diff --git a/.github/workflows/stdarch.yml b/.github/workflows/stdarch.yml
index 556c6444833..21b6a0d3a93 100644
--- a/.github/workflows/stdarch.yml
+++ b/.github/workflows/stdarch.yml
@@ -133,10 +133,10 @@ jobs:
       if: ${{ !matrix.cargo_runner }}
       run: |
         cd build_sysroot/sysroot_src/library/stdarch/
-        CHANNEL=release TARGET=x86_64-unknown-linux-gnu ../../../../cargo.sh test
+        CHANNEL=release TARGET=x86_64-unknown-linux-gnu CG_RUSTFLAGS="-Ainternal_features" ../../../../cargo.sh test
 
     - name: Run stdarch tests
       if: ${{ matrix.cargo_runner }}
       run: |
         cd build_sysroot/sysroot_src/library/stdarch/
-        STDARCH_TEST_EVERYTHING=1 CHANNEL=release CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUNNER="${{ matrix.cargo_runner }}" TARGET=x86_64-unknown-linux-gnu ../../../../cargo.sh test -- --skip rtm --skip tbm --skip sse4a
+        STDARCH_TEST_EVERYTHING=1 CHANNEL=release CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUNNER="${{ matrix.cargo_runner }}" TARGET=x86_64-unknown-linux-gnu CG_RUSTFLAGS="-Ainternal_features" ../../../../cargo.sh test -- --skip rtm --skip tbm --skip sse4a
diff --git a/Cargo.lock b/Cargo.lock
index 60df0e60988..7fcb124927a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -12,16 +12,16 @@ dependencies = [
 ]
 
 [[package]]
-name = "autocfg"
-version = "1.1.0"
+name = "bitflags"
+version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
 [[package]]
 name = "bitflags"
-version = "1.3.2"
+version = "2.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+checksum = "b4682ae6287fcf752ecaabbfcc7b6f9b72aa33933dc23a554d853aea8eea8635"
 
 [[package]]
 name = "cc"
@@ -58,12 +58,9 @@ dependencies = [
 
 [[package]]
 name = "fastrand"
-version = "1.9.0"
+version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e51093e27b0797c359783294ca4f0a911c270184cb10f85783b118614a1501be"
-dependencies = [
- "instant",
-]
+checksum = "6999dc1837253364c2ebb0704ba97994bd874e8f195d665c50b7548f6ea92764"
 
 [[package]]
 name = "fm"
@@ -77,7 +74,7 @@ dependencies = [
 [[package]]
 name = "gccjit"
 version = "1.0.0"
-source = "git+https://github.com/antoyo/gccjit.rs#61d8d55c894bd462ee66c096cc31157a44a9f869"
+source = "git+https://github.com/antoyo/gccjit.rs#814eea1a0a098d08a113794225cad301622fd7b4"
 dependencies = [
  "gccjit_sys",
 ]
@@ -85,7 +82,7 @@ dependencies = [
 [[package]]
 name = "gccjit_sys"
 version = "0.0.1"
-source = "git+https://github.com/antoyo/gccjit.rs#61d8d55c894bd462ee66c096cc31157a44a9f869"
+source = "git+https://github.com/antoyo/gccjit.rs#814eea1a0a098d08a113794225cad301622fd7b4"
 dependencies = [
  "libc",
 ]
@@ -105,26 +102,6 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fed44880c466736ef9a5c5b5facefb5ed0785676d0c02d612db14e54f0d84286"
 
-[[package]]
-name = "instant"
-version = "0.1.12"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7a5bbe824c507c5da5956355e86a746d82e0e1464f65d862cc5e71da70e94b2c"
-dependencies = [
- "cfg-if",
-]
-
-[[package]]
-name = "io-lifetimes"
-version = "1.0.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eae7b9aee968036d54dce06cebaefd919e4472e753296daccd6d344e3e2df0c2"
-dependencies = [
- "hermit-abi",
- "libc",
- "windows-sys",
-]
-
 [[package]]
 name = "lang_tester"
 version = "0.3.13"
@@ -149,9 +126,9 @@ checksum = "b4668fb0ea861c1df094127ac5f1da3409a82116a4ba74fca2e58ef927159bb3"
 
 [[package]]
 name = "linux-raw-sys"
-version = "0.3.8"
+version = "0.4.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ef53942eb7bf7ff43a617b3e2c1c4a5ecf5944a7c1bc12d7ee39bbb15e5c1519"
+checksum = "57bcfdad1b858c2db7c38303a6d2ad4dfaf5eb53dfeb0910128b2c26d6158503"
 
 [[package]]
 name = "memchr"
@@ -175,7 +152,7 @@ version = "0.3.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "567664f262709473930a4bf9e51bf2ebf3348f2e748ccc50dea20646858f8f29"
 dependencies = [
- "bitflags",
+ "bitflags 1.3.2",
 ]
 
 [[package]]
@@ -207,13 +184,12 @@ dependencies = [
 
 [[package]]
 name = "rustix"
-version = "0.37.22"
+version = "0.38.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8818fa822adcc98b18fedbb3632a6a33213c070556b5aa7c4c8cc21cff565c4c"
+checksum = "19ed4fa021d81c8392ce04db050a3da9a60299050b7ae1cf482d862b54a7218f"
 dependencies = [
- "bitflags",
+ "bitflags 2.4.0",
  "errno",
- "io-lifetimes",
  "libc",
  "linux-raw-sys",
  "windows-sys",
@@ -236,11 +212,10 @@ checksum = "a507befe795404456341dfab10cef66ead4c041f62b8b11bbb92bffe5d0953e0"
 
 [[package]]
 name = "tempfile"
-version = "3.6.0"
+version = "3.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "31c0432476357e58790aaa47a8efb0c5138f137343f3b5f23bd36a27e3b0a6d6"
+checksum = "dc02fddf48964c42031a0b3fe0428320ecf3a73c401040fc0096f97794310651"
 dependencies = [
- "autocfg",
  "cfg-if",
  "fastrand",
  "redox_syscall",
diff --git a/Cargo.toml b/Cargo.toml
index 81066d9ce1f..3bf629fc662 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -28,6 +28,8 @@ gccjit = { git = "https://github.com/antoyo/gccjit.rs" }
 #gccjit = { path = "../gccjit.rs" }
 
 smallvec = { version = "1.6.1", features = ["union", "may_dangle"] }
+# TODO(antoyo): make tempfile optional.
+tempfile = "3.7.1"
 
 [dev-dependencies]
 lang_tester = "0.3.9"
diff --git a/build_sysroot/Cargo.toml b/build_sysroot/Cargo.toml
index a84f86a8218..dca2ffdc24b 100644
--- a/build_sysroot/Cargo.toml
+++ b/build_sysroot/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["bjorn3 <bjorn3@users.noreply.github.com>"]
 name = "sysroot"
 version = "0.0.0"
+resolver = "2"
 
 [dependencies]
 core = { path = "./sysroot_src/library/core" }
diff --git a/example/alloc_example.rs b/example/alloc_example.rs
index 754e7931412..f1954a30cf8 100644
--- a/example/alloc_example.rs
+++ b/example/alloc_example.rs
@@ -1,5 +1,6 @@
 #![feature(start, core_intrinsics, alloc_error_handler, lang_items)]
 #![no_std]
+#![allow(internal_features)]
 
 extern crate alloc;
 extern crate alloc_system;
diff --git a/example/alloc_system.rs b/example/alloc_system.rs
index 046903fe5ac..e756b347e89 100644
--- a/example/alloc_system.rs
+++ b/example/alloc_system.rs
@@ -10,6 +10,7 @@
 #[cfg(any(target_arch = "x86",
               target_arch = "arm",
               target_arch = "mips",
+              target_arch = "mips32r6",
               target_arch = "powerpc",
               target_arch = "powerpc64"))]
 const MIN_ALIGN: usize = 8;
@@ -17,6 +18,7 @@ const MIN_ALIGN: usize = 8;
               target_arch = "aarch64",
               target_arch = "loongarch64",
               target_arch = "mips64",
+              target_arch = "mips64r6",
               target_arch = "s390x",
               target_arch = "sparc64"))]
 const MIN_ALIGN: usize = 16;
diff --git a/example/arbitrary_self_types_pointers_and_wrappers.rs b/example/arbitrary_self_types_pointers_and_wrappers.rs
index 3af0ba09e0b..b299aa87974 100644
--- a/example/arbitrary_self_types_pointers_and_wrappers.rs
+++ b/example/arbitrary_self_types_pointers_and_wrappers.rs
@@ -2,6 +2,7 @@
 
 #![feature(arbitrary_self_types, unsize, coerce_unsized, dispatch_from_dyn)]
 #![feature(rustc_attrs)]
+#![allow(internal_features)]
 
 use std::{
     ops::{Deref, CoerceUnsized, DispatchFromDyn},
diff --git a/example/mini_core.rs b/example/mini_core.rs
index 0cd7e6047c2..58df29bb625 100644
--- a/example/mini_core.rs
+++ b/example/mini_core.rs
@@ -4,7 +4,7 @@
     thread_local
 )]
 #![no_core]
-#![allow(dead_code)]
+#![allow(dead_code, internal_features)]
 
 #[no_mangle]
 unsafe extern "C" fn _Unwind_Resume() {
diff --git a/example/mini_core_hello_world.rs b/example/mini_core_hello_world.rs
index b93d6859706..c3aea571815 100644
--- a/example/mini_core_hello_world.rs
+++ b/example/mini_core_hello_world.rs
@@ -5,7 +5,7 @@
     extern_types, thread_local
 )]
 #![no_core]
-#![allow(dead_code, non_camel_case_types)]
+#![allow(dead_code, internal_features, non_camel_case_types)]
 
 extern crate mini_core;
 
diff --git a/example/mod_bench.rs b/example/mod_bench.rs
index 5e2e7f25a2c..c60bc7fb724 100644
--- a/example/mod_bench.rs
+++ b/example/mod_bench.rs
@@ -1,5 +1,6 @@
 #![feature(start, core_intrinsics, lang_items)]
 #![no_std]
+#![allow(internal_features)]
 
 #[link(name = "c")]
 extern {}
diff --git a/failing-ui-tests.txt b/failing-ui-tests.txt
index 69f57036b01..fe0df3347bb 100644
--- a/failing-ui-tests.txt
+++ b/failing-ui-tests.txt
@@ -67,3 +67,6 @@ tests/ui/issues/issue-29948.rs
 tests/ui/panic-while-printing.rs
 tests/ui/enum-discriminant/get_discr.rs
 tests/ui/panics/nested_panic_caught.rs
+tests/ui/simd/intrinsic/generic-bswap-byte.rs
+tests/ui/const_prop/ice-issue-111353.rs
+tests/ui/process/println-with-broken-pipe.rs
diff --git a/messages.ftl b/messages.ftl
index 97bc8ef9d1b..2fd0daee3e7 100644
--- a/messages.ftl
+++ b/messages.ftl
@@ -1,63 +1,6 @@
 codegen_gcc_invalid_minimum_alignment =
     invalid minimum global alignment: {$err}
 
-codegen_gcc_invalid_monomorphization_basic_integer =
-    invalid monomorphization of `{$name}` intrinsic: expected basic integer type, found `{$ty}`
-
-codegen_gcc_invalid_monomorphization_expected_signed_unsigned =
-    invalid monomorphization of `{$name}` intrinsic: expected element type `{$elem_ty}` of vector type `{$vec_ty}` to be a signed or unsigned integer type
-
-codegen_gcc_invalid_monomorphization_expected_simd =
-    invalid monomorphization of `{$name}` intrinsic: expected SIMD {$expected_ty} type, found non-SIMD `{$found_ty}`
-
-codegen_gcc_invalid_monomorphization_inserted_type =
-    invalid monomorphization of `{$name}` intrinsic: expected inserted type `{$in_elem}` (element of input `{$in_ty}`), found `{$out_ty}`
-
-codegen_gcc_invalid_monomorphization_invalid_bitmask =
-    invalid monomorphization of `{$name}` intrinsic: invalid bitmask `{$ty}`, expected `u{$expected_int_bits}` or `[u8; {$expected_bytes}]`
-
-codegen_gcc_invalid_monomorphization_invalid_float_vector =
-    invalid monomorphization of `{$name}` intrinsic: unsupported element type `{$elem_ty}` of floating-point vector `{$vec_ty}`
-
-codegen_gcc_invalid_monomorphization_mask_type =
-    invalid monomorphization of `{$name}` intrinsic: mask element type is `{$ty}`, expected `i_`
-
-codegen_gcc_invalid_monomorphization_mismatched_lengths =
-    invalid monomorphization of `{$name}` intrinsic: mismatched lengths: mask length `{$m_len}` != other vector length `{$v_len}`
-
-codegen_gcc_invalid_monomorphization_not_float =
-    invalid monomorphization of `{$name}` intrinsic: `{$ty}` is not a floating-point type
-
-codegen_gcc_invalid_monomorphization_return_element =
-    invalid monomorphization of `{$name}` intrinsic: expected return element type `{$in_elem}` (element of input `{$in_ty}`), found `{$ret_ty}` with element type `{$out_ty}`
-
-codegen_gcc_invalid_monomorphization_return_integer_type =
-    invalid monomorphization of `{$name}` intrinsic: expected return type with integer elements, found `{$ret_ty}` with non-integer `{$out_ty}`
-
-codegen_gcc_invalid_monomorphization_return_length =
-    invalid monomorphization of `{$name}` intrinsic: expected return type of length {$in_len}, found `{$ret_ty}` with length {$out_len}
-
-codegen_gcc_invalid_monomorphization_return_length_input_type =
-    invalid monomorphization of `{$name}` intrinsic: expected return type with length {$in_len} (same as input type `{$in_ty}`), found `{$ret_ty}` with length {$out_len}
-
-codegen_gcc_invalid_monomorphization_return_type =
-    invalid monomorphization of `{$name}` intrinsic: expected return type `{$in_elem}` (element of input `{$in_ty}`), found `{$ret_ty}`
-
-codegen_gcc_invalid_monomorphization_simd_shuffle =
-    invalid monomorphization of `{$name}` intrinsic: simd_shuffle index must be an array of `u32`, got `{$ty}`
-
-codegen_gcc_invalid_monomorphization_unrecognized =
-    invalid monomorphization of `{$name}` intrinsic: unrecognized intrinsic `{$name}`
-
-codegen_gcc_invalid_monomorphization_unsupported_cast =
-    invalid monomorphization of `{$name}` intrinsic: unsupported cast from `{$in_ty}` with element `{$in_elem}` to `{$ret_ty}` with element `{$out_elem}`
-
-codegen_gcc_invalid_monomorphization_unsupported_element =
-    invalid monomorphization of `{$name}` intrinsic: unsupported {$name} from `{$in_ty}` with element `{$elem_ty}` to `{$ret_ty}`
-
-codegen_gcc_invalid_monomorphization_unsupported_operation =
-    invalid monomorphization of `{$name}` intrinsic: unsupported operation on `{$in_ty}` with element `{$in_elem}`
-
 codegen_gcc_lto_not_supported =
     LTO is not supported. You may get a linker error.
 
diff --git a/rust-toolchain b/rust-toolchain
index ebb04d0069c..1b60d708007 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2023-06-19"
+channel = "nightly-2023-08-12"
 components = ["rust-src", "rustc-dev", "llvm-tools-preview"]
diff --git a/src/allocator.rs b/src/allocator.rs
index 38309fa0153..c8c098e2973 100644
--- a/src/allocator.rs
+++ b/src/allocator.rs
@@ -26,8 +26,8 @@ pub(crate) unsafe fn codegen(tcx: TyCtxt<'_>, mods: &mut GccContext, _module_nam
     if kind == AllocatorKind::Default {
         for method in ALLOCATOR_METHODS {
             let mut types = Vec::with_capacity(method.inputs.len());
-            for ty in method.inputs.iter() {
-                match *ty {
+            for input in method.inputs.iter() {
+                match input.ty {
                     AllocatorTy::Layout => {
                         types.push(usize);
                         types.push(usize);
diff --git a/src/base.rs b/src/base.rs
index 82669aa99cf..bf0309fea14 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -6,8 +6,10 @@ use std::time::Instant;
 use gccjit::{
     Context,
     FunctionType,
-    GlobalKind, TargetInfo,
+    GlobalKind,
 };
+#[cfg(feature="master")]
+use gccjit::TargetInfo;
 use rustc_middle::dep_graph;
 use rustc_middle::ty::TyCtxt;
 #[cfg(feature="master")]
@@ -20,6 +22,8 @@ use rustc_codegen_ssa::traits::DebugInfoMethods;
 use rustc_session::config::DebugInfo;
 use rustc_span::Symbol;
 
+#[cfg(not(feature="master"))]
+use crate::TargetInfo;
 use crate::GccContext;
 use crate::builder::Builder;
 use crate::context::CodegenCx;
@@ -144,6 +148,9 @@ pub fn compile_codegen_unit(tcx: TyCtxt<'_>, cgu_name: Symbol, target_info: Arc<
         if env::var("CG_GCCJIT_DUMP_RTL").as_deref() == Ok("1") {
             context.add_command_line_option("-fdump-rtl-vregs");
         }
+        if env::var("CG_GCCJIT_DUMP_RTL_ALL").as_deref() == Ok("1") {
+            context.add_command_line_option("-fdump-rtl-all");
+        }
         if env::var("CG_GCCJIT_DUMP_TREE_ALL").as_deref() == Ok("1") {
             context.add_command_line_option("-fdump-tree-all");
         }
@@ -168,8 +175,8 @@ pub fn compile_codegen_unit(tcx: TyCtxt<'_>, cgu_name: Symbol, target_info: Arc<
             let cx = CodegenCx::new(&context, cgu, tcx, target_info.supports_128bit_int());
 
             let mono_items = cgu.items_in_deterministic_order(tcx);
-            for &(mono_item, (linkage, visibility)) in &mono_items {
-                mono_item.predefine::<Builder<'_, '_, '_>>(&cx, linkage, visibility);
+            for &(mono_item, data) in &mono_items {
+                mono_item.predefine::<Builder<'_, '_, '_>>(&cx, data.linkage, data.visibility);
             }
 
             // ... and now that we have everything pre-defined, fill out those definitions.
diff --git a/src/builder.rs b/src/builder.rs
index 43d0aafbd50..b0feb99e3c6 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -27,7 +27,6 @@ use rustc_codegen_ssa::traits::{
     BaseTypeMethods,
     BuilderMethods,
     ConstMethods,
-    DerivedTypeMethods,
     LayoutTypeMethods,
     HasCodegen,
     OverflowOp,
@@ -248,16 +247,9 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
     }
 
     fn check_store(&mut self, val: RValue<'gcc>, ptr: RValue<'gcc>) -> RValue<'gcc> {
-        let dest_ptr_ty = self.cx.val_ty(ptr).make_pointer(); // TODO(antoyo): make sure make_pointer() is okay here.
         let stored_ty = self.cx.val_ty(val);
         let stored_ptr_ty = self.cx.type_ptr_to(stored_ty);
-
-        if dest_ptr_ty == stored_ptr_ty {
-            ptr
-        }
-        else {
-            self.bitcast(ptr, stored_ptr_ty)
-        }
+        self.bitcast(ptr, stored_ptr_ty)
     }
 
     pub fn current_func(&self) -> Function<'gcc> {
@@ -501,7 +493,7 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
     }
 
     #[cfg(not(feature="master"))]
-    fn invoke(&mut self, typ: Type<'gcc>, fn_attrs: &CodegenFnAttrs, fn_abi: Option<&FnAbi<'tcx, Ty<'tcx>>>, func: RValue<'gcc>, args: &[RValue<'gcc>], then: Block<'gcc>, catch: Block<'gcc>, _funclet: Option<&Funclet>) -> RValue<'gcc> {
+    fn invoke(&mut self, typ: Type<'gcc>, fn_attrs: Option<&CodegenFnAttrs>, fn_abi: Option<&FnAbi<'tcx, Ty<'tcx>>>, func: RValue<'gcc>, args: &[RValue<'gcc>], then: Block<'gcc>, catch: Block<'gcc>, _funclet: Option<&Funclet>) -> RValue<'gcc> {
         let call_site = self.call(typ, fn_attrs, None, func, args, None);
         let condition = self.context.new_rvalue_from_int(self.bool_type, 1);
         self.llbb().end_with_conditional(None, condition, then, catch);
@@ -917,7 +909,9 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
             .add_eval(None, self.context.new_call(None, atomic_store, &[ptr, value, ordering]));
     }
 
-    fn gep(&mut self, _typ: Type<'gcc>, ptr: RValue<'gcc>, indices: &[RValue<'gcc>]) -> RValue<'gcc> {
+    fn gep(&mut self, typ: Type<'gcc>, ptr: RValue<'gcc>, indices: &[RValue<'gcc>]) -> RValue<'gcc> {
+        // NOTE: due to opaque pointers now being used, we need to cast here.
+        let ptr = self.context.new_cast(None, ptr, typ.make_pointer());
         let ptr_type = ptr.get_type();
         let mut pointee_type = ptr.get_type();
         // NOTE: we cannot use array indexing here like in inbounds_gep because array indexing is
diff --git a/src/callee.rs b/src/callee.rs
index 433b2585f82..a96bd66ba79 100644
--- a/src/callee.rs
+++ b/src/callee.rs
@@ -17,8 +17,8 @@ use crate::context::CodegenCx;
 pub fn get_fn<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, instance: Instance<'tcx>) -> Function<'gcc> {
     let tcx = cx.tcx();
 
-    assert!(!instance.substs.has_infer());
-    assert!(!instance.substs.has_escaping_bound_vars());
+    assert!(!instance.args.has_infer());
+    assert!(!instance.args.has_escaping_bound_vars());
 
     let sym = tcx.symbol_name(instance).name;
 
@@ -100,7 +100,7 @@ pub fn get_fn<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, instance: Instance<'tcx>)
             // whether we are sharing generics or not. The important thing here is
             // that the visibility we apply to the declaration is the same one that
             // has been applied to the definition (wherever that definition may be).
-            let is_generic = instance.substs.non_erasable_generics().next().is_some();
+            let is_generic = instance.args.non_erasable_generics().next().is_some();
 
             if is_generic {
                 // This is a monomorphization. Its expected visibility depends
diff --git a/src/common.rs b/src/common.rs
index b62f4676f70..5f54cb16d8e 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -16,6 +16,10 @@ use crate::context::CodegenCx;
 use crate::type_of::LayoutGccExt;
 
 impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
+    pub fn const_ptrcast(&self, val: RValue<'gcc>, ty: Type<'gcc>) -> RValue<'gcc> {
+        self.context.new_cast(None, val, ty)
+    }
+
     pub fn const_bytes(&self, bytes: &[u8]) -> RValue<'gcc> {
         bytes_in_context(self, bytes)
     }
@@ -242,10 +246,6 @@ impl<'gcc, 'tcx> ConstMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
         const_alloc_to_gcc(self, alloc)
     }
 
-    fn const_ptrcast(&self, val: RValue<'gcc>, ty: Type<'gcc>) -> RValue<'gcc> {
-        self.context.new_cast(None, val, ty)
-    }
-
     fn const_bitcast(&self, value: RValue<'gcc>, typ: Type<'gcc>) -> RValue<'gcc> {
         if value.get_type() == self.bool_type.make_pointer() {
             if let Some(pointee) = typ.get_pointee() {
diff --git a/src/context.rs b/src/context.rs
index 08507e19652..88dcafa7370 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -476,7 +476,7 @@ impl<'gcc, 'tcx> LayoutOfHelpers<'tcx> for CodegenCx<'gcc, 'tcx> {
 
     #[inline]
     fn handle_layout_err(&self, err: LayoutError<'tcx>, span: Span, ty: Ty<'tcx>) -> ! {
-        if let LayoutError::SizeOverflow(_) = err {
+        if let LayoutError::SizeOverflow(_) | LayoutError::ReferencesError(_) = err {
             self.sess().emit_fatal(respan(span, err.into_diagnostic()))
         } else {
             span_bug!(span, "failed to get layout for `{}`: {}", ty, err)
diff --git a/src/coverageinfo.rs b/src/coverageinfo.rs
index 872fc2472e2..849e9886ef3 100644
--- a/src/coverageinfo.rs
+++ b/src/coverageinfo.rs
@@ -1,69 +1,11 @@
-use gccjit::RValue;
-use rustc_codegen_ssa::traits::{CoverageInfoBuilderMethods, CoverageInfoMethods};
-use rustc_hir::def_id::DefId;
-use rustc_middle::mir::coverage::{
-    CodeRegion,
-    CounterValueReference,
-    ExpressionOperandId,
-    InjectedExpressionId,
-    Op,
-};
+use rustc_codegen_ssa::traits::CoverageInfoBuilderMethods;
+use rustc_middle::mir::Coverage;
 use rustc_middle::ty::Instance;
 
 use crate::builder::Builder;
-use crate::context::CodegenCx;
 
 impl<'a, 'gcc, 'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
-    fn set_function_source_hash(
-        &mut self,
-        _instance: Instance<'tcx>,
-        _function_source_hash: u64,
-    ) -> bool {
-        unimplemented!();
-    }
-
-    fn add_coverage_counter(&mut self, _instance: Instance<'tcx>, _id: CounterValueReference, _region: CodeRegion) -> bool {
-        // TODO(antoyo)
-        false
-    }
-
-    fn add_coverage_counter_expression(&mut self, _instance: Instance<'tcx>, _id: InjectedExpressionId, _lhs: ExpressionOperandId, _op: Op, _rhs: ExpressionOperandId, _region: Option<CodeRegion>) -> bool {
-        // TODO(antoyo)
-        false
-    }
-
-    fn add_coverage_unreachable(&mut self, _instance: Instance<'tcx>, _region: CodeRegion) -> bool {
+    fn add_coverage(&mut self, _instance: Instance<'tcx>, _coverage: &Coverage) {
         // TODO(antoyo)
-        false
-    }
-}
-
-impl<'gcc, 'tcx> CoverageInfoMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
-    fn coverageinfo_finalize(&self) {
-        // TODO(antoyo)
-    }
-
-    fn get_pgo_func_name_var(&self, _instance: Instance<'tcx>) -> RValue<'gcc> {
-        unimplemented!();
-    }
-
-    /// Functions with MIR-based coverage are normally codegenned _only_ if
-    /// called. LLVM coverage tools typically expect every function to be
-    /// defined (even if unused), with at least one call to LLVM intrinsic
-    /// `instrprof.increment`.
-    ///
-    /// Codegen a small function that will never be called, with one counter
-    /// that will never be incremented.
-    ///
-    /// For used/called functions, the coverageinfo was already added to the
-    /// `function_coverage_map` (keyed by function `Instance`) during codegen.
-    /// But in this case, since the unused function was _not_ previously
-    /// codegenned, collect the coverage `CodeRegion`s from the MIR and add
-    /// them. The first `CodeRegion` is used to add a single counter, with the
-    /// same counter ID used in the injected `instrprof.increment` intrinsic
-    /// call. Since the function is never called, all other `CodeRegion`s can be
-    /// added as `unreachable_region`s.
-    fn define_unused_fn(&self, _def_id: DefId) {
-        unimplemented!();
     }
 }
diff --git a/src/errors.rs b/src/errors.rs
index 9305bd1e043..693367192b1 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -1,7 +1,6 @@
 use rustc_errors::{DiagnosticArgValue, IntoDiagnosticArg};
 use rustc_macros::Diagnostic;
-use rustc_middle::ty::Ty;
-use rustc_span::{Span, Symbol};
+use rustc_span::Span;
 use std::borrow::Cow;
 
 struct ExitCode(Option<i32>);
@@ -16,201 +15,6 @@ impl IntoDiagnosticArg for ExitCode {
     }
 }
 
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_basic_integer, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationBasicInteger<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub ty: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_invalid_float_vector, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationInvalidFloatVector<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub elem_ty: &'a str,
-    pub vec_ty: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_not_float, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationNotFloat<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub ty: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_unrecognized, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationUnrecognized {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_expected_signed_unsigned, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationExpectedSignedUnsigned<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub elem_ty: Ty<'a>,
-    pub vec_ty: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_unsupported_element, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationUnsupportedElement<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub in_ty: Ty<'a>,
-    pub elem_ty: Ty<'a>,
-    pub ret_ty: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_invalid_bitmask, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationInvalidBitmask<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub ty: Ty<'a>,
-    pub expected_int_bits: u64,
-    pub expected_bytes: u64,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_simd_shuffle, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationSimdShuffle<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub ty: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_expected_simd, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationExpectedSimd<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub position: &'a str,
-    pub found_ty: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_mask_type, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationMaskType<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub ty: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_return_length, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationReturnLength<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub in_len: u64,
-    pub ret_ty: Ty<'a>,
-    pub out_len: u64,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_return_length_input_type, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationReturnLengthInputType<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub in_len: u64,
-    pub in_ty: Ty<'a>,
-    pub ret_ty: Ty<'a>,
-    pub out_len: u64,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_return_element, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationReturnElement<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub in_elem: Ty<'a>,
-    pub in_ty: Ty<'a>,
-    pub ret_ty: Ty<'a>,
-    pub out_ty: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_return_type, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationReturnType<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub in_elem: Ty<'a>,
-    pub in_ty: Ty<'a>,
-    pub ret_ty: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_inserted_type, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationInsertedType<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub in_elem: Ty<'a>,
-    pub in_ty: Ty<'a>,
-    pub out_ty: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_return_integer_type, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationReturnIntegerType<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub ret_ty: Ty<'a>,
-    pub out_ty: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_mismatched_lengths, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationMismatchedLengths {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub m_len: u64,
-    pub v_len: u64,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_unsupported_cast, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationUnsupportedCast<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub in_ty: Ty<'a>,
-    pub in_elem: Ty<'a>,
-    pub ret_ty: Ty<'a>,
-    pub out_elem: Ty<'a>,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_gcc_invalid_monomorphization_unsupported_operation, code = "E0511")]
-pub(crate) struct InvalidMonomorphizationUnsupportedOperation<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub name: Symbol,
-    pub in_ty: Ty<'a>,
-    pub in_elem: Ty<'a>,
-}
-
 #[derive(Diagnostic)]
 #[diag(codegen_gcc_lto_not_supported)]
 pub(crate) struct LTONotSupported;
diff --git a/src/int.rs b/src/int.rs
index 0cf1204791d..2a6b1d17a3e 100644
--- a/src/int.rs
+++ b/src/int.rs
@@ -546,7 +546,12 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
     }
 
     pub fn gcc_uint(&self, typ: Type<'gcc>, int: u64) -> RValue<'gcc> {
-        if self.is_native_int_type_or_bool(typ) {
+        if typ.is_u128(self) {
+            // FIXME(antoyo): libgccjit cannot create 128-bit values yet.
+            let num = self.context.new_rvalue_from_long(self.u64_type, int as i64);
+            self.gcc_int_cast(num, typ)
+        }
+        else if self.is_native_int_type_or_bool(typ) {
             self.context.new_rvalue_from_long(typ, u64::try_from(int).expect("u64::try_from") as i64)
         }
         else {
@@ -572,6 +577,7 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
             }
         }
         else if typ.is_i128(self) {
+            // FIXME(antoyo): libgccjit cannot create 128-bit values yet.
             let num = self.context.new_rvalue_from_long(self.u64_type, num as u64 as i64);
             self.gcc_int_cast(num, typ)
         }
diff --git a/src/intrinsic/mod.rs b/src/intrinsic/mod.rs
index a31fee39918..fab5cba6476 100644
--- a/src/intrinsic/mod.rs
+++ b/src/intrinsic/mod.rs
@@ -10,9 +10,10 @@ use rustc_codegen_ssa::base::wants_msvc_seh;
 use rustc_codegen_ssa::common::IntPredicate;
 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
 use rustc_codegen_ssa::mir::place::PlaceRef;
-use rustc_codegen_ssa::traits::{ArgAbiMethods, BaseTypeMethods, BuilderMethods, ConstMethods, IntrinsicCallMethods};
+use rustc_codegen_ssa::traits::{ArgAbiMethods, BuilderMethods, ConstMethods, IntrinsicCallMethods};
 #[cfg(feature="master")]
-use rustc_codegen_ssa::traits::{DerivedTypeMethods, MiscMethods};
+use rustc_codegen_ssa::traits::{BaseTypeMethods, MiscMethods};
+use rustc_codegen_ssa::errors::InvalidMonomorphization;
 use rustc_middle::bug;
 use rustc_middle::ty::{self, Instance, Ty};
 use rustc_middle::ty::layout::LayoutOf;
@@ -31,7 +32,6 @@ use crate::abi::FnAbiGccExt;
 use crate::builder::Builder;
 use crate::common::{SignType, TypeReflection};
 use crate::context::CodegenCx;
-use crate::errors::InvalidMonomorphizationBasicInteger;
 use crate::type_of::LayoutGccExt;
 use crate::intrinsic::simd::generic_simd_intrinsic;
 
@@ -92,8 +92,8 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
         let tcx = self.tcx;
         let callee_ty = instance.ty(tcx, ty::ParamEnv::reveal_all());
 
-        let (def_id, substs) = match *callee_ty.kind() {
-            ty::FnDef(def_id, substs) => (def_id, substs),
+        let (def_id, fn_args) = match *callee_ty.kind() {
+            ty::FnDef(def_id, fn_args) => (def_id, fn_args),
             _ => bug!("expected fn item type, found {}", callee_ty),
         };
 
@@ -142,7 +142,7 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
                 }
 
                 sym::volatile_load | sym::unaligned_volatile_load => {
-                    let tp_ty = substs.type_at(0);
+                    let tp_ty = fn_args.type_at(0);
                     let mut ptr = args[0].immediate();
                     if let PassMode::Cast(ty, _) = &fn_abi.ret.mode {
                         ptr = self.pointercast(ptr, self.type_ptr_to(ty.gcc_type(self)));
@@ -256,7 +256,7 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
                                 _ => bug!(),
                             },
                             None => {
-                                tcx.sess.emit_err(InvalidMonomorphizationBasicInteger { span, name, ty });
+                                tcx.sess.emit_err(InvalidMonomorphization::BasicIntegerType { span, name, ty });
                                 return;
                             }
                         }
@@ -264,7 +264,7 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
 
                 sym::raw_eq => {
                     use rustc_target::abi::Abi::*;
-                    let tp_ty = substs.type_at(0);
+                    let tp_ty = fn_args.type_at(0);
                     let layout = self.layout_of(tp_ty).layout;
                     let _use_integer_compare = match layout.abi() {
                         Scalar(_) | ScalarPair(_, _) => true,
@@ -302,6 +302,21 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
                     }
                 }
 
+                sym::compare_bytes => {
+                    let a = args[0].immediate();
+                    let b = args[1].immediate();
+                    let n = args[2].immediate();
+
+                    let void_ptr_type = self.context.new_type::<*const ()>();
+                    let a_ptr = self.bitcast(a, void_ptr_type);
+                    let b_ptr = self.bitcast(b, void_ptr_type);
+
+                    // Here we assume that the `memcmp` provided by the target is a NOP for size 0.
+                    let builtin = self.context.get_builtin_function("memcmp");
+                    let cmp = self.context.new_call(None, builtin, &[a_ptr, b_ptr, n]);
+                    self.sext(cmp, self.type_ix(32))
+                }
+
                 sym::black_box => {
                     args[0].val.store(self, result);
 
@@ -1147,19 +1162,19 @@ fn get_rust_try_fn<'a, 'gcc, 'tcx>(cx: &'a CodegenCx<'gcc, 'tcx>, codegen: &mut
 
     // Define the type up front for the signature of the rust_try function.
     let tcx = cx.tcx;
-    let i8p = tcx.mk_mut_ptr(tcx.types.i8);
+    let i8p = Ty::new_mut_ptr(tcx,tcx.types.i8);
     // `unsafe fn(*mut i8) -> ()`
-    let try_fn_ty = tcx.mk_fn_ptr(ty::Binder::dummy(tcx.mk_fn_sig(
+    let try_fn_ty = Ty::new_fn_ptr(tcx,ty::Binder::dummy(tcx.mk_fn_sig(
         iter::once(i8p),
-        tcx.mk_unit(),
+        Ty::new_unit(tcx,),
         false,
         rustc_hir::Unsafety::Unsafe,
         Abi::Rust,
     )));
     // `unsafe fn(*mut i8, *mut i8) -> ()`
-    let catch_fn_ty = tcx.mk_fn_ptr(ty::Binder::dummy(tcx.mk_fn_sig(
+    let catch_fn_ty = Ty::new_fn_ptr(tcx,ty::Binder::dummy(tcx.mk_fn_sig(
         [i8p, i8p].iter().cloned(),
-        tcx.mk_unit(),
+        Ty::new_unit(tcx,),
         false,
         rustc_hir::Unsafety::Unsafe,
         Abi::Rust,
diff --git a/src/intrinsic/simd.rs b/src/intrinsic/simd.rs
index 9115cf97119..85d3e7234a0 100644
--- a/src/intrinsic/simd.rs
+++ b/src/intrinsic/simd.rs
@@ -1,11 +1,11 @@
-#[cfg(feature="master")]
-use gccjit::{ComparisonOp, UnaryOp};
 use gccjit::ToRValue;
 use gccjit::{BinaryOp, RValue, Type};
+#[cfg(feature = "master")]
+use gccjit::{ComparisonOp, UnaryOp};
 
 use rustc_codegen_ssa::base::compare_simd_types;
 use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
-#[cfg(feature="master")]
+#[cfg(feature = "master")]
 use rustc_codegen_ssa::errors::ExpectedPointerMutability;
 use rustc_codegen_ssa::errors::InvalidMonomorphization;
 use rustc_codegen_ssa::mir::operand::OperandRef;
@@ -19,21 +19,8 @@ use rustc_span::{sym, Span, Symbol};
 use rustc_target::abi::Align;
 
 use crate::builder::Builder;
-#[cfg(feature="master")]
+#[cfg(feature = "master")]
 use crate::context::CodegenCx;
-#[cfg(feature="master")]
-use crate::errors::{InvalidMonomorphizationExpectedSignedUnsigned, InvalidMonomorphizationInsertedType};
-use crate::errors::{
-    InvalidMonomorphizationExpectedSimd,
-    InvalidMonomorphizationInvalidBitmask,
-    InvalidMonomorphizationInvalidFloatVector, InvalidMonomorphizationMaskType,
-    InvalidMonomorphizationMismatchedLengths, InvalidMonomorphizationNotFloat,
-    InvalidMonomorphizationReturnElement, InvalidMonomorphizationReturnIntegerType,
-    InvalidMonomorphizationReturnLength, InvalidMonomorphizationReturnLengthInputType,
-    InvalidMonomorphizationReturnType, InvalidMonomorphizationSimdShuffle,
-    InvalidMonomorphizationUnrecognized, InvalidMonomorphizationUnsupportedElement,
-    InvalidMonomorphizationUnsupportedOperation,
-};
 
 pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
     bx: &mut Builder<'a, 'gcc, 'tcx>,
@@ -59,16 +46,8 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         };
     }
     macro_rules! require_simd {
-        ($ty: expr, $position: expr) => {
-            require!(
-                $ty.is_simd(),
-                InvalidMonomorphizationExpectedSimd {
-                    span,
-                    name,
-                    position: $position,
-                    found_ty: $ty
-                }
-            )
+        ($ty: expr, $diag: expr) => {
+            require!($ty.is_simd(), $diag)
         };
     }
 
@@ -78,7 +57,10 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
     let arg_tys = sig.inputs();
 
     if name == sym::simd_select_bitmask {
-        require_simd!(arg_tys[1], "argument");
+        require_simd!(
+            arg_tys[1],
+            InvalidMonomorphization::SimdArgument { span, name, ty: arg_tys[1] }
+        );
         let (len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
 
         let expected_int_bits = (len.max(8) - 1).next_power_of_two();
@@ -99,10 +81,10 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                 let ptr = bx.pointercast(place.llval, bx.cx.type_ptr_to(int_ty));
                 bx.load(int_ty, ptr, Align::ONE)
             }
-            _ => return_error!(InvalidMonomorphizationInvalidBitmask {
+            _ => return_error!(InvalidMonomorphization::InvalidBitmask {
                 span,
                 name,
-                ty: mask_ty,
+                mask_ty,
                 expected_int_bits,
                 expected_bytes
             }),
@@ -116,7 +98,8 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         // NOTE: since the arguments can be vectors of floats, make sure the mask is a vector of
         // integer.
         let mask_element_type = bx.type_ix(arg1_element_type.get_size() as u64 * 8);
-        let vector_mask_type = bx.context.new_vector_type(mask_element_type, arg1_vector_type.get_num_units() as u64);
+        let vector_mask_type =
+            bx.context.new_vector_type(mask_element_type, arg1_vector_type.get_num_units() as u64);
 
         let mut elements = vec![];
         let one = bx.context.new_rvalue_one(mask.get_type());
@@ -131,7 +114,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
     }
 
     // every intrinsic below takes a SIMD vector as its first argument
-    require_simd!(arg_tys[0], "input");
+    require_simd!(arg_tys[0], InvalidMonomorphization::SimdInput { span, name, ty: arg_tys[0] });
     let in_ty = arg_tys[0];
 
     let comparison = match name {
@@ -146,12 +129,12 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
 
     let (in_len, in_elem) = arg_tys[0].simd_size_and_type(bx.tcx());
     if let Some(cmp_op) = comparison {
-        require_simd!(ret_ty, "return");
+        require_simd!(ret_ty, InvalidMonomorphization::SimdReturn { span, name, ty: ret_ty });
 
         let (out_len, out_ty) = ret_ty.simd_size_and_type(bx.tcx());
         require!(
             in_len == out_len,
-            InvalidMonomorphizationReturnLengthInputType {
+            InvalidMonomorphization::ReturnLengthInputType {
                 span,
                 name,
                 in_len,
@@ -162,7 +145,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         );
         require!(
             bx.type_kind(bx.element_type(llret_ty)) == TypeKind::Integer,
-            InvalidMonomorphizationReturnIntegerType { span, name, ret_ty, out_ty }
+            InvalidMonomorphization::ReturnIntegerType { span, name, ret_ty, out_ty }
         );
 
         let arg1 = args[0].immediate();
@@ -170,48 +153,34 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         // compare them as equal, so bitcast.
         // FIXME(antoyo): allow comparing vector types as equal in libgccjit.
         let arg2 = bx.context.new_bitcast(None, args[1].immediate(), arg1.get_type());
-        return Ok(compare_simd_types(
-            bx,
-            arg1,
-            arg2,
-            in_elem,
-            llret_ty,
-            cmp_op,
-        ));
+        return Ok(compare_simd_types(bx, arg1, arg2, in_elem, llret_ty, cmp_op));
     }
 
-    if let Some(stripped) = name.as_str().strip_prefix("simd_shuffle") {
-        let n: u64 = if stripped.is_empty() {
-            // Make sure this is actually an array, since typeck only checks the length-suffixed
-            // version of this intrinsic.
-            match args[2].layout.ty.kind() {
-                ty::Array(ty, len) if matches!(ty.kind(), ty::Uint(ty::UintTy::U32)) => {
-                    len.try_eval_target_usize(bx.cx.tcx, ty::ParamEnv::reveal_all()).unwrap_or_else(
-                        || span_bug!(span, "could not evaluate shuffle index array length"),
-                    )
-                }
-                _ => return_error!(InvalidMonomorphizationSimdShuffle {
-                    span,
-                    name,
-                    ty: args[2].layout.ty
-                }),
+    if name == sym::simd_shuffle {
+        // Make sure this is actually an array, since typeck only checks the length-suffixed
+        // version of this intrinsic.
+        let n: u64 = match args[2].layout.ty.kind() {
+            ty::Array(ty, len) if matches!(ty.kind(), ty::Uint(ty::UintTy::U32)) => {
+                len.try_eval_target_usize(bx.cx.tcx, ty::ParamEnv::reveal_all()).unwrap_or_else(
+                    || span_bug!(span, "could not evaluate shuffle index array length"),
+                )
             }
-        } else {
-            stripped.parse().unwrap_or_else(|_| {
-                span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?")
-            })
+            _ => return_error!(InvalidMonomorphization::SimdShuffle {
+                span,
+                name,
+                ty: args[2].layout.ty
+            }),
         };
-
-        require_simd!(ret_ty, "return");
+        require_simd!(ret_ty, InvalidMonomorphization::SimdReturn { span, name, ty: ret_ty });
 
         let (out_len, out_ty) = ret_ty.simd_size_and_type(bx.tcx());
         require!(
             out_len == n,
-            InvalidMonomorphizationReturnLength { span, name, in_len: n, ret_ty, out_len }
+            InvalidMonomorphization::ReturnLength { span, name, in_len: n, ret_ty, out_len }
         );
         require!(
             in_elem == out_ty,
-            InvalidMonomorphizationReturnElement { span, name, in_elem, in_ty, ret_ty, out_ty }
+            InvalidMonomorphization::ReturnElement { span, name, in_elem, in_ty, ret_ty, out_ty }
         );
 
         let vector = args[2].immediate();
@@ -223,7 +192,13 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
     if name == sym::simd_insert {
         require!(
             in_elem == arg_tys[2],
-            InvalidMonomorphizationInsertedType { span, name, in_elem, in_ty, out_ty: arg_tys[2] }
+            InvalidMonomorphization::InsertedType {
+                span,
+                name,
+                in_elem,
+                in_ty,
+                out_ty: arg_tys[2]
+            }
         );
         let vector = args[0].immediate();
         let index = args[1].immediate();
@@ -240,7 +215,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
     if name == sym::simd_extract {
         require!(
             ret_ty == in_elem,
-            InvalidMonomorphizationReturnType { span, name, in_elem, in_ty, ret_ty }
+            InvalidMonomorphization::ReturnType { span, name, in_elem, in_ty, ret_ty }
         );
         let vector = args[0].immediate();
         return Ok(bx.context.new_vector_access(None, vector, args[1].immediate()).to_rvalue());
@@ -249,26 +224,29 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
     if name == sym::simd_select {
         let m_elem_ty = in_elem;
         let m_len = in_len;
-        require_simd!(arg_tys[1], "argument");
+        require_simd!(
+            arg_tys[1],
+            InvalidMonomorphization::SimdArgument { span, name, ty: arg_tys[1] }
+        );
         let (v_len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
         require!(
             m_len == v_len,
-            InvalidMonomorphizationMismatchedLengths { span, name, m_len, v_len }
+            InvalidMonomorphization::MismatchedLengths { span, name, m_len, v_len }
         );
         match m_elem_ty.kind() {
             ty::Int(_) => {}
-            _ => return_error!(InvalidMonomorphizationMaskType { span, name, ty: m_elem_ty }),
+            _ => return_error!(InvalidMonomorphization::MaskType { span, name, ty: m_elem_ty }),
         }
         return Ok(bx.vector_select(args[0].immediate(), args[1].immediate(), args[2].immediate()));
     }
 
-    #[cfg(feature="master")]
+    #[cfg(feature = "master")]
     if name == sym::simd_cast || name == sym::simd_as {
-        require_simd!(ret_ty, "return");
+        require_simd!(ret_ty, InvalidMonomorphization::SimdReturn { span, name, ty: ret_ty });
         let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
         require!(
             in_len == out_len,
-            InvalidMonomorphizationReturnLengthInputType {
+            InvalidMonomorphization::ReturnLengthInputType {
                 span,
                 name,
                 in_len,
@@ -288,19 +266,17 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
             Unsupported,
         }
 
-        let in_style =
-            match in_elem.kind() {
-                ty::Int(_) | ty::Uint(_) => Style::Int,
-                ty::Float(_) => Style::Float,
-                 _ => Style::Unsupported,
-            };
+        let in_style = match in_elem.kind() {
+            ty::Int(_) | ty::Uint(_) => Style::Int,
+            ty::Float(_) => Style::Float,
+            _ => Style::Unsupported,
+        };
 
-        let out_style =
-            match out_elem.kind() {
-                ty::Int(_) | ty::Uint(_) => Style::Int,
-                ty::Float(_) => Style::Float,
-                 _ => Style::Unsupported,
-            };
+        let out_style = match out_elem.kind() {
+            ty::Int(_) | ty::Uint(_) => Style::Int,
+            ty::Float(_) => Style::Float,
+            _ => Style::Unsupported,
+        };
 
         match (in_style, out_style) {
             (Style::Unsupported, Style::Unsupported) => {
@@ -315,7 +291,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                         out_elem
                     }
                 );
-            },
+            }
             _ => return Ok(bx.context.convert_vector(None, args[0].immediate(), llret_ty)),
         }
     }
@@ -329,7 +305,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                     })*
                     _ => {},
                 }
-                return_error!(InvalidMonomorphizationUnsupportedOperation { span, name, in_ty, in_elem })
+                return_error!(InvalidMonomorphization::UnsupportedOperation { span, name, in_ty, in_elem })
             })*
         }
     }
@@ -363,10 +339,13 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
 
         let mut shift = 0;
         for i in 0..in_len {
-            let elem = bx.extract_element(vector, bx.context.new_rvalue_from_int(bx.int_type, i as i32));
+            let elem =
+                bx.extract_element(vector, bx.context.new_rvalue_from_int(bx.int_type, i as i32));
             let shifted = elem >> sign_shift;
             let masked = shifted & one;
-            result = result | (bx.context.new_cast(None, masked, result_type) << bx.context.new_rvalue_from_int(result_type, shift));
+            result = result
+                | (bx.context.new_cast(None, masked, result_type)
+                    << bx.context.new_rvalue_from_int(result_type, shift));
             shift += 1;
         }
 
@@ -415,46 +394,50 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                 return Err(());
             }};
         }
-        let (elem_ty_str, elem_ty) =
-            if let ty::Float(f) = in_elem.kind() {
-                let elem_ty = bx.cx.type_float_from_ty(*f);
-                match f.bit_width() {
-                    32 => ("f", elem_ty),
-                    64 => ("", elem_ty),
-                    _ => {
-                        return_error!(InvalidMonomorphizationInvalidFloatVector { span, name, elem_ty: f.name_str(), vec_ty: in_ty });
-                    }
+        let (elem_ty_str, elem_ty) = if let ty::Float(f) = in_elem.kind() {
+            let elem_ty = bx.cx.type_float_from_ty(*f);
+            match f.bit_width() {
+                32 => ("f", elem_ty),
+                64 => ("", elem_ty),
+                _ => {
+                    return_error!(InvalidMonomorphization::FloatingPointVector {
+                        span,
+                        name,
+                        f_ty: *f,
+                        in_ty
+                    });
                 }
             }
-            else {
-                return_error!(InvalidMonomorphizationNotFloat { span, name, ty: in_ty });
-            };
+        } else {
+            return_error!(InvalidMonomorphization::FloatingPointType { span, name, in_ty });
+        };
 
         let vec_ty = bx.cx.type_vector(elem_ty, in_len);
 
-        let intr_name =
-            match name {
-                sym::simd_ceil => "ceil",
-                sym::simd_fabs => "fabs", // TODO(antoyo): pand with 170141183420855150465331762880109871103
-                sym::simd_fcos => "cos",
-                sym::simd_fexp2 => "exp2",
-                sym::simd_fexp => "exp",
-                sym::simd_flog10 => "log10",
-                sym::simd_flog2 => "log2",
-                sym::simd_flog => "log",
-                sym::simd_floor => "floor",
-                sym::simd_fma => "fma",
-                sym::simd_fpowi => "__builtin_powi",
-                sym::simd_fpow => "pow",
-                sym::simd_fsin => "sin",
-                sym::simd_fsqrt => "sqrt",
-                sym::simd_round => "round",
-                sym::simd_trunc => "trunc",
-                _ => return_error!(InvalidMonomorphizationUnrecognized { span, name })
-            };
+        let intr_name = match name {
+            sym::simd_ceil => "ceil",
+            sym::simd_fabs => "fabs", // TODO(antoyo): pand with 170141183420855150465331762880109871103
+            sym::simd_fcos => "cos",
+            sym::simd_fexp2 => "exp2",
+            sym::simd_fexp => "exp",
+            sym::simd_flog10 => "log10",
+            sym::simd_flog2 => "log2",
+            sym::simd_flog => "log",
+            sym::simd_floor => "floor",
+            sym::simd_fma => "fma",
+            sym::simd_fpowi => "__builtin_powi",
+            sym::simd_fpow => "pow",
+            sym::simd_fsin => "sin",
+            sym::simd_fsqrt => "sqrt",
+            sym::simd_round => "round",
+            sym::simd_trunc => "trunc",
+            _ => return_error!(InvalidMonomorphization::UnrecognizedIntrinsic { span, name }),
+        };
         let builtin_name = format!("{}{}", intr_name, elem_ty_str);
         let funcs = bx.cx.functions.borrow();
-        let function = funcs.get(&builtin_name).unwrap_or_else(|| panic!("unable to find builtin function {}", builtin_name));
+        let function = funcs
+            .get(&builtin_name)
+            .unwrap_or_else(|| panic!("unable to find builtin function {}", builtin_name));
 
         // TODO(antoyo): add platform-specific behavior here for architectures that have these
         // intrinsics as instructions (for instance, gpus)
@@ -500,8 +483,12 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         return simd_simple_float_intrinsic(name, in_elem, in_ty, in_len, bx, span, args);
     }
 
-    #[cfg(feature="master")]
-    fn vector_ty<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, elem_ty: Ty<'tcx>, vec_len: u64) -> Type<'gcc> {
+    #[cfg(feature = "master")]
+    fn vector_ty<'gcc, 'tcx>(
+        cx: &CodegenCx<'gcc, 'tcx>,
+        elem_ty: Ty<'tcx>,
+        vec_len: u64,
+    ) -> Type<'gcc> {
         // FIXME: use cx.layout_of(ty).llvm_type() ?
         let elem_ty = match *elem_ty.kind() {
             ty::Int(v) => cx.type_int_from_ty(v),
@@ -512,15 +499,22 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         cx.type_vector(elem_ty, vec_len)
     }
 
-    #[cfg(feature="master")]
-    fn gather<'a, 'gcc, 'tcx>(default: RValue<'gcc>, pointers: RValue<'gcc>, mask: RValue<'gcc>, pointer_count: usize, bx: &mut Builder<'a, 'gcc, 'tcx>, in_len: u64, underlying_ty: Ty<'tcx>, invert: bool) -> RValue<'gcc> {
-        let vector_type =
-            if pointer_count > 1 {
-                bx.context.new_vector_type(bx.usize_type, in_len)
-            }
-            else {
-                vector_ty(bx, underlying_ty, in_len)
-            };
+    #[cfg(feature = "master")]
+    fn gather<'a, 'gcc, 'tcx>(
+        default: RValue<'gcc>,
+        pointers: RValue<'gcc>,
+        mask: RValue<'gcc>,
+        pointer_count: usize,
+        bx: &mut Builder<'a, 'gcc, 'tcx>,
+        in_len: u64,
+        underlying_ty: Ty<'tcx>,
+        invert: bool,
+    ) -> RValue<'gcc> {
+        let vector_type = if pointer_count > 1 {
+            bx.context.new_vector_type(bx.usize_type, in_len)
+        } else {
+            vector_ty(bx, underlying_ty, in_len)
+        };
         let elem_type = vector_type.dyncast_vector().expect("vector type").get_element_type();
 
         let mut values = vec![];
@@ -551,13 +545,12 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
 
         if invert {
             bx.shuffle_vector(vector, default, mask)
-        }
-        else {
+        } else {
             bx.shuffle_vector(default, vector, mask)
         }
     }
 
-    #[cfg(feature="master")]
+    #[cfg(feature = "master")]
     if name == sym::simd_gather {
         // simd_gather(values: <N x T>, pointers: <N x *_ T>,
         //             mask: <N x i{M}>) -> <N x T>
@@ -566,10 +559,16 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         // * M: any integer width is supported, will be truncated to i1
 
         // All types must be simd vector types
-        require_simd!(in_ty, "first");
-        require_simd!(arg_tys[1], "second");
-        require_simd!(arg_tys[2], "third");
-        require_simd!(ret_ty, "return");
+        require_simd!(in_ty, InvalidMonomorphization::SimdFirst { span, name, ty: in_ty });
+        require_simd!(
+            arg_tys[1],
+            InvalidMonomorphization::SimdSecond { span, name, ty: arg_tys[1] }
+        );
+        require_simd!(
+            arg_tys[2],
+            InvalidMonomorphization::SimdThird { span, name, ty: arg_tys[2] }
+        );
+        require_simd!(ret_ty, InvalidMonomorphization::SimdReturn { span, name, ty: ret_ty });
 
         // Of the same length:
         let (out_len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
@@ -662,10 +661,19 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
             }
         }
 
-        return Ok(gather(args[0].immediate(), args[1].immediate(), args[2].immediate(), pointer_count, bx, in_len, underlying_ty, false));
+        return Ok(gather(
+            args[0].immediate(),
+            args[1].immediate(),
+            args[2].immediate(),
+            pointer_count,
+            bx,
+            in_len,
+            underlying_ty,
+            false,
+        ));
     }
 
-    #[cfg(feature="master")]
+    #[cfg(feature = "master")]
     if name == sym::simd_scatter {
         // simd_scatter(values: <N x T>, pointers: <N x *mut T>,
         //             mask: <N x i{M}>) -> ()
@@ -674,9 +682,15 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         // * M: any integer width is supported, will be truncated to i1
 
         // All types must be simd vector types
-        require_simd!(in_ty, "first");
-        require_simd!(arg_tys[1], "second");
-        require_simd!(arg_tys[2], "third");
+        require_simd!(in_ty, InvalidMonomorphization::SimdFirst { span, name, ty: in_ty });
+        require_simd!(
+            arg_tys[1],
+            InvalidMonomorphization::SimdSecond { span, name, ty: arg_tys[1] }
+        );
+        require_simd!(
+            arg_tys[2],
+            InvalidMonomorphization::SimdThird { span, name, ty: arg_tys[2] }
+        );
 
         // Of the same length:
         let (element_len1, _) = arg_tys[1].simd_size_and_type(bx.tcx());
@@ -765,17 +779,24 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
             }
         }
 
-        let result = gather(args[0].immediate(), args[1].immediate(), args[2].immediate(), pointer_count, bx, in_len, underlying_ty, true);
+        let result = gather(
+            args[0].immediate(),
+            args[1].immediate(),
+            args[2].immediate(),
+            pointer_count,
+            bx,
+            in_len,
+            underlying_ty,
+            true,
+        );
 
         let pointers = args[1].immediate();
 
-        let vector_type =
-            if pointer_count > 1 {
-                bx.context.new_vector_type(bx.usize_type, in_len)
-            }
-            else {
-                vector_ty(bx, underlying_ty, in_len)
-            };
+        let vector_type = if pointer_count > 1 {
+            bx.context.new_vector_type(bx.usize_type, in_len)
+        } else {
+            vector_ty(bx, underlying_ty, in_len)
+        };
         let elem_type = vector_type.dyncast_vector().expect("vector type").get_element_type();
 
         for i in 0..in_len {
@@ -815,7 +836,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                     })*
                     _ => {},
                 }
-                return_error!(InvalidMonomorphizationUnsupportedOperation { span, name, in_ty, in_elem })
+                return_error!(InvalidMonomorphization::UnsupportedOperation { span, name, in_ty, in_elem })
             })*
         }
     }
@@ -830,91 +851,97 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         let rhs = args[1].immediate();
         let is_add = name == sym::simd_saturating_add;
         let ptr_bits = bx.tcx().data_layout.pointer_size.bits() as _;
-        let (signed, elem_width, elem_ty) =
-            match *in_elem.kind() {
-                ty::Int(i) => (true, i.bit_width().unwrap_or(ptr_bits) / 8, bx.cx.type_int_from_ty(i)),
-                ty::Uint(i) => (false, i.bit_width().unwrap_or(ptr_bits) / 8, bx.cx.type_uint_from_ty(i)),
-                _ => {
-                return_error!(InvalidMonomorphizationExpectedSignedUnsigned {
+        let (signed, elem_width, elem_ty) = match *in_elem.kind() {
+            ty::Int(i) => (true, i.bit_width().unwrap_or(ptr_bits) / 8, bx.cx.type_int_from_ty(i)),
+            ty::Uint(i) => {
+                (false, i.bit_width().unwrap_or(ptr_bits) / 8, bx.cx.type_uint_from_ty(i))
+            }
+            _ => {
+                return_error!(InvalidMonomorphization::ExpectedVectorElementType {
                     span,
                     name,
-                    elem_ty: arg_tys[0].simd_size_and_type(bx.tcx()).1,
-                    vec_ty: arg_tys[0],
+                    expected_element: arg_tys[0].simd_size_and_type(bx.tcx()).1,
+                    vector_type: arg_tys[0],
                 });
             }
         };
 
-        let result =
-            match (signed, is_add) {
-                (false, true) => {
-                    let res = lhs + rhs;
-                    let cmp = bx.context.new_comparison(None, ComparisonOp::LessThan, res, lhs);
-                    res | cmp
-                },
-                (true, true) => {
-                    // Algorithm from: https://codereview.stackexchange.com/questions/115869/saturated-signed-addition
-                    // TODO(antoyo): improve using conditional operators if possible.
-                    // TODO(antoyo): dyncast_vector should not require a call to unqualified.
-                    let arg_type = lhs.get_type().unqualified();
-                    // TODO(antoyo): convert lhs and rhs to unsigned.
-                    let sum = lhs + rhs;
-                    let vector_type = arg_type.dyncast_vector().expect("vector type");
-                    let unit = vector_type.get_num_units();
-                    let a = bx.context.new_rvalue_from_int(elem_ty, ((elem_width as i32) << 3) - 1);
-                    let width = bx.context.new_rvalue_from_vector(None, lhs.get_type(), &vec![a; unit]);
-
-                    let xor1 = lhs ^ rhs;
-                    let xor2 = lhs ^ sum;
-                    let and = bx.context.new_unary_op(None, UnaryOp::BitwiseNegate, arg_type, xor1) & xor2;
-                    let mask = and >> width;
-
-                    let one = bx.context.new_rvalue_one(elem_ty);
-                    let ones = bx.context.new_rvalue_from_vector(None, lhs.get_type(), &vec![one; unit]);
-                    let shift1 = ones << width;
-                    let shift2 = sum >> width;
-                    let mask_min = shift1 ^ shift2;
-
-                    let and1 = bx.context.new_unary_op(None, UnaryOp::BitwiseNegate, arg_type, mask) & sum;
-                    let and2 = mask & mask_min;
-
-                    and1 + and2
-                },
-                (false, false) => {
-                    let res = lhs - rhs;
-                    let cmp = bx.context.new_comparison(None, ComparisonOp::LessThanEquals, res, lhs);
-                    res & cmp
-                },
-                (true, false) => {
-                    // TODO(antoyo): dyncast_vector should not require a call to unqualified.
-                    let arg_type = lhs.get_type().unqualified();
-                    // TODO(antoyo): this uses the same algorithm from saturating add, but add the
-                    // negative of the right operand. Find a proper subtraction algorithm.
-                    let rhs = bx.context.new_unary_op(None, UnaryOp::Minus, arg_type, rhs);
-
-                    // TODO(antoyo): convert lhs and rhs to unsigned.
-                    let sum = lhs + rhs;
-                    let vector_type = arg_type.dyncast_vector().expect("vector type");
-                    let unit = vector_type.get_num_units();
-                    let a = bx.context.new_rvalue_from_int(elem_ty, ((elem_width as i32) << 3) - 1);
-                    let width = bx.context.new_rvalue_from_vector(None, lhs.get_type(), &vec![a; unit]);
-
-                    let xor1 = lhs ^ rhs;
-                    let xor2 = lhs ^ sum;
-                    let and = bx.context.new_unary_op(None, UnaryOp::BitwiseNegate, arg_type, xor1) & xor2;
-                    let mask = and >> width;
-
-                    let one = bx.context.new_rvalue_one(elem_ty);
-                    let ones = bx.context.new_rvalue_from_vector(None, lhs.get_type(), &vec![one; unit]);
-                    let shift1 = ones << width;
-                    let shift2 = sum >> width;
-                    let mask_min = shift1 ^ shift2;
-
-                    let and1 = bx.context.new_unary_op(None, UnaryOp::BitwiseNegate, arg_type, mask) & sum;
-                    let and2 = mask & mask_min;
-
-                    and1 + and2
-                }
-            };
+        let result = match (signed, is_add) {
+            (false, true) => {
+                let res = lhs + rhs;
+                let cmp = bx.context.new_comparison(None, ComparisonOp::LessThan, res, lhs);
+                res | cmp
+            }
+            (true, true) => {
+                // Algorithm from: https://codereview.stackexchange.com/questions/115869/saturated-signed-addition
+                // TODO(antoyo): improve using conditional operators if possible.
+                // TODO(antoyo): dyncast_vector should not require a call to unqualified.
+                let arg_type = lhs.get_type().unqualified();
+                // TODO(antoyo): convert lhs and rhs to unsigned.
+                let sum = lhs + rhs;
+                let vector_type = arg_type.dyncast_vector().expect("vector type");
+                let unit = vector_type.get_num_units();
+                let a = bx.context.new_rvalue_from_int(elem_ty, ((elem_width as i32) << 3) - 1);
+                let width = bx.context.new_rvalue_from_vector(None, lhs.get_type(), &vec![a; unit]);
+
+                let xor1 = lhs ^ rhs;
+                let xor2 = lhs ^ sum;
+                let and =
+                    bx.context.new_unary_op(None, UnaryOp::BitwiseNegate, arg_type, xor1) & xor2;
+                let mask = and >> width;
+
+                let one = bx.context.new_rvalue_one(elem_ty);
+                let ones =
+                    bx.context.new_rvalue_from_vector(None, lhs.get_type(), &vec![one; unit]);
+                let shift1 = ones << width;
+                let shift2 = sum >> width;
+                let mask_min = shift1 ^ shift2;
+
+                let and1 =
+                    bx.context.new_unary_op(None, UnaryOp::BitwiseNegate, arg_type, mask) & sum;
+                let and2 = mask & mask_min;
+
+                and1 + and2
+            }
+            (false, false) => {
+                let res = lhs - rhs;
+                let cmp = bx.context.new_comparison(None, ComparisonOp::LessThanEquals, res, lhs);
+                res & cmp
+            }
+            (true, false) => {
+                // TODO(antoyo): dyncast_vector should not require a call to unqualified.
+                let arg_type = lhs.get_type().unqualified();
+                // TODO(antoyo): this uses the same algorithm from saturating add, but add the
+                // negative of the right operand. Find a proper subtraction algorithm.
+                let rhs = bx.context.new_unary_op(None, UnaryOp::Minus, arg_type, rhs);
+
+                // TODO(antoyo): convert lhs and rhs to unsigned.
+                let sum = lhs + rhs;
+                let vector_type = arg_type.dyncast_vector().expect("vector type");
+                let unit = vector_type.get_num_units();
+                let a = bx.context.new_rvalue_from_int(elem_ty, ((elem_width as i32) << 3) - 1);
+                let width = bx.context.new_rvalue_from_vector(None, lhs.get_type(), &vec![a; unit]);
+
+                let xor1 = lhs ^ rhs;
+                let xor2 = lhs ^ sum;
+                let and =
+                    bx.context.new_unary_op(None, UnaryOp::BitwiseNegate, arg_type, xor1) & xor2;
+                let mask = and >> width;
+
+                let one = bx.context.new_rvalue_one(elem_ty);
+                let ones =
+                    bx.context.new_rvalue_from_vector(None, lhs.get_type(), &vec![one; unit]);
+                let shift1 = ones << width;
+                let shift2 = sum >> width;
+                let mask_min = shift1 ^ shift2;
+
+                let and1 =
+                    bx.context.new_unary_op(None, UnaryOp::BitwiseNegate, arg_type, mask) & sum;
+                let and2 = mask & mask_min;
+
+                and1 + and2
+            }
+        };
 
         return Ok(result);
     }
@@ -925,7 +952,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
             if name == sym::$name {
                 require!(
                     ret_ty == in_elem,
-                    InvalidMonomorphizationReturnType { span, name, in_elem, in_ty, ret_ty }
+                    InvalidMonomorphization::ReturnType { span, name, in_elem, in_ty, ret_ty }
                 );
                 return match in_elem.kind() {
                     ty::Int(_) | ty::Uint(_) => {
@@ -947,11 +974,12 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                             Ok(bx.vector_reduce_op(args[0].immediate(), $vec_op))
                         }
                     }
-                    _ => return_error!(InvalidMonomorphizationUnsupportedElement {
+                    _ => return_error!(InvalidMonomorphization::UnsupportedSymbol {
                         span,
                         name,
+                        symbol: sym::$name,
                         in_ty,
-                        elem_ty: in_elem,
+                        in_elem,
                         ret_ty
                     }),
                 };
@@ -988,18 +1016,24 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         1.0
     );
 
-
     macro_rules! minmax_red {
         ($name:ident: $int_red:ident, $float_red:ident) => {
             if name == sym::$name {
                 require!(
                     ret_ty == in_elem,
-                    InvalidMonomorphizationReturnType { span, name, in_elem, in_ty, ret_ty }
+                    InvalidMonomorphization::ReturnType { span, name, in_elem, in_ty, ret_ty }
                 );
                 return match in_elem.kind() {
                     ty::Int(_) | ty::Uint(_) => Ok(bx.$int_red(args[0].immediate())),
                     ty::Float(_) => Ok(bx.$float_red(args[0].immediate())),
-                    _ => return_error!(InvalidMonomorphizationUnsupportedElement { span, name, in_ty, elem_ty: in_elem, ret_ty }),
+                    _ => return_error!(InvalidMonomorphization::UnsupportedSymbol {
+                        span,
+                        name,
+                        symbol: sym::$name,
+                        in_ty,
+                        in_elem,
+                        ret_ty
+                    }),
                 };
             }
         };
@@ -1017,17 +1051,18 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                 let input = if !$boolean {
                     require!(
                         ret_ty == in_elem,
-                        InvalidMonomorphizationReturnType { span, name, in_elem, in_ty, ret_ty }
+                        InvalidMonomorphization::ReturnType { span, name, in_elem, in_ty, ret_ty }
                     );
                     args[0].immediate()
                 } else {
                     match in_elem.kind() {
                         ty::Int(_) | ty::Uint(_) => {}
-                        _ => return_error!(InvalidMonomorphizationUnsupportedElement {
+                        _ => return_error!(InvalidMonomorphization::UnsupportedSymbol {
                             span,
                             name,
+                            symbol: sym::$name,
                             in_ty,
-                            elem_ty: in_elem,
+                            in_elem,
                             ret_ty
                         }),
                     }
@@ -1037,13 +1072,22 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                 return match in_elem.kind() {
                     ty::Int(_) | ty::Uint(_) => {
                         let r = bx.vector_reduce_op(input, $op);
-                        Ok(if !$boolean { r } else { bx.icmp(IntPredicate::IntNE, r, bx.context.new_rvalue_zero(r.get_type())) })
+                        Ok(if !$boolean {
+                            r
+                        } else {
+                            bx.icmp(
+                                IntPredicate::IntNE,
+                                r,
+                                bx.context.new_rvalue_zero(r.get_type()),
+                            )
+                        })
                     }
-                    _ => return_error!(InvalidMonomorphizationUnsupportedElement {
+                    _ => return_error!(InvalidMonomorphization::UnsupportedSymbol {
                         span,
                         name,
+                        symbol: sym::$name,
                         in_ty,
-                        elem_ty: in_elem,
+                        in_elem,
                         ret_ty
                     }),
                 };
diff --git a/src/lib.rs b/src/lib.rs
index 4e9c2f91be5..7b55a4e4082 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -64,13 +64,19 @@ mod type_of;
 
 use std::any::Any;
 use std::sync::Arc;
+#[cfg(not(feature="master"))]
+use std::sync::atomic::{AtomicBool, Ordering};
 
 use crate::errors::LTONotSupported;
-use gccjit::{Context, OptimizationLevel, TargetInfo};
+use gccjit::{Context, OptimizationLevel};
+#[cfg(feature="master")]
+use gccjit::TargetInfo;
+#[cfg(not(feature="master"))]
+use gccjit::CType;
 use rustc_ast::expand::allocator::AllocatorKind;
 use rustc_codegen_ssa::{CodegenResults, CompiledModule, ModuleCodegen};
 use rustc_codegen_ssa::base::codegen_crate;
-use rustc_codegen_ssa::back::write::{CodegenContext, FatLTOInput, ModuleConfig, TargetMachineFactoryFn};
+use rustc_codegen_ssa::back::write::{CodegenContext, FatLtoInput, ModuleConfig, TargetMachineFactoryFn};
 use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
 use rustc_codegen_ssa::target_features::supported_target_features;
 use rustc_codegen_ssa::traits::{CodegenBackend, ExtraBackendMethods, ModuleBufferMethods, ThinBufferMethods, WriteBackendMethods};
@@ -85,6 +91,8 @@ use rustc_session::config::{Lto, OptLevel, OutputFilenames};
 use rustc_session::Session;
 use rustc_span::Symbol;
 use rustc_span::fatal_error::FatalError;
+#[cfg(not(feature="master"))]
+use tempfile::TempDir;
 
 fluent_messages! { "../messages.ftl" }
 
@@ -98,6 +106,23 @@ impl<F: Fn() -> String> Drop for PrintOnPanic<F> {
     }
 }
 
+#[cfg(not(feature="master"))]
+#[derive(Debug)]
+pub struct TargetInfo {
+    supports_128bit_integers: AtomicBool,
+}
+
+#[cfg(not(feature="master"))]
+impl TargetInfo {
+    fn cpu_supports(&self, _feature: &str) -> bool {
+        false
+    }
+
+    fn supports_128bit_int(&self) -> bool {
+        self.supports_128bit_integers.load(Ordering::SeqCst)
+    }
+}
+
 #[derive(Clone)]
 pub struct GccCodegenBackend {
     target_info: Arc<TargetInfo>,
@@ -114,6 +139,18 @@ impl CodegenBackend for GccCodegenBackend {
         if sess.lto() != Lto::No {
             sess.emit_warning(LTONotSupported {});
         }
+
+        #[cfg(not(feature="master"))]
+        {
+            let temp_dir = TempDir::new().expect("cannot create temporary directory");
+            let temp_file = temp_dir.into_path().join("result.asm");
+            let check_context = Context::default();
+            check_context.set_print_errors_to_stderr(false);
+            let _int128_ty = check_context.new_c_type(CType::UInt128t);
+            // NOTE: we cannot just call compile() as this would require other files than libgccjit.so.
+            check_context.compile_to_file(gccjit::OutputKind::Assembler, temp_file.to_str().expect("path to str"));
+            self.target_info.supports_128bit_integers.store(check_context.get_last_error() == Ok(None), Ordering::SeqCst);
+        }
     }
 
     fn provide(&self, providers: &mut Providers) {
@@ -206,14 +243,14 @@ impl WriteBackendMethods for GccCodegenBackend {
     type ThinData = ();
     type ThinBuffer = ThinBuffer;
 
-    fn run_fat_lto(_cgcx: &CodegenContext<Self>, mut modules: Vec<FatLTOInput<Self>>, _cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>) -> Result<LtoModuleCodegen<Self>, FatalError> {
+    fn run_fat_lto(_cgcx: &CodegenContext<Self>, mut modules: Vec<FatLtoInput<Self>>, _cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>) -> Result<LtoModuleCodegen<Self>, FatalError> {
         // TODO(antoyo): implement LTO by sending -flto to libgccjit and adding the appropriate gcc linker plugins.
         // NOTE: implemented elsewhere.
         // TODO(antoyo): what is implemented elsewhere ^ ?
         let module =
             match modules.remove(0) {
-                FatLTOInput::InMemory(module) => module,
-                FatLTOInput::Serialized { .. } => {
+                FatLtoInput::InMemory(module) => module,
+                FatLtoInput::Serialized { .. } => {
                     unimplemented!();
                 }
             };
@@ -228,6 +265,10 @@ impl WriteBackendMethods for GccCodegenBackend {
         unimplemented!();
     }
 
+    fn print_statistics(&self) {
+        unimplemented!()
+    }
+
     unsafe fn optimize(_cgcx: &CodegenContext<Self>, _diag_handler: &Handler, module: &ModuleCodegen<Self::Module>, config: &ModuleConfig) -> Result<(), FatalError> {
         module.module_llvm.context.set_optimization_level(to_gcc_opt_level(config.opt_level));
         Ok(())
@@ -262,14 +303,21 @@ impl WriteBackendMethods for GccCodegenBackend {
 /// This is the entrypoint for a hot plugged rustc_codegen_gccjit
 #[no_mangle]
 pub fn __rustc_codegen_backend() -> Box<dyn CodegenBackend> {
-    // Get the native arch and check whether the target supports 128-bit integers.
-    let context = Context::default();
-    let arch = context.get_target_info().arch().unwrap();
-
-    // Get the second TargetInfo with the correct CPU features by setting the arch.
-    let context = Context::default();
-    context.add_driver_option(&format!("-march={}", arch.to_str().unwrap()));
-    let target_info = Arc::new(context.get_target_info());
+    #[cfg(feature="master")]
+    let target_info = {
+        // Get the native arch and check whether the target supports 128-bit integers.
+        let context = Context::default();
+        let arch = context.get_target_info().arch().unwrap();
+
+        // Get the second TargetInfo with the correct CPU features by setting the arch.
+        let context = Context::default();
+        context.add_driver_option(&format!("-march={}", arch.to_str().unwrap()));
+        Arc::new(context.get_target_info())
+    };
+    #[cfg(not(feature="master"))]
+    let target_info = Arc::new(TargetInfo {
+        supports_128bit_integers: AtomicBool::new(false),
+    });
 
     Box::new(GccCodegenBackend {
         target_info,
@@ -315,14 +363,7 @@ pub fn target_features(sess: &Session, allow_unstable: bool, target_info: &Arc<T
             },
         )
         .filter(|_feature| {
-            #[cfg(feature="master")]
-            {
-                target_info.cpu_supports(_feature)
-            }
-            #[cfg(not(feature="master"))]
-            {
-                false
-            }
+            target_info.cpu_supports(_feature)
             /*
                adx, aes, avx, avx2, avx512bf16, avx512bitalg, avx512bw, avx512cd, avx512dq, avx512er, avx512f, avx512ifma,
                avx512pf, avx512vbmi, avx512vbmi2, avx512vl, avx512vnni, avx512vp2intersect, avx512vpopcntdq,
diff --git a/src/mono_item.rs b/src/mono_item.rs
index 342b830cedb..3322d56513b 100644
--- a/src/mono_item.rs
+++ b/src/mono_item.rs
@@ -31,7 +31,7 @@ impl<'gcc, 'tcx> PreDefineMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
 
     #[cfg_attr(not(feature="master"), allow(unused_variables))]
     fn predefine_fn(&self, instance: Instance<'tcx>, linkage: Linkage, visibility: Visibility, symbol_name: &str) {
-        assert!(!instance.substs.has_infer());
+        assert!(!instance.args.has_infer());
 
         let fn_abi = self.fn_abi_of_instance(instance, ty::List::empty());
         self.linkage.set(base::linkage_to_gcc(linkage));
diff --git a/src/type_.rs b/src/type_.rs
index 521b64ad34d..31899740514 100644
--- a/src/type_.rs
+++ b/src/type_.rs
@@ -54,6 +54,23 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
         self.u128_type
     }
 
+    pub fn type_ptr_to(&self, ty: Type<'gcc>) -> Type<'gcc> {
+        ty.make_pointer()
+    }
+
+    pub fn type_ptr_to_ext(&self, ty: Type<'gcc>, _address_space: AddressSpace) -> Type<'gcc> {
+        // TODO(antoyo): use address_space, perhaps with TYPE_ADDR_SPACE?
+        ty.make_pointer()
+    }
+
+    pub fn type_i8p(&self) -> Type<'gcc> {
+        self.type_ptr_to(self.type_i8())
+    }
+
+    pub fn type_i8p_ext(&self, address_space: AddressSpace) -> Type<'gcc> {
+        self.type_ptr_to_ext(self.type_i8(), address_space)
+    }
+
     pub fn type_pointee_for_align(&self, align: Align) -> Type<'gcc> {
         // FIXME(eddyb) We could find a better approximation if ity.align < align.
         let ity = Integer::approximate_align(self, align);
@@ -149,13 +166,12 @@ impl<'gcc, 'tcx> BaseTypeMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
         }
     }
 
-    fn type_ptr_to(&self, ty: Type<'gcc>) -> Type<'gcc> {
-        ty.make_pointer()
+    fn type_ptr(&self) -> Type<'gcc> {
+        self.type_ptr_to(self.type_void())
     }
 
-    fn type_ptr_to_ext(&self, ty: Type<'gcc>, _address_space: AddressSpace) -> Type<'gcc> {
-        // TODO(antoyo): use address_space, perhaps with TYPE_ADDR_SPACE?
-        ty.make_pointer()
+    fn type_ptr_ext(&self, address_space: AddressSpace) -> Type<'gcc> {
+        self.type_ptr_to_ext(self.type_void(), address_space)
     }
 
     fn element_type(&self, ty: Type<'gcc>) -> Type<'gcc> {
diff --git a/src/type_of.rs b/src/type_of.rs
index 74f016cf90a..84d57838512 100644
--- a/src/type_of.rs
+++ b/src/type_of.rs
@@ -101,7 +101,7 @@ fn uncached_gcc_type<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, layout: TyAndLayout
             if let (&ty::Generator(_, _, _), &Variants::Single { index }) =
                 (layout.ty.kind(), &layout.variants)
             {
-                write!(&mut name, "::{}", ty::GeneratorSubsts::variant_name(index)).unwrap();
+                write!(&mut name, "::{}", ty::GeneratorArgs::variant_name(index)).unwrap();
             }
             Some(name)
         }
@@ -282,8 +282,8 @@ impl<'tcx> LayoutGccExt<'tcx> for TyAndLayout<'tcx> {
             }
             // only wide pointer boxes are handled as pointers
             // thin pointer boxes with scalar allocators are handled by the general logic below
-            ty::Adt(def, substs) if def.is_box() && cx.layout_of(substs.type_at(1)).is_zst() => {
-                let ptr_ty = cx.tcx.mk_mut_ptr(self.ty.boxed_ty());
+            ty::Adt(def, args) if def.is_box() && cx.layout_of(args.type_at(1)).is_zst() => {
+                let ptr_ty = Ty::new_mut_ptr(cx.tcx,self.ty.boxed_ty());
                 return cx.layout_of(ptr_ty).scalar_pair_element_gcc_type(cx, index, immediate);
             }
             _ => {}
diff --git a/test.sh b/test.sh
index 592997b8ab9..1054fdf7ea1 100755
--- a/test.sh
+++ b/test.sh
@@ -346,7 +346,9 @@ function test_rustc() {
     git checkout -- tests/ui/issues/auxiliary/issue-3136-a.rs # contains //~ERROR, but shouldn't be removed
 
     rm -r tests/ui/{abi*,extern/,unsized-locals/,proc-macro/,threads-sendsync/,thinlto/,borrowck/,chalkify/bugs/,test*,*lto*.rs,consts/const-float-bits-reject-conv.rs,consts/issue-miri-1910.rs} || true
-    rm tests/ui/mir/mir_heavy_promoted.rs # this tests is oom-killed in the CI.
+    rm tests/ui/mir/mir_heavy_promoted.rs # this test is oom-killed in the CI.
+    # Tests generating errors.
+    rm tests/ui/consts/const-eval/nonnull_as_ref_ub.rs tests/ui/consts/issue-94675.rs
     for test in $(rg --files-with-matches "thread|lto" tests/ui); do
       rm $test
     done
@@ -354,6 +356,8 @@ function test_rustc() {
     git checkout tests/ui/type-alias-impl-trait/auxiliary/cross_crate_ice.rs
     git checkout tests/ui/type-alias-impl-trait/auxiliary/cross_crate_ice2.rs
     git checkout tests/ui/macros/rfc-2011-nicer-assert-messages/auxiliary/common.rs
+    git checkout tests/ui/imports/ambiguous-1.rs
+    git checkout tests/ui/imports/ambiguous-4-extern.rs
 
     RUSTC_ARGS="$TEST_FLAGS -Csymbol-mangling-version=v0 -Zcodegen-backend="$(pwd)"/../target/"$CHANNEL"/librustc_codegen_gcc."$dylib_ext" --sysroot "$(pwd)"/../build_sysroot/sysroot"
 
diff --git a/tests/run/abort1.rs b/tests/run/abort1.rs
index 25041d93e74..6cb3dd90203 100644
--- a/tests/run/abort1.rs
+++ b/tests/run/abort1.rs
@@ -4,6 +4,7 @@
 //   status: signal
 
 #![feature(auto_traits, lang_items, no_core, start, intrinsics)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/abort2.rs b/tests/run/abort2.rs
index e7443c8dbe5..b7a928166b8 100644
--- a/tests/run/abort2.rs
+++ b/tests/run/abort2.rs
@@ -4,6 +4,7 @@
 //   status: signal
 
 #![feature(auto_traits, lang_items, no_core, start, intrinsics)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/array.rs b/tests/run/array.rs
index 49b28d98f2f..d2d60b75e63 100644
--- a/tests/run/array.rs
+++ b/tests/run/array.rs
@@ -8,6 +8,7 @@
 //     10
 
 #![feature(arbitrary_self_types, auto_traits, lang_items, no_core, start, intrinsics)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/assign.rs b/tests/run/assign.rs
index 427c1a25033..241acea5e49 100644
--- a/tests/run/assign.rs
+++ b/tests/run/assign.rs
@@ -5,7 +5,7 @@
 //     7 8
 //     10
 
-#![allow(unused_attributes)]
+#![allow(internal_features, unused_attributes)]
 #![feature(auto_traits, lang_items, no_core, start, intrinsics, track_caller)]
 
 #![no_std]
diff --git a/tests/run/closure.rs b/tests/run/closure.rs
index 8daa681abf7..764c5b34426 100644
--- a/tests/run/closure.rs
+++ b/tests/run/closure.rs
@@ -10,6 +10,7 @@
 
 #![feature(arbitrary_self_types, auto_traits, lang_items, no_core, start, intrinsics,
     unboxed_closures)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/condition.rs b/tests/run/condition.rs
index b7a13081dea..ed17c19409e 100644
--- a/tests/run/condition.rs
+++ b/tests/run/condition.rs
@@ -6,6 +6,7 @@
 //     1
 
 #![feature(arbitrary_self_types, auto_traits, lang_items, no_core, start, intrinsics)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/empty_main.rs b/tests/run/empty_main.rs
index c02cfd2a85f..2d78ef12aa7 100644
--- a/tests/run/empty_main.rs
+++ b/tests/run/empty_main.rs
@@ -4,6 +4,7 @@
 //   status: 0
 
 #![feature(auto_traits, lang_items, no_core, start)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/exit.rs b/tests/run/exit.rs
index 956e53dd4aa..bf1cbeef302 100644
--- a/tests/run/exit.rs
+++ b/tests/run/exit.rs
@@ -4,6 +4,7 @@
 //   status: 2
 
 #![feature(auto_traits, lang_items, no_core, start, intrinsics)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/exit_code.rs b/tests/run/exit_code.rs
index eeab3520951..be7a233efda 100644
--- a/tests/run/exit_code.rs
+++ b/tests/run/exit_code.rs
@@ -4,6 +4,7 @@
 //   status: 1
 
 #![feature(auto_traits, lang_items, no_core, start)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/fun_ptr.rs b/tests/run/fun_ptr.rs
index 8a196f774c8..e0c30cada6b 100644
--- a/tests/run/fun_ptr.rs
+++ b/tests/run/fun_ptr.rs
@@ -5,6 +5,7 @@
 //   stdout: 1
 
 #![feature(arbitrary_self_types, auto_traits, lang_items, no_core, start, intrinsics)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/int_overflow.rs b/tests/run/int_overflow.rs
index c3fcb3c0a2a..badcc0f7699 100644
--- a/tests/run/int_overflow.rs
+++ b/tests/run/int_overflow.rs
@@ -4,7 +4,7 @@
 //   stdout: Success
 //   status: signal
 
-#![allow(unused_attributes)]
+#![allow(internal_features, unused_attributes)]
 #![feature(auto_traits, lang_items, no_core, start, intrinsics)]
 
 #![no_std]
diff --git a/tests/run/mut_ref.rs b/tests/run/mut_ref.rs
index 2a2ea8b8bf0..e843e298537 100644
--- a/tests/run/mut_ref.rs
+++ b/tests/run/mut_ref.rs
@@ -7,7 +7,7 @@
 //     6
 //     11
 
-#![allow(unused_attributes)]
+#![allow(internal_features, unused_attributes)]
 #![feature(auto_traits, lang_items, no_core, start, intrinsics, track_caller)]
 
 #![no_std]
diff --git a/tests/run/operations.rs b/tests/run/operations.rs
index 67b9f241dbb..cac6fdfca4a 100644
--- a/tests/run/operations.rs
+++ b/tests/run/operations.rs
@@ -5,7 +5,7 @@
 //     39
 //     10
 
-#![allow(unused_attributes)]
+#![allow(internal_features, unused_attributes)]
 #![feature(auto_traits, lang_items, no_core, start, intrinsics, arbitrary_self_types)]
 
 #![no_std]
diff --git a/tests/run/ptr_cast.rs b/tests/run/ptr_cast.rs
index da8a8295d56..41866179828 100644
--- a/tests/run/ptr_cast.rs
+++ b/tests/run/ptr_cast.rs
@@ -5,6 +5,7 @@
 //   stdout: 1
 
 #![feature(arbitrary_self_types, auto_traits, lang_items, no_core, start, intrinsics)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/return-tuple.rs b/tests/run/return-tuple.rs
index 6fa10dca06f..8d40deb8c85 100644
--- a/tests/run/return-tuple.rs
+++ b/tests/run/return-tuple.rs
@@ -7,6 +7,7 @@
 //     42
 
 #![feature(auto_traits, lang_items, no_core, start, intrinsics)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/slice.rs b/tests/run/slice.rs
index 96f1c4792e5..25ff72549d4 100644
--- a/tests/run/slice.rs
+++ b/tests/run/slice.rs
@@ -5,6 +5,7 @@
 //   stdout: 5
 
 #![feature(arbitrary_self_types, auto_traits, lang_items, no_core, start, intrinsics)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/static.rs b/tests/run/static.rs
index 19201f1df26..2457bb1f443 100644
--- a/tests/run/static.rs
+++ b/tests/run/static.rs
@@ -10,6 +10,7 @@
 //      1
 
 #![feature(auto_traits, lang_items, no_core, start, intrinsics)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/structs.rs b/tests/run/structs.rs
index 6c8884855ac..d6455667400 100644
--- a/tests/run/structs.rs
+++ b/tests/run/structs.rs
@@ -6,6 +6,7 @@
 //     2
 
 #![feature(auto_traits, lang_items, no_core, start, intrinsics)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tests/run/tuple.rs b/tests/run/tuple.rs
index 0b670bf2674..8a7d85ae867 100644
--- a/tests/run/tuple.rs
+++ b/tests/run/tuple.rs
@@ -5,6 +5,7 @@
 //   stdout: 3
 
 #![feature(auto_traits, lang_items, no_core, start, intrinsics)]
+#![allow(internal_features)]
 
 #![no_std]
 #![no_core]
diff --git a/tools/generate_intrinsics.py b/tools/generate_intrinsics.py
index 6188924b0d5..83abe145e64 100644
--- a/tools/generate_intrinsics.py
+++ b/tools/generate_intrinsics.py
@@ -3,7 +3,6 @@
 import re
 import sys
 import subprocess
-from os import walk
 
 
 def run_command(command, cwd=None):
@@ -180,7 +179,7 @@ def update_intrinsics(llvm_path, llvmint, llvmint2):
             intrinsics[arch].sort(key=lambda x: (x[0], x[2]))
             out.write('    // {}\n'.format(arch))
             for entry in intrinsics[arch]:
-                if entry[2] == True: # if it is a duplicate
+                if entry[2] is True: # if it is a duplicate
                     out.write('    // [DUPLICATE]: "{}" => "{}",\n'.format(entry[0], entry[1]))
                 elif "_round_mask" in entry[1]:
                     out.write('    // [INVALID CONVERSION]: "{}" => "{}",\n'.format(entry[0], entry[1]))