embed", "hr", "img", "input", "keygen", "link", "meta", "param",
     "source", "track", "wbr",
 ];
 
-fn drop_tag(
-    tags: &mut Vec<(String, Range<usize>)>,
-    tag_name: String,
-    range: Range<usize>,
-    f: &impl Fn(String, &Range<usize>, bool),
-) {
-    let tag_name_low = tag_name.to_lowercase();
-    if let Some(pos) = tags.iter().rposition(|(t, _)| t.to_lowercase() == tag_name_low) {
-        // If the tag is nested inside a "<script>" or a "<style>" tag, no warning should
-        // be emitted.
-        let should_not_warn = tags.iter().take(pos + 1).any(|(at, _)| {
-            let at = at.to_lowercase();
-            at == "script" || at == "style"
-        });
-        for (last_tag_name, last_tag_span) in tags.drain(pos + 1..) {
-            if should_not_warn {
-                continue;
-            }
-            let last_tag_name_low = last_tag_name.to_lowercase();
-            if ALLOWED_UNCLOSED.contains(&last_tag_name_low.as_str()) {
-                continue;
-            }
-            // `tags` is used as a queue, meaning that everything after `pos` is included inside it.
-            // So `<h2><h3></h2>` will look like `["h2", "h3"]`. So when closing `h2`, we will still
-            // have `h3`, meaning the tag wasn't closed as it should have.
-            f(format!("unclosed HTML tag `{last_tag_name}`"), &last_tag_span, true);
-        }
-        // Remove the `tag_name` that was originally closed
-        tags.pop();
-    } else {
-        // It can happen for example in this case: `<h2></script></h2>` (the `h2` tag isn't required
-        // but it helps for the visualization).
-        f(format!("unopened HTML tag `{tag_name}`"), &range, false);
-    }
+/// Allows constructs like `<img>`, but not `<img`.
+fn is_implicitly_self_closing(tag_name: &str) -> bool {
+    ALLOWED_UNCLOSED.contains(&tag_name)
 }
 
 fn extract_path_backwards(text: &str, end_pos: usize) -> Option<usize> {
@@ -252,151 +249,292 @@ fn is_valid_for_html_tag_name(c: char, is_empty: bool) -> bool {
     c.is_ascii_alphabetic() || !is_empty && (c == '-' || c.is_ascii_digit())
 }
 
-fn extract_html_tag(
-    tags: &mut Vec<(String, Range<usize>)>,
-    text: &str,
-    range: &Range<usize>,
-    start_pos: usize,
-    iter: &mut Peekable<CharIndices<'_>>,
-    f: &impl Fn(String, &Range<usize>, bool),
-) {
-    let mut tag_name = String::new();
-    let mut is_closing = false;
-    let mut prev_pos = start_pos;
+/// Parse html tags to ensure they are well-formed
+#[derive(Debug, Clone)]
+struct TagParser {
+    tags: Vec<(String, Range<usize>)>,
+    /// Name of the tag that is being parsed, if we are within a tag.
+    ///
+    /// Since the `<` and name of a tag must appear on the same line with no whitespace,
+    /// if this is the empty string, we are not in a tag.
+    tag_name: String,
+    tag_start_pos: usize,
+    is_closing: bool,
+    /// `true` if we are within a tag, but not within its name.
+    in_attrs: bool,
+    /// If we are in a quoted attribute, what quote char does it use?
+    ///
+    /// This needs to be stored in the struct since HTML5 allows newlines in quoted attrs.
+    quote: Option<char>,
+    quote_pos: Option<usize>,
+    after_eq: bool,
+}
 
-    loop {
-        let (pos, c) = match iter.peek() {
-            Some((pos, c)) => (*pos, *c),
-            // In case we reached the of the doc comment, we want to check that it's an
-            // unclosed HTML tag. For example "/// <h3".
-            None => (prev_pos, '\0'),
-        };
-        prev_pos = pos;
-        // Checking if this is a closing tag (like `</a>` for `<a>`).
-        if c == '/' && tag_name.is_empty() {
-            is_closing = true;
-        } else if is_valid_for_html_tag_name(c, tag_name.is_empty()) {
-            tag_name.push(c);
-        } else {
-            if !tag_name.is_empty() {
-                let mut r = Range { start: range.start + start_pos, end: range.start + pos };
-                if c == '>' {
-                    // In case we have a tag without attribute, we can consider the span to
-                    // refer to it fully.
-                    r.end += 1;
+impl TagParser {
+    fn new() -> Self {
+        Self {
+            tags: Vec::new(),
+            tag_name: String::with_capacity(8),
+            tag_start_pos: 0,
+            is_closing: false,
+            in_attrs: false,
+            quote: None,
+            quote_pos: None,
+            after_eq: false,
+        }
+    }
+
+    fn drop_tag(&mut self, range: Range<usize>, f: &impl Fn(String, &Range<usize>, bool)) {
+        let tag_name_low = self.tag_name.to_lowercase();
+        if let Some(pos) = self.tags.iter().rposition(|(t, _)| t.to_lowercase() == tag_name_low) {
+            // If the tag is nested inside a "<script>" or a "<style>" tag, no warning should
+            // be emitted.
+            let should_not_warn = self.tags.iter().take(pos + 1).any(|(at, _)| {
+                let at = at.to_lowercase();
+                at == "script" || at == "style"
+            });
+            for (last_tag_name, last_tag_span) in self.tags.drain(pos + 1..) {
+                if should_not_warn {
+                    continue;
                 }
-                if is_closing {
-                    // In case we have "</div >" or even "</div         >".
-                    if c != '>' {
-                        if !c.is_whitespace() {
-                            // It seems like it's not a valid HTML tag.
-                            break;
-                        }
-                        let mut found = false;
-                        for (new_pos, c) in text[pos..].char_indices() {
+                let last_tag_name_low = last_tag_name.to_lowercase();
+                if is_implicitly_self_closing(&last_tag_name_low) {
+                    continue;
+                }
+                // `tags` is used as a queue, meaning that everything after `pos` is included inside it.
+                // So `<h2><h3></h2>` will look like `["h2", "h3"]`. So when closing `h2`, we will still
+                // have `h3`, meaning the tag wasn't closed as it should have.
+                f(format!("unclosed HTML tag `{last_tag_name}`"), &last_tag_span, true);
+            }
+            // Remove the `tag_name` that was originally closed
+            self.tags.pop();
+        } else {
+            // It can happen for example in this case: `<h2></script></h2>` (the `h2` tag isn't required
+            // but it helps for the visualization).
+            f(format!("unopened HTML tag `{}`", &self.tag_name), &range, false);
+        }
+    }
+
+    /// Handle a `<` that appeared while parsing a tag.
+    fn handle_lt_in_tag(
+        &mut self,
+        range: Range<usize>,
+        lt_pos: usize,
+        f: &impl Fn(String, &Range<usize>, bool),
+    ) {
+        let global_pos = range.start + lt_pos;
+        // is this check needed?
+        if global_pos == self.tag_start_pos {
+            // `<` is in the tag because it is the start.
+            return;
+        }
+        // tried to start a new tag while in a tag
+        f(
+            format!("incomplete HTML tag `{}`", &self.tag_name),
+            &(self.tag_start_pos..global_pos),
+            false,
+        );
+        self.tag_parsed();
+    }
+
+    fn extract_html_tag(
+        &mut self,
+        text: &str,
+        range: &Range<usize>,
+        start_pos: usize,
+        iter: &mut Peekable<CharIndices<'_>>,
+        f: &impl Fn(String, &Range<usize>, bool),
+    ) {
+        let mut prev_pos = start_pos;
+
+        'outer_loop: loop {
+            let (pos, c) = match iter.peek() {
+                Some((pos, c)) => (*pos, *c),
+                // In case we reached the of the doc comment, we want to check that it's an
+                // unclosed HTML tag. For example "/// <h3".
+                None if self.tag_name.is_empty() => (prev_pos, '\0'),
+                None => break,
+            };
+            prev_pos = pos;
+            if c == '/' && self.tag_name.is_empty() {
+                // Checking if this is a closing tag (like `</a>` for `<a>`).
+                self.is_closing = true;
+            } else if !self.in_attrs && is_valid_for_html_tag_name(c, self.tag_name.is_empty()) {
+                self.tag_name.push(c);
+            } else {
+                if !self.tag_name.is_empty() {
+                    self.in_attrs = true;
+                    let mut r = Range { start: range.start + start_pos, end: range.start + pos };
+                    if c == '>' {
+                        // In case we have a tag without attribute, we can consider the span to
+                        // refer to it fully.
+                        r.end += 1;
+                    }
+                    if self.is_closing {
+                        // In case we have "</div >" or even "</div         >".
+                        if c != '>' {
                             if !c.is_whitespace() {
-                                if c == '>' {
-                                    r.end = range.start + new_pos + 1;
-                                    found = true;
-                                }
+                                // It seems like it's not a valid HTML tag.
                                 break;
                             }
-                        }
-                        if !found {
-                            break;
-                        }
-                    }
-                    drop_tag(tags, tag_name, r, f);
-                } else {
-                    let mut is_self_closing = false;
-                    let mut quote_pos = None;
-                    if c != '>' {
-                        let mut quote = None;
-                        let mut after_eq = false;
-                        for (i, c) in text[pos..].char_indices() {
-                            if !c.is_whitespace() {
-                                if let Some(q) = quote {
-                                    if c == q {
-                                        quote = None;
-                                        quote_pos = None;
-                                        after_eq = false;
+                            let mut found = false;
+                            for (new_pos, c) in text[pos..].char_indices() {
+                                if !c.is_whitespace() {
+                                    if c == '>' {
+                                        r.end = range.start + new_pos + 1;
+                                        found = true;
+                                    } else if c == '<' {
+                                        self.handle_lt_in_tag(range.clone(), pos + new_pos, f);
                                     }
-                                } else if c == '>' {
                                     break;
-                                } else if c == '/' && !after_eq {
-                                    is_self_closing = true;
-                                } else {
-                                    if is_self_closing {
-                                        is_self_closing = false;
-                                    }
-                                    if (c == '"' || c == '\'') && after_eq {
-                                        quote = Some(c);
-                                        quote_pos = Some(pos + i);
-                                    } else if c == '=' {
-                                        after_eq = true;
-                                    }
                                 }
-                            } else if quote.is_none() {
-                                after_eq = false;
+                            }
+                            if !found {
+                                break 'outer_loop;
                             }
                         }
-                    }
-                    if let Some(quote_pos) = quote_pos {
-                        let qr = Range { start: quote_pos, end: quote_pos };
-                        f(
-                            format!("unclosed quoted HTML attribute on tag `{tag_name}`"),
-                            &qr,
-                            false,
-                        );
-                    }
-                    if is_self_closing {
-                        // https://html.spec.whatwg.org/#parse-error-non-void-html-element-start-tag-with-trailing-solidus
-                        let valid = ALLOWED_UNCLOSED.contains(&&tag_name[..])
-                            || tags.iter().take(pos + 1).any(|(at, _)| {
-                                let at = at.to_lowercase();
-                                at == "svg" || at == "math"
-                            });
-                        if !valid {
-                            f(format!("invalid self-closing HTML tag `{tag_name}`"), &r, false);
-                        }
+                        self.drop_tag(r, f);
+                        self.tag_parsed();
                     } else {
-                        tags.push((tag_name, r));
+                        self.extract_opening_tag(text, range, r, pos, c, iter, f)
                     }
                 }
+                break;
             }
-            break;
+            iter.next();
         }
-        iter.next();
     }
-}
-
-fn extract_tags(
-    tags: &mut Vec<(String, Range<usize>)>,
-    text: &str,
-    range: Range<usize>,
-    is_in_comment: &mut Option<Range<usize>>,
-    f: &impl Fn(String, &Range<usize>, bool),
-) {
-    let mut iter = text.char_indices().peekable();
 
-    while let Some((start_pos, c)) = iter.next() {
-        if is_in_comment.is_some() {
-            if text[start_pos..].starts_with("-->") {
-                *is_in_comment = None;
+    fn extract_opening_tag(
+        &mut self,
+        text: &str,
+        range: &Range<usize>,
+        r: Range<usize>,
+        pos: usize,
+        c: char,
+        iter: &mut Peekable<CharIndices<'_>>,
+        f: &impl Fn(String, &Range<usize>, bool),
+    ) {
+        // we can store this as a local, since html5 does require the `/` and `>`
+        // to not be separated by whitespace.
+        let mut is_self_closing = false;
+        if c != '>' {
+            'parse_til_gt: {
+                for (i, c) in text[pos..].char_indices() {
+                    if !c.is_whitespace() {
+                        debug_assert_eq!(self.quote_pos.is_some(), self.quote.is_some());
+                        if let Some(q) = self.quote {
+                            if c == q {
+                                self.quote = None;
+                                self.quote_pos = None;
+                                self.after_eq = false;
+                            }
+                        } else if c == '>' {
+                            break 'parse_til_gt;
+                        } else if c == '<' {
+                            self.handle_lt_in_tag(range.clone(), pos + i, f);
+                        } else if c == '/' && !self.after_eq {
+                            is_self_closing = true;
+                        } else {
+                            if is_self_closing {
+                                is_self_closing = false;
+                            }
+                            if (c == '"' || c == '\'') && self.after_eq {
+                                self.quote = Some(c);
+                                self.quote_pos = Some(pos + i);
+                            } else if c == '=' {
+                                self.after_eq = true;
+                            }
+                        }
+                    } else if self.quote.is_none() {
+                        self.after_eq = false;
+                    }
+                    if !is_self_closing && !self.tag_name.is_empty() {
+                        iter.next();
+                    }
+                }
+                // if we've run out of text but still haven't found a `>`,
+                // return early without calling `tag_parsed` or emitting lints.
+                // this allows us to either find the `>` in a later event
+                // or emit a lint about it being missing.
+                return;
             }
-        } else if c == '<' {
-            if text[start_pos..].starts_with("<!--") {
-                // We skip the "!--" part. (Once `advance_by` is stable, might be nice to use it!)
-                iter.next();
-                iter.next();
-                iter.next();
-                *is_in_comment = Some(Range {
-                    start: range.start + start_pos,
-                    end: range.start + start_pos + 3,
+        }
+        if is_self_closing {
+            // https://html.spec.whatwg.org/#parse-error-non-void-html-element-start-tag-with-trailing-solidus
+            let valid = ALLOWED_UNCLOSED.contains(&&self.tag_name[..])
+                || self.tags.iter().take(pos + 1).any(|(at, _)| {
+                    let at = at.to_lowercase();
+                    at == "svg" || at == "math"
                 });
-            } else {
-                extract_html_tag(tags, text, &range, start_pos, &mut iter, f);
+            if !valid {
+                f(format!("invalid self-closing HTML tag `{}`", self.tag_name), &r, false);
+            }
+        } else if !self.tag_name.is_empty() {
+            self.tags.push((std::mem::take(&mut self.tag_name), r));
+        }
+        self.tag_parsed();
+    }
+    /// Finished parsing a tag, reset related data.
+    fn tag_parsed(&mut self) {
+        self.tag_name.clear();
+        self.is_closing = false;
+        self.in_attrs = false;
+    }
+
+    fn extract_tags(
+        &mut self,
+        text: &str,
+        range: Range<usize>,
+        is_in_comment: &mut Option<Range<usize>>,
+        f: &impl Fn(String, &Range<usize>, bool),
+    ) {
+        let mut iter = text.char_indices().peekable();
+        let mut prev_pos = 0;
+        loop {
+            if self.quote.is_some() {
+                debug_assert!(self.in_attrs && self.quote_pos.is_some());
+            }
+            if self.in_attrs
+                && let Some(&(start_pos, _)) = iter.peek()
+            {
+                self.extract_html_tag(text, &range, start_pos, &mut iter, f);
+                // if no progress is being made, move forward forcefully.
+                if prev_pos == start_pos {
+                    iter.next();
+                }
+                prev_pos = start_pos;
+                continue;
+            }
+            let Some((start_pos, c)) = iter.next() else { break };
+            if is_in_comment.is_some() {
+                if text[start_pos..].starts_with("-->") {
+                    *is_in_comment = None;
+                }
+            } else if c == '<' {
+                // "<!--" is a valid attribute name under html5, so don't treat it as a comment if we're in a tag.
+                if self.tag_name.is_empty() && text[start_pos..].starts_with("<!--") {
+                    // We skip the "!--" part. (Once `advance_by` is stable, might be nice to use it!)
+                    iter.next();
+                    iter.next();
+                    iter.next();
+                    *is_in_comment = Some(Range {
+                        start: range.start + start_pos,
+                        end: range.start + start_pos + 4,
+                    });
+                } else {
+                    if self.tag_name.is_empty() {
+                        self.tag_start_pos = range.start + start_pos;
+                    }
+                    self.extract_html_tag(text, &range, start_pos, &mut iter, f);
+                }
+            } else if !self.tag_name.is_empty() {
+                // partially inside html tag that spans across events
+                self.extract_html_tag(text, &range, start_pos, &mut iter, f);
             }
         }
     }
 }
+
+#[cfg(test)]
+mod tests;
diff --git a/src/librustdoc/passes/lint/html_tags/tests.rs b/src/librustdoc/passes/lint/html_tags/tests.rs
new file mode 100644
index 0000000000000..81c1d21a55d55
--- /dev/null
+++ b/src/librustdoc/passes/lint/html_tags/tests.rs
@@ -0,0 +1,73 @@
+use std::cell::RefCell;
+
+use super::*;
+
+#[test]
+fn test_extract_tags_nested_unclosed() {
+    let mut tagp = TagParser::new();
+    let diags = RefCell::new(Vec::new());
+    let dox = "<div>\n<br</div>";
+    tagp.extract_tags(dox, 0..dox.len(), &mut None, &|s, r, b| {
+        diags.borrow_mut().push((s, r.clone(), b));
+    });
+    assert_eq!(diags.borrow().len(), 1, "did not get expected diagnostics: {diags:?}");
+    assert_eq!(diags.borrow()[0].1, 6..9)
+}
+
+#[test]
+fn test_extract_tags_taglike_in_attr() {
+    let mut tagp = TagParser::new();
+    let diags = RefCell::new(Vec::new());
+    let dox = "<img src='<div>'>";
+    tagp.extract_tags(dox, 0..dox.len(), &mut None, &|s, r, b| {
+        diags.borrow_mut().push((s, r.clone(), b));
+    });
+    assert_eq!(diags.borrow().len(), 0, "unexpected diagnostics: {diags:?}");
+}
+
+#[test]
+fn test_extract_tags_taglike_in_multiline_attr() {
+    let mut tagp = TagParser::new();
+    let diags = RefCell::new(Vec::new());
+    let dox = "<img src=\"\nasd\n<div>\n\">";
+    tagp.extract_tags(dox, 0..dox.len(), &mut None, &|s, r, b| {
+        diags.borrow_mut().push((s, r.clone(), b));
+    });
+    assert_eq!(diags.borrow().len(), 0, "unexpected diagnostics: {diags:?}");
+}
+
+#[test]
+fn test_extract_tags_taglike_in_multievent_attr() {
+    let mut tagp = TagParser::new();
+    let diags = RefCell::new(Vec::new());
+    let dox = "<img src='<div>'>";
+    let split_point = 10;
+    let mut p = |range: Range<usize>| {
+        tagp.extract_tags(&dox[range.clone()], range, &mut None, &|s, r, b| {
+            diags.borrow_mut().push((s, r.clone(), b));
+        })
+    };
+    p(0..split_point);
+    p(split_point..dox.len());
+    assert_eq!(diags.borrow().len(), 0, "unexpected diagnostics: {diags:?}");
+}
+
+#[test]
+fn test_extract_tags_taglike_in_multiline_multievent_attr() {
+    let mut tagp = TagParser::new();
+    let diags = RefCell::new(Vec::new());
+    let dox = "<img src='\n foo:\n </div>\n <p/>\n <div>\n'>";
+    let mut p = |range: Range<usize>| {
+        tagp.extract_tags(&dox[range.clone()], range, &mut None, &|s, r, b| {
+            diags.borrow_mut().push((s, r.clone(), b));
+        })
+    };
+    let mut offset = 0;
+    for ln in dox.split_inclusive('\n') {
+        let new_offset = offset + ln.len();
+        p(offset..new_offset);
+        offset = new_offset;
+    }
+    assert_eq!(diags.borrow().len(), 0, "unexpected diagnostics: {diags:?}");
+    assert_eq!(tagp.tags.len(), 1);
+}
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 739db8fa0950c..c533293e79138 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -412,7 +412,7 @@ impl<'test> TestCx<'test> {
             cmdline: format!("{cmd:?}"),
         };
         self.dump_output(
-            self.config.verbose,
+            self.config.verbose || !proc_res.status.success(),
             &cmd.get_program().to_string_lossy(),
             &proc_res.stdout,
             &proc_res.stderr,
@@ -1486,7 +1486,7 @@ impl<'test> TestCx<'test> {
         };
 
         self.dump_output(
-            self.config.verbose,
+            self.config.verbose || (!result.status.success() && self.config.mode != TestMode::Ui),
             &command.get_program().to_string_lossy(),
             &result.stdout,
             &result.stderr,
@@ -2987,6 +2987,7 @@ struct ProcArgs {
     args: Vec<OsString>,
 }
 
+#[derive(Debug)]
 pub struct ProcRes {
     status: ExitStatus,
     stdout: String,
diff --git a/src/tools/rustfmt/tests/source/frontmatter_compact.rs b/src/tools/rustfmt/tests/source/frontmatter_compact.rs
new file mode 100644
index 0000000000000..21d4c6f4b6160
--- /dev/null
+++ b/src/tools/rustfmt/tests/source/frontmatter_compact.rs
@@ -0,0 +1,8 @@
+#!/usr/bin/env cargo
+---identifier
+[dependencies]
+regex = "1"
+---
+#![feature(frontmatter)]
+
+fn main() {}
diff --git a/src/tools/rustfmt/tests/source/frontmatter_escaped.rs b/src/tools/rustfmt/tests/source/frontmatter_escaped.rs
new file mode 100644
index 0000000000000..0d02637756682
--- /dev/null
+++ b/src/tools/rustfmt/tests/source/frontmatter_escaped.rs
@@ -0,0 +1,13 @@
+#!/usr/bin/env cargo
+------------
+package.description = """
+Header
+-----
+
+Body
+"""
+------------
+
+#![feature(frontmatter)]
+
+fn main() {}
diff --git a/src/tools/rustfmt/tests/source/frontmatter_spaced.rs b/src/tools/rustfmt/tests/source/frontmatter_spaced.rs
new file mode 100644
index 0000000000000..ee0bb81705c49
--- /dev/null
+++ b/src/tools/rustfmt/tests/source/frontmatter_spaced.rs
@@ -0,0 +1,16 @@
+#!/usr/bin/env cargo
+
+
+---   identifier
+[dependencies]
+regex = "1"
+
+---
+
+
+
+
+
+#![feature(frontmatter)]
+
+fn main() {}
diff --git a/src/tools/rustfmt/tests/target/frontmatter_compact.rs b/src/tools/rustfmt/tests/target/frontmatter_compact.rs
new file mode 100644
index 0000000000000..21d4c6f4b6160
--- /dev/null
+++ b/src/tools/rustfmt/tests/target/frontmatter_compact.rs
@@ -0,0 +1,8 @@
+#!/usr/bin/env cargo
+---identifier
+[dependencies]
+regex = "1"
+---
+#![feature(frontmatter)]
+
+fn main() {}
diff --git a/src/tools/rustfmt/tests/target/frontmatter_escaped.rs b/src/tools/rustfmt/tests/target/frontmatter_escaped.rs
new file mode 100644
index 0000000000000..0d02637756682
--- /dev/null
+++ b/src/tools/rustfmt/tests/target/frontmatter_escaped.rs
@@ -0,0 +1,13 @@
+#!/usr/bin/env cargo
+------------
+package.description = """
+Header
+-----
+
+Body
+"""
+------------
+
+#![feature(frontmatter)]
+
+fn main() {}
diff --git a/src/tools/rustfmt/tests/target/frontmatter_spaced.rs b/src/tools/rustfmt/tests/target/frontmatter_spaced.rs
new file mode 100644
index 0000000000000..ee0bb81705c49
--- /dev/null
+++ b/src/tools/rustfmt/tests/target/frontmatter_spaced.rs
@@ -0,0 +1,16 @@
+#!/usr/bin/env cargo
+
+
+---   identifier
+[dependencies]
+regex = "1"
+
+---
+
+
+
+
+
+#![feature(frontmatter)]
+
+fn main() {}
diff --git a/src/tools/tidy/src/deps.rs b/src/tools/tidy/src/deps.rs
index 80b6d54ce1c80..18d97a748ba9f 100644
--- a/src/tools/tidy/src/deps.rs
+++ b/src/tools/tidy/src/deps.rs
@@ -361,7 +361,6 @@ const PERMITTED_RUSTC_DEPENDENCIES: &[&str] = &[
     "scoped-tls",
     "scopeguard",
     "self_cell",
-    "semver",
     "serde",
     "serde_derive",
     "serde_json",
diff --git a/src/tools/tidy/src/gcc_submodule.rs b/src/tools/tidy/src/gcc_submodule.rs
index 5d726c3ea48ff..217eaf1758c48 100644
--- a/src/tools/tidy/src/gcc_submodule.rs
+++ b/src/tools/tidy/src/gcc_submodule.rs
@@ -24,6 +24,12 @@ pub fn check(root_path: &Path, compiler_path: &Path, bad: &mut bool) {
         .output()
         .expect("Cannot determine git SHA of the src/gcc checkout");
 
+    // Git is not available or we are in a tarball
+    if !git_output.status.success() {
+        eprintln!("Cannot figure out the SHA of the GCC submodule");
+        return;
+    }
+
     // This can return e.g.
     // -e607be166673a8de9fc07f6f02c60426e556c5f2 src/gcc
     //  e607be166673a8de9fc07f6f02c60426e556c5f2 src/gcc (master-e607be166673a8de9fc07f6f02c60426e556c5f2.e607be)
diff --git a/src/tools/wasm-component-ld/Cargo.toml b/src/tools/wasm-component-ld/Cargo.toml
index ce718902b29fc..23dc86998e88f 100644
--- a/src/tools/wasm-component-ld/Cargo.toml
+++ b/src/tools/wasm-component-ld/Cargo.toml
@@ -10,4 +10,4 @@ name = "wasm-component-ld"
 path = "src/main.rs"
 
 [dependencies]
-wasm-component-ld = "0.5.14"
+wasm-component-ld = "0.5.16"
diff --git a/tests/rustdoc-ui/lints/invalid-html-tags.rs b/tests/rustdoc-ui/lints/invalid-html-tags.rs
index 317f1fd1d4641..8003e5efdd582 100644
--- a/tests/rustdoc-ui/lints/invalid-html-tags.rs
+++ b/tests/rustdoc-ui/lints/invalid-html-tags.rs
@@ -43,7 +43,7 @@ pub fn b() {}
 ///   <h3>
 //~^ ERROR unclosed HTML tag `h3`
 /// <script
-//~^ ERROR unclosed HTML tag `script`
+//~^ ERROR incomplete HTML tag `script`
 pub fn c() {}
 
 // Unclosed tags shouldn't warn if they are nested inside a <script> elem.
@@ -72,6 +72,7 @@ pub fn e() {}
 /// <div></div >
 /// <div></div
 //~^ ERROR unclosed HTML tag `div`
+//~| ERROR incomplete HTML tag `div`
 pub fn f() {}
 
 /// <!---->
@@ -105,7 +106,7 @@ pub fn j() {}
 /// uiapp.run(&env::args().collect::<Vec<_>>());
 /// ```
 ///
-/// <Vec<_> shouldn't warn!
+// <Vec<_> shouldn't warn!
 /// ``````
 pub fn k() {}
 
@@ -121,3 +122,92 @@ pub fn no_error_1() {}
 /// backslashed \<<a href="">
 //~^ ERROR unclosed HTML tag `a`
 pub fn p() {}
+
+/// <svg width="512" height="512" viewBox="0 0 512" fill="none" xmlns="http://www.w3.org/2000/svg">
+///     <rect
+///        width="256"
+///        height="256"
+///        fill="#5064C8"
+///        stroke="black"
+///     />
+/// </svg>
+pub fn no_error_2() {}
+
+/// <div>
+///     <img
+///         src="https://example.com/ferris.png"
+///         width="512"
+///         height="512"
+///     />
+/// </div>
+pub fn no_error_3() {}
+
+/// > <div
+/// > class="foo">
+/// > </div>
+pub fn no_error_4() {}
+
+/// unfinished ALLOWED_UNCLOSED
+///
+/// note: CommonMark doesn't allow an html block to start with a multiline tag,
+/// so we use `<br>` a bunch to force these to be parsed as html blocks.
+///
+/// <br>
+/// <img
+//~^ ERROR incomplete HTML tag `img`
+pub fn q() {}
+
+/// nested unfinished ALLOWED_UNCLOSED
+/// <p><img</p>
+//~^ ERROR incomplete HTML tag `img`
+pub fn r() {}
+
+/// > <br>
+/// > <img
+//~^ ERROR incomplete HTML tag `img`
+/// > href="#broken"
+pub fn s() {}
+
+/// <br>
+/// <br<br>
+//~^ ERROR incomplete HTML tag `br`
+pub fn t() {}
+
+/// <br>
+/// <br
+//~^ ERROR incomplete HTML tag `br`
+pub fn u() {}
+
+/// <a href=">" alt="<">html5 allows this</a>
+pub fn no_error_5() {}
+
+/// <br>
+/// <img title="
+/// html5
+/// allows
+/// multiline
+/// attr
+/// values
+/// these are just text, not tags:
+/// </div>
+/// <p/>
+/// <div>
+/// ">
+pub fn no_error_6() {}
+
+/// <br>
+/// <a href="data:text/html,<!DOCTYPE>
+/// <html>
+/// <body><b>this is allowed for some reason</b></body>
+/// </html>
+/// ">what</a>
+pub fn no_error_7() {}
+
+/// Technically this is allowed per the html5 spec,
+/// but there's basically no legitemate reason to do it,
+/// so we don't allow it.
+///
+/// <p <!-->foobar</p>
+//~^ ERROR Unclosed HTML comment
+//~| ERROR incomplete HTML tag `p`
+pub fn v() {}
diff --git a/tests/rustdoc-ui/lints/invalid-html-tags.stderr b/tests/rustdoc-ui/lints/invalid-html-tags.stderr
index 9c2bfcf2c3dd7..b6ec22c247901 100644
--- a/tests/rustdoc-ui/lints/invalid-html-tags.stderr
+++ b/tests/rustdoc-ui/lints/invalid-html-tags.stderr
@@ -52,6 +52,12 @@ error: unclosed HTML tag `p`
 LL | ///    <br/> <p>
    |              ^^^
 
+error: incomplete HTML tag `script`
+  --> $DIR/invalid-html-tags.rs:45:5
+   |
+LL | /// <script
+   |     ^^^^^^^
+
 error: unclosed HTML tag `div`
   --> $DIR/invalid-html-tags.rs:41:5
    |
@@ -64,11 +70,11 @@ error: unclosed HTML tag `h3`
 LL | ///   <h3>
    |       ^^^^
 
-error: unclosed HTML tag `script`
-  --> $DIR/invalid-html-tags.rs:45:5
+error: incomplete HTML tag `div`
+  --> $DIR/invalid-html-tags.rs:73:10
    |
-LL | /// <script
-   |     ^^^^^^
+LL | /// <div></div
+   |          ^^^^^
 
 error: unclosed HTML tag `div`
   --> $DIR/invalid-html-tags.rs:73:5
@@ -77,28 +83,73 @@ LL | /// <div></div
    |     ^^^^^
 
 error: Unclosed HTML comment
-  --> $DIR/invalid-html-tags.rs:87:5
+  --> $DIR/invalid-html-tags.rs:88:5
    |
 LL | /// <!--
-   |     ^^^
+   |     ^^^^
 
 error: unopened HTML tag `unopened-tag`
-  --> $DIR/invalid-html-tags.rs:114:26
+  --> $DIR/invalid-html-tags.rs:115:26
    |
 LL | /// Web Components style </unopened-tag>
    |                          ^^^^^^^^^^^^^^^
 
 error: unclosed HTML tag `dashed-tags`
-  --> $DIR/invalid-html-tags.rs:112:26
+  --> $DIR/invalid-html-tags.rs:113:26
    |
 LL | /// Web Components style <dashed-tags>
    |                          ^^^^^^^^^^^^^
 
 error: unclosed HTML tag `a`
-  --> $DIR/invalid-html-tags.rs:121:19
+  --> $DIR/invalid-html-tags.rs:122:19
    |
 LL | /// backslashed \<<a href="">
    |                   ^^
 
-error: aborting due to 16 previous errors
+error: incomplete HTML tag `img`
+  --> $DIR/invalid-html-tags.rs:156:5
+   |
+LL | /// <img
+   |     ^^^^
+
+error: incomplete HTML tag `img`
+  --> $DIR/invalid-html-tags.rs:161:8
+   |
+LL | /// <p><img</p>
+   |        ^^^^
+
+error: incomplete HTML tag `img`
+  --> $DIR/invalid-html-tags.rs:166:7
+   |
+LL |   /// > <img
+   |  _______^
+LL | |
+LL | | /// > href="#broken"
+   | |____________________^
+
+error: incomplete HTML tag `br`
+  --> $DIR/invalid-html-tags.rs:172:5
+   |
+LL | /// <br<br>
+   |     ^^^
+
+error: incomplete HTML tag `br`
+  --> $DIR/invalid-html-tags.rs:177:5
+   |
+LL | /// <br
+   |     ^^^
+
+error: incomplete HTML tag `p`
+  --> $DIR/invalid-html-tags.rs:210:5
+   |
+LL | /// <p <!-->foobar</p>
+   |     ^^^
+
+error: Unclosed HTML comment
+  --> $DIR/invalid-html-tags.rs:210:8
+   |
+LL | /// <p <!-->foobar</p>
+   |        ^^^^
+
+error: aborting due to 24 previous errors
 
diff --git a/tests/ui/consts/ptr_comparisons.rs b/tests/ui/consts/ptr_comparisons.rs
index e142ab3a754a4..b8d809475cf74 100644
--- a/tests/ui/consts/ptr_comparisons.rs
+++ b/tests/ui/consts/ptr_comparisons.rs
@@ -1,43 +1,205 @@
 //@ compile-flags: --crate-type=lib
 //@ check-pass
+//@ edition: 2024
+#![feature(const_raw_ptr_comparison)]
+#![feature(fn_align)]
+// Generally:
+// For any `Some` return, `None` would also be valid, unless otherwise noted.
+// For any `None` return, only `None` is valid, unless otherwise noted.
 
-#![feature(
-    core_intrinsics,
-    const_raw_ptr_comparison,
-)]
+macro_rules! do_test {
+    ($a:expr, $b:expr, $expected:pat) => {
+        const _: () = {
+            let a: *const _ = $a;
+            let b: *const _ = $b;
+            assert!(matches!(<*const u8>::guaranteed_eq(a.cast(), b.cast()), $expected));
+        };
+    };
+}
 
-const FOO: &usize = &42;
+#[repr(align(2))]
+struct T(#[allow(unused)] u16);
 
-macro_rules! check {
-    (eq, $a:expr, $b:expr) => {
-        pub const _: () =
-            assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 1);
-    };
-    (ne, $a:expr, $b:expr) => {
-        pub const _: () =
-            assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 0);
+#[repr(align(2))]
+struct AlignedZst;
+
+static A: T = T(42);
+static B: T = T(42);
+static mut MUT_STATIC: T = T(42);
+static ZST: () = ();
+static ALIGNED_ZST: AlignedZst = AlignedZst;
+static LARGE_WORD_ALIGNED: [usize; 2] = [0, 1];
+static mut MUT_LARGE_WORD_ALIGNED: [usize; 2] = [0, 1];
+
+const FN_PTR: *const () = {
+    fn foo() {}
+    unsafe { std::mem::transmute(foo as fn()) }
+};
+
+const ALIGNED_FN_PTR: *const () = {
+    #[rustc_align(2)]
+    fn aligned_foo() {}
+    unsafe { std::mem::transmute(aligned_foo as fn()) }
+};
+
+trait Trait {
+    #[allow(unused)]
+    fn method(&self) -> u8;
+}
+impl Trait for u32 {
+    fn method(&self) -> u8 { 1 }
+}
+impl Trait for i32 {
+    fn method(&self) -> u8 { 2 }
+}
+
+const VTABLE_PTR_1: *const () = {
+    let [_data, vtable] = unsafe {
+        std::mem::transmute::<&dyn Trait, [*const (); 2]>(&42_u32 as &dyn Trait)
     };
-    (!, $a:expr, $b:expr) => {
-        pub const _: () =
-            assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 2);
+    vtable
+};
+const VTABLE_PTR_2: *const () = {
+    let [_data, vtable] = unsafe {
+        std::mem::transmute::<&dyn Trait, [*const (); 2]>(&42_i32 as &dyn Trait)
     };
-}
+    vtable
+};
 
-check!(eq, 0, 0);
-check!(ne, 0, 1);
-check!(ne, FOO as *const _, 0);
-check!(ne, unsafe { (FOO as *const usize).offset(1) }, 0);
-check!(ne, unsafe { (FOO as *const usize as *const u8).offset(3) }, 0);
+// Cannot be `None`: `is_null` is stable with strong guarantees about integer-valued pointers.
+do_test!(0 as *const u8, 0 as *const u8, Some(true));
+do_test!(0 as *const u8, 1 as *const u8, Some(false));
 
-// We want pointers to be equal to themselves, but aren't checking this yet because
-// there are some open questions (e.g. whether function pointers to the same function
-// compare equal: they don't necessarily do at runtime).
-check!(!, FOO as *const _, FOO as *const _);
+// Integer-valued pointers can always be compared.
+do_test!(1 as *const u8, 1 as *const u8, Some(true));
+do_test!(1 as *const u8, 2 as *const u8, Some(false));
+
+// Cannot be `None`: `static`s' addresses, references, (and within and one-past-the-end of those),
+// and `fn` pointers cannot be null, and `is_null` is stable with strong guarantees, and
+// `is_null` is implemented using `guaranteed_cmp`.
+do_test!(&A, 0 as *const u8, Some(false));
+do_test!((&raw const A).cast::<u8>().wrapping_add(1), 0 as *const u8, Some(false));
+do_test!((&raw const A).wrapping_add(1), 0 as *const u8, Some(false));
+do_test!(&ZST, 0 as *const u8, Some(false));
+do_test!(&(), 0 as *const u8, Some(false));
+do_test!(const { &() }, 0 as *const u8, Some(false));
+do_test!(FN_PTR, 0 as *const u8, Some(false));
+
+// This pointer is out-of-bounds, but still cannot be equal to 0 because of alignment.
+do_test!((&raw const A).cast::<u8>().wrapping_add(size_of::<T>() + 1), 0 as *const u8, Some(false));
 
 // aside from 0, these pointers might end up pretty much anywhere.
-check!(!, FOO as *const _, 1); // this one could be `ne` by taking into account alignment
-check!(!, FOO as *const _, 1024);
+do_test!(&A, align_of::<T>() as *const u8, None);
+do_test!((&raw const A).wrapping_byte_add(1), (align_of::<T>() + 1) as *const u8, None);
+
+// except that they must still be aligned
+do_test!(&A, 1 as *const u8, Some(false));
+do_test!((&raw const A).wrapping_byte_add(1), align_of::<T>() as *const u8, Some(false));
+
+// If `ptr.wrapping_sub(int)` cannot be null (because it is in-bounds or one-past-the-end of
+// `ptr`'s allocation, or because it is misaligned from `ptr`'s allocation), then we know that
+// `ptr != int`, even if `ptr` itself is out-of-bounds or one-past-the-end of its allocation.
+do_test!((&raw const A).wrapping_byte_add(1), 1 as *const u8, Some(false));
+do_test!((&raw const A).wrapping_byte_add(2), 2 as *const u8, Some(false));
+do_test!((&raw const A).wrapping_byte_add(3), 1 as *const u8, Some(false));
+do_test!((&raw const ZST).wrapping_byte_add(1), 1 as *const u8, Some(false));
+do_test!(VTABLE_PTR_1.wrapping_byte_add(1), 1 as *const u8, Some(false));
+do_test!(FN_PTR.wrapping_byte_add(1), 1 as *const u8, Some(false));
+do_test!(&A, size_of::<T>().wrapping_neg() as *const u8, Some(false));
+do_test!(&LARGE_WORD_ALIGNED, size_of::<usize>().wrapping_neg() as *const u8, Some(false));
+// (`ptr - int != 0` due to misalignment)
+do_test!((&raw const A).wrapping_byte_add(2), 1 as *const u8, Some(false));
+do_test!((&raw const ALIGNED_ZST).wrapping_byte_add(2), 1 as *const u8, Some(false));
 
 // When pointers go out-of-bounds, they *might* become null, so these comparions cannot work.
-check!(!, unsafe { (FOO as *const usize).wrapping_add(2) }, 0);
-check!(!, unsafe { (FOO as *const usize).wrapping_sub(1) }, 0);
+do_test!((&raw const A).wrapping_add(2), 0 as *const u8, None);
+do_test!((&raw const A).wrapping_sub(1), 0 as *const u8, None);
+
+// Statics cannot be duplicated
+do_test!(&A, &A, Some(true));
+
+// Two non-ZST statics cannot have the same address
+do_test!(&A, &B, Some(false));
+do_test!(&A, &raw const MUT_STATIC, Some(false));
+
+// One-past-the-end of one static can be equal to the address of another static.
+do_test!(&A, (&raw const B).wrapping_add(1), None);
+
+// Cannot know if ZST static is at the same address with anything non-null (if alignment allows).
+do_test!(&A, &ZST, None);
+do_test!(&A, &ALIGNED_ZST, None);
+
+// Unclear if ZST statics can be placed "in the middle of" non-ZST statics.
+// For now, we conservatively say they could, and return None here.
+do_test!(&ZST, (&raw const A).wrapping_byte_add(1), None);
+
+// As per https://doc.rust-lang.org/nightly/reference/items/static-items.html#r-items.static.storage-disjointness
+// immutable statics are allowed to overlap with const items and promoteds.
+do_test!(&A, &T(42), None);
+do_test!(&A, const { &T(42) }, None);
+do_test!(&A, { const X: T = T(42); &X }, None);
+
+// These could return Some(false), since only immutable statics can overlap with const items
+// and promoteds.
+do_test!(&raw const MUT_STATIC, &T(42), None);
+do_test!(&raw const MUT_STATIC, const { &T(42) }, None);
+do_test!(&raw const MUT_STATIC, { const X: T = T(42); &X }, None);
+
+// An odd offset from a 2-aligned allocation can never be equal to an even offset from a
+// 2-aligned allocation, even if the offsets are out-of-bounds.
+do_test!(&A, (&raw const B).wrapping_byte_add(1), Some(false));
+do_test!(&A, (&raw const B).wrapping_byte_add(5), Some(false));
+do_test!(&A, (&raw const ALIGNED_ZST).wrapping_byte_add(1), Some(false));
+do_test!(&ALIGNED_ZST, (&raw const A).wrapping_byte_add(1), Some(false));
+do_test!(&A, (&T(42) as *const T).wrapping_byte_add(1), Some(false));
+do_test!(&A, (const { &T(42) } as *const T).wrapping_byte_add(1), Some(false));
+do_test!(&A, ({ const X: T = T(42); &X } as *const T).wrapping_byte_add(1), Some(false));
+
+// We could return `Some(false)` for these, as pointers to different statics can never be equal if
+// that would require the statics to overlap, even if the pointers themselves are offset out of
+// bounds or one-past-the-end. We currently only check strictly in-bounds pointers when comparing
+// pointers to different statics, however.
+do_test!((&raw const A).wrapping_add(1), (&raw const B).wrapping_add(1), None);
+do_test!(
+    (&raw const LARGE_WORD_ALIGNED).cast::<usize>().wrapping_add(2),
+    (&raw const MUT_LARGE_WORD_ALIGNED).cast::<usize>().wrapping_add(1),
+    None
+);
+
+// Pointers into the same static are equal if and only if their offset is the same,
+// even if either is out-of-bounds.
+do_test!(&A, &A, Some(true));
+do_test!(&A, &A.0, Some(true));
+do_test!(&A, (&raw const A).wrapping_byte_add(1), Some(false));
+do_test!(&A, (&raw const A).wrapping_byte_add(2), Some(false));
+do_test!(&A, (&raw const A).wrapping_byte_add(51), Some(false));
+do_test!((&raw const A).wrapping_byte_add(51), (&raw const A).wrapping_byte_add(51), Some(true));
+
+// Pointers to the same fn may be unequal, since `fn`s can be duplicated.
+do_test!(FN_PTR, FN_PTR, None);
+do_test!(ALIGNED_FN_PTR, ALIGNED_FN_PTR, None);
+
+// Pointers to different fns may be equal, since `fn`s can be deduplicated.
+do_test!(FN_PTR, ALIGNED_FN_PTR, None);
+
+// Pointers to the same vtable may be unequal, since vtables can be duplicated.
+do_test!(VTABLE_PTR_1, VTABLE_PTR_1, None);
+
+// Pointers to different vtables may be equal, since vtables can be deduplicated.
+do_test!(VTABLE_PTR_1, VTABLE_PTR_2, None);
+
+// Function pointers to aligned function allocations are not necessarily actually aligned,
+// due to platform-specific semantics.
+// See https://github.com/rust-lang/rust/issues/144661
+// FIXME: This could return `Some` on platforms where function pointers' addresses actually
+// correspond to function addresses including alignment, or on platforms where all functions
+// are aligned to some amount (e.g. ARM where a32 function pointers are at least 4-aligned,
+// and t32 function pointers are 2-aligned-offset-by-1).
+do_test!(ALIGNED_FN_PTR, ALIGNED_FN_PTR.wrapping_byte_offset(1), None);
+
+// Conservatively say we don't know.
+do_test!(FN_PTR, VTABLE_PTR_1, None);
+do_test!((&raw const LARGE_WORD_ALIGNED).cast::<usize>().wrapping_add(1), VTABLE_PTR_1, None);
+do_test!((&raw const MUT_LARGE_WORD_ALIGNED).cast::<usize>().wrapping_add(1), VTABLE_PTR_1, None);
+do_test!((&raw const LARGE_WORD_ALIGNED).cast::<usize>().wrapping_add(1), FN_PTR, None);
+do_test!((&raw const MUT_LARGE_WORD_ALIGNED).cast::<usize>().wrapping_add(1), FN_PTR, None);