diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f436c236dc958..767ea29d6369b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -58,7 +58,7 @@ jobs:
           - name: mingw-check-tidy
             os: ubuntu-20.04-4core-16gb
             env: {}
-          - name: x86_64-gnu-llvm-16
+          - name: x86_64-gnu-llvm-17
             env:
               ENABLE_GCC_CODEGEN: "1"
             os: ubuntu-20.04-16core-64gb
@@ -323,10 +323,6 @@ jobs:
             env:
               RUST_BACKTRACE: 1
             os: ubuntu-20.04-8core-32gb
-          - name: x86_64-gnu-llvm-16
-            env:
-              RUST_BACKTRACE: 1
-            os: ubuntu-20.04-8core-32gb
           - name: x86_64-gnu-nopt
             os: ubuntu-20.04-4core-16gb
             env: {}
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
index d75ff4565e6f0..825f8dad8e480 100644
--- a/compiler/rustc_ast/src/visit.rs
+++ b/compiler/rustc_ast/src/visit.rs
@@ -755,7 +755,7 @@ pub fn walk_assoc_item<'a, V: Visitor<'a>>(
         }
         AssocItemKind::Delegation(box Delegation { id, qself, path, body }) => {
             if let Some(qself) = qself {
-                visitor.visit_ty(&qself.ty);
+                try_visit!(visitor.visit_ty(&qself.ty));
             }
             try_visit!(visitor.visit_path(path, *id));
             visit_opt!(visitor, visit_block, body);
@@ -994,7 +994,7 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) -> V
         ExprKind::InlineAsm(asm) => try_visit!(visitor.visit_inline_asm(asm)),
         ExprKind::FormatArgs(f) => try_visit!(visitor.visit_format_args(f)),
         ExprKind::OffsetOf(container, fields) => {
-            visitor.visit_ty(container);
+            try_visit!(visitor.visit_ty(container));
             walk_list!(visitor, visit_ident, fields.iter().copied());
         }
         ExprKind::Yield(optional_expression) => {
diff --git a/compiler/rustc_ast_lowering/src/format.rs b/compiler/rustc_ast_lowering/src/format.rs
index 3f84e6b100d11..d2c3b8b2d5652 100644
--- a/compiler/rustc_ast_lowering/src/format.rs
+++ b/compiler/rustc_ast_lowering/src/format.rs
@@ -604,8 +604,7 @@ fn may_contain_yield_point(e: &ast::Expr) -> bool {
             if let ast::ExprKind::Await(_, _) | ast::ExprKind::Yield(_) = e.kind {
                 ControlFlow::Break(())
             } else {
-                visit::walk_expr(self, e);
-                ControlFlow::Continue(())
+                visit::walk_expr(self, e)
             }
         }
 
diff --git a/compiler/rustc_codegen_cranelift/src/constant.rs b/compiler/rustc_codegen_cranelift/src/constant.rs
index 39fa277fedc55..fc9b0f6ef024f 100644
--- a/compiler/rustc_codegen_cranelift/src/constant.rs
+++ b/compiler/rustc_codegen_cranelift/src/constant.rs
@@ -74,7 +74,7 @@ pub(crate) fn eval_mir_constant<'tcx>(
     let cv = fx.monomorphize(constant.const_);
     // This cannot fail because we checked all required_consts in advance.
     let val = cv
-        .eval(fx.tcx, ty::ParamEnv::reveal_all(), Some(constant.span))
+        .eval(fx.tcx, ty::ParamEnv::reveal_all(), constant.span)
         .expect("erroneous constant missed by mono item collection");
     (val, cv.ty())
 }
diff --git a/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs b/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
index 8b86a116df1fd..c802d9bbefbed 100644
--- a/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
@@ -728,8 +728,10 @@ fn codegen_regular_intrinsic_call<'tcx>(
         | sym::variant_count => {
             intrinsic_args!(fx, args => (); intrinsic);
 
-            let const_val =
-                fx.tcx.const_eval_instance(ParamEnv::reveal_all(), instance, None).unwrap();
+            let const_val = fx
+                .tcx
+                .const_eval_instance(ParamEnv::reveal_all(), instance, source_info.span)
+                .unwrap();
             let val = crate::constant::codegen_const_value(fx, const_val, ret.layout().ty);
             ret.write_cvalue(fx, val);
         }
diff --git a/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs b/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs
index 79da970a58efe..4d55a95aa9db7 100644
--- a/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs
+++ b/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs
@@ -131,7 +131,7 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
 
             let idx = generic_args[2]
                 .expect_const()
-                .eval(fx.tcx, ty::ParamEnv::reveal_all(), Some(span))
+                .eval(fx.tcx, ty::ParamEnv::reveal_all(), span)
                 .unwrap()
                 .unwrap_branch();
 
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index f89c8c9f836bf..c3f17563b0a61 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -126,17 +126,6 @@ pub unsafe fn create_module<'ll>(
 
     let mut target_data_layout = sess.target.data_layout.to_string();
     let llvm_version = llvm_util::get_version();
-    if llvm_version < (17, 0, 0) {
-        if sess.target.arch.starts_with("powerpc") {
-            // LLVM 17 specifies function pointer alignment for ppc:
-            // https://reviews.llvm.org/D147016
-            target_data_layout = target_data_layout
-                .replace("-Fn32", "")
-                .replace("-Fi32", "")
-                .replace("-Fn64", "")
-                .replace("-Fi64", "");
-        }
-    }
     if llvm_version < (18, 0, 0) {
         if sess.target.arch == "x86" || sess.target.arch == "x86_64" {
             // LLVM 18 adjusts i128 to be 128-bit aligned on x86 variants.
diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs
index 467e02d55e332..71b69a94e99e7 100644
--- a/compiler/rustc_codegen_llvm/src/intrinsic.rs
+++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs
@@ -1129,7 +1129,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
     if name == sym::simd_shuffle_generic {
         let idx = fn_args[2]
             .expect_const()
-            .eval(tcx, ty::ParamEnv::reveal_all(), Some(span))
+            .eval(tcx, ty::ParamEnv::reveal_all(), span)
             .unwrap()
             .unwrap_branch();
         let n = idx.len() as u64;
diff --git a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
index 5bd7442822a21..fcd7fa9247b0e 100644
--- a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
+++ b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
@@ -19,6 +19,7 @@ use rustc_hir::{CoroutineDesugaring, CoroutineKind, CoroutineSource, Mutability}
 use rustc_middle::ty::layout::{IntegerExt, TyAndLayout};
 use rustc_middle::ty::{self, ExistentialProjection, ParamEnv, Ty, TyCtxt};
 use rustc_middle::ty::{GenericArgKind, GenericArgsRef};
+use rustc_span::DUMMY_SP;
 use rustc_target::abi::Integer;
 use smallvec::SmallVec;
 
@@ -704,7 +705,7 @@ fn push_const_param<'tcx>(tcx: TyCtxt<'tcx>, ct: ty::Const<'tcx>, output: &mut S
                 // avoiding collisions and will make the emitted type names shorter.
                 let hash_short = tcx.with_stable_hashing_context(|mut hcx| {
                     let mut hasher = StableHasher::new();
-                    let ct = ct.eval(tcx, ty::ParamEnv::reveal_all(), None).unwrap();
+                    let ct = ct.eval(tcx, ty::ParamEnv::reveal_all(), DUMMY_SP).unwrap();
                     hcx.while_hashing_spans(false, |hcx| ct.hash_stable(hcx, &mut hasher));
                     hasher.finish::<Hash64>()
                 });
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 9bb2a52826585..02e7bb05b7709 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -1688,7 +1688,6 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub fn try_llbb(&mut self, bb: mir::BasicBlock) -> Option<Bx::BasicBlock> {
         match self.cached_llbbs[bb] {
             CachedLlbb::None => {
-                // FIXME(eddyb) only name the block if `fewer_names` is `false`.
                 let llbb = Bx::append_block(self.cx, self.llfn, &format!("{bb:?}"));
                 self.cached_llbbs[bb] = CachedLlbb::Some(llbb);
                 Some(llbb)
diff --git a/compiler/rustc_codegen_ssa/src/mir/constant.rs b/compiler/rustc_codegen_ssa/src/mir/constant.rs
index ff899c50b3de6..c6260d3591618 100644
--- a/compiler/rustc_codegen_ssa/src/mir/constant.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/constant.rs
@@ -24,7 +24,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         // `MirUsedCollector` visited all required_consts before codegen began, so if we got here
         // there can be no more constants that fail to evaluate.
         self.monomorphize(constant.const_)
-            .eval(self.cx.tcx(), ty::ParamEnv::reveal_all(), Some(constant.span))
+            .eval(self.cx.tcx(), ty::ParamEnv::reveal_all(), constant.span)
             .expect("erroneous constant missed by mono item collection")
     }
 
@@ -56,11 +56,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             other => span_bug!(constant.span, "{other:#?}"),
         };
         let uv = self.monomorphize(uv);
-        self.cx.tcx().const_eval_resolve_for_typeck(
-            ty::ParamEnv::reveal_all(),
-            uv,
-            Some(constant.span),
-        )
+        self.cx.tcx().const_eval_resolve_for_typeck(ty::ParamEnv::reveal_all(), uv, constant.span)
     }
 
     /// process constant containing SIMD shuffle indices
diff --git a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
index 1d1826d984474..ba023f96107a4 100644
--- a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
@@ -130,7 +130,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             | sym::variant_count => {
                 let value = bx
                     .tcx()
-                    .const_eval_instance(ty::ParamEnv::reveal_all(), instance, None)
+                    .const_eval_instance(ty::ParamEnv::reveal_all(), instance, span)
                     .unwrap();
                 OperandRef::from_const(bx, value, ret_ty).immediate_or_packed_pair(bx)
             }
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index 09e9cc4b35d31..730e8977803cd 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -826,7 +826,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             for &const_ in &body.required_consts {
                 let c = self
                     .instantiate_from_current_frame_and_normalize_erasing_regions(const_.const_)?;
-                c.eval(*self.tcx, self.param_env, Some(const_.span)).map_err(|err| {
+                c.eval(*self.tcx, self.param_env, const_.span).map_err(|err| {
                     err.emit_note(*self.tcx);
                     err
                 })?;
@@ -1174,7 +1174,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     pub fn eval_mir_constant(
         &self,
         val: &mir::Const<'tcx>,
-        span: Option<Span>,
+        span: Span,
         layout: Option<TyAndLayout<'tcx>>,
     ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {
         M::eval_mir_constant(self, *val, span, layout, |ecx, val, span, layout| {
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics.rs b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
index b68bfb4211d1e..748c7dce5a3ab 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
@@ -153,9 +153,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     sym::type_name => Ty::new_static_str(self.tcx.tcx),
                     _ => bug!(),
                 };
-                let val = self.ctfe_query(|tcx| {
-                    tcx.const_eval_global_id(self.param_env, gid, Some(tcx.span))
-                })?;
+                let val =
+                    self.ctfe_query(|tcx| tcx.const_eval_global_id(self.param_env, gid, tcx.span))?;
                 let val = self.const_val_to_op(val, ty, Some(dest.layout))?;
                 self.copy_op(&val, dest)?;
             }
diff --git a/compiler/rustc_const_eval/src/interpret/machine.rs b/compiler/rustc_const_eval/src/interpret/machine.rs
index afc4a80c283f4..827d8fd9417ce 100644
--- a/compiler/rustc_const_eval/src/interpret/machine.rs
+++ b/compiler/rustc_const_eval/src/interpret/machine.rs
@@ -525,7 +525,7 @@ pub trait Machine<'mir, 'tcx: 'mir>: Sized {
     fn eval_mir_constant<F>(
         ecx: &InterpCx<'mir, 'tcx, Self>,
         val: mir::Const<'tcx>,
-        span: Option<Span>,
+        span: Span,
         layout: Option<TyAndLayout<'tcx>>,
         eval: F,
     ) -> InterpResult<'tcx, OpTy<'tcx, Self::Provenance>>
@@ -533,7 +533,7 @@ pub trait Machine<'mir, 'tcx: 'mir>: Sized {
         F: Fn(
             &InterpCx<'mir, 'tcx, Self>,
             mir::Const<'tcx>,
-            Option<Span>,
+            Span,
             Option<TyAndLayout<'tcx>>,
         ) -> InterpResult<'tcx, OpTy<'tcx, Self::Provenance>>,
     {
diff --git a/compiler/rustc_const_eval/src/interpret/operand.rs b/compiler/rustc_const_eval/src/interpret/operand.rs
index e49067a2f0063..dbc6a317640c1 100644
--- a/compiler/rustc_const_eval/src/interpret/operand.rs
+++ b/compiler/rustc_const_eval/src/interpret/operand.rs
@@ -741,7 +741,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 // * During ConstProp, with `TooGeneric` or since the `required_consts` were not all
                 //   checked yet.
                 // * During CTFE, since promoteds in `const`/`static` initializer bodies can fail.
-                self.eval_mir_constant(&c, Some(constant.span), layout)?
+                self.eval_mir_constant(&c, constant.span, layout)?
             }
         };
         trace!("{:?}: {:?}", mir_op, op);
diff --git a/compiler/rustc_const_eval/src/transform/validate.rs b/compiler/rustc_const_eval/src/transform/validate.rs
index f26c8f8592dea..68270dab28443 100644
--- a/compiler/rustc_const_eval/src/transform/validate.rs
+++ b/compiler/rustc_const_eval/src/transform/validate.rs
@@ -341,7 +341,7 @@ impl<'a, 'tcx> Visitor<'tcx> for CfgChecker<'a, 'tcx> {
                 // FIXME(JakobDegen) The validator should check that `self.mir_phase <
                 // DropsLowered`. However, this causes ICEs with generation of drop shims, which
                 // seem to fail to set their `MirPhase` correctly.
-                if matches!(kind, RetagKind::Raw | RetagKind::TwoPhase) {
+                if matches!(kind, RetagKind::TwoPhase) {
                     self.fail(location, format!("explicit `{kind:?}` is forbidden"));
                 }
             }
@@ -1272,7 +1272,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                 // FIXME(JakobDegen) The validator should check that `self.mir_phase <
                 // DropsLowered`. However, this causes ICEs with generation of drop shims, which
                 // seem to fail to set their `MirPhase` correctly.
-                if matches!(kind, RetagKind::Raw | RetagKind::TwoPhase) {
+                if matches!(kind, RetagKind::TwoPhase) {
                     self.fail(location, format!("explicit `{kind:?}` is forbidden"));
                 }
             }
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
index fbbad38d17f10..186bb234a450b 100644
--- a/compiler/rustc_hir/src/intravisit.rs
+++ b/compiler/rustc_hir/src/intravisit.rs
@@ -899,7 +899,7 @@ pub fn walk_generic_param<'v, V: Visitor<'v>>(
         GenericParamKind::Const { ref ty, ref default, is_host_effect: _ } => {
             try_visit!(visitor.visit_ty(ty));
             if let Some(ref default) = default {
-                visitor.visit_const_param_default(param.hir_id, default);
+                try_visit!(visitor.visit_const_param_default(param.hir_id, default));
             }
         }
     }
diff --git a/compiler/rustc_hir_analysis/src/check/intrinsic.rs b/compiler/rustc_hir_analysis/src/check/intrinsic.rs
index bf5838143d945..35755a46df3a4 100644
--- a/compiler/rustc_hir_analysis/src/check/intrinsic.rs
+++ b/compiler/rustc_hir_analysis/src/check/intrinsic.rs
@@ -658,10 +658,6 @@ pub fn check_intrinsic_type(
             sym::simd_shuffle => (3, 0, vec![param(0), param(0), param(1)], param(2)),
             sym::simd_shuffle_generic => (2, 1, vec![param(0), param(0)], param(1)),
 
-            sym::retag_box_to_raw => {
-                (2, 0, vec![Ty::new_mut_ptr(tcx, param(0))], Ty::new_mut_ptr(tcx, param(0)))
-            }
-
             other => {
                 tcx.dcx().emit_err(UnrecognizedIntrinsicFunction { span, name: other });
                 return;
diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs
index 553729503688c..491da7eb2c2a9 100644
--- a/compiler/rustc_hir_typeck/src/pat.rs
+++ b/compiler/rustc_hir_typeck/src/pat.rs
@@ -2178,7 +2178,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         len: ty::Const<'tcx>,
         min_len: u64,
     ) -> (Option<Ty<'tcx>>, Ty<'tcx>) {
-        let len = match len.eval(self.tcx, self.param_env, None) {
+        let len = match len.eval(self.tcx, self.param_env, span) {
             Ok(val) => val
                 .try_to_scalar()
                 .and_then(|scalar| scalar.try_to_int().ok())
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index 89e4e88b3df24..44e14387c5c8b 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -1475,7 +1475,7 @@ impl<'tcx> InferCtxt<'tcx> {
         param_env: ty::ParamEnv<'tcx>,
         unevaluated: ty::UnevaluatedConst<'tcx>,
         ty: Ty<'tcx>,
-        span: Option<Span>,
+        span: Span,
     ) -> Result<ty::Const<'tcx>, ErrorHandled> {
         match self.const_eval_resolve(param_env, unevaluated, span) {
             Ok(Some(val)) => Ok(ty::Const::new_value(self.tcx, val, ty)),
@@ -1509,7 +1509,7 @@ impl<'tcx> InferCtxt<'tcx> {
         &self,
         mut param_env: ty::ParamEnv<'tcx>,
         unevaluated: ty::UnevaluatedConst<'tcx>,
-        span: Option<Span>,
+        span: Span,
     ) -> EvalToValTreeResult<'tcx> {
         let mut args = self.resolve_vars_if_possible(unevaluated.args);
         debug!(?args);
@@ -1521,12 +1521,9 @@ impl<'tcx> InferCtxt<'tcx> {
             if let Some(ct) = tcx.thir_abstract_const(unevaluated.def)? {
                 let ct = tcx.expand_abstract_consts(ct.instantiate(tcx, args));
                 if let Err(e) = ct.error_reported() {
-                    return Err(ErrorHandled::Reported(
-                        e.into(),
-                        span.unwrap_or(rustc_span::DUMMY_SP),
-                    ));
+                    return Err(ErrorHandled::Reported(e.into(), span));
                 } else if ct.has_non_region_infer() || ct.has_non_region_param() {
-                    return Err(ErrorHandled::TooGeneric(span.unwrap_or(rustc_span::DUMMY_SP)));
+                    return Err(ErrorHandled::TooGeneric(span));
                 } else {
                     args = replace_param_and_infer_args_with_placeholder(tcx, args);
                 }
diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
index f6253068eaa63..067374c026107 100644
--- a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
@@ -24,9 +24,7 @@
 #include "llvm/Passes/StandardInstrumentations.h"
 #include "llvm/Support/CBindingWrapping.h"
 #include "llvm/Support/FileSystem.h"
-#if LLVM_VERSION_GE(17, 0)
 #include "llvm/Support/VirtualFileSystem.h"
-#endif
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Transforms/IPO/AlwaysInliner.h"
 #include "llvm/Transforms/IPO/FunctionImport.h"
@@ -334,14 +332,8 @@ extern "C" void LLVMRustPrintTargetCPUs(LLVMTargetMachineRef TM,
 
   std::ostringstream Buf;
 
-#if LLVM_VERSION_GE(17, 0)
   const MCSubtargetInfo *MCInfo = Target->getMCSubtargetInfo();
   const ArrayRef<SubtargetSubTypeKV> CPUTable = MCInfo->getAllProcessorDescriptions();
-#else
-  Buf << "Full target CPU help is not supported by this LLVM version.\n\n";
-  SubtargetSubTypeKV TargetCPUKV = { TargetCPU, {{}}, {{}} };
-  const ArrayRef<SubtargetSubTypeKV> CPUTable = TargetCPUKV;
-#endif
   unsigned MaxCPULen = getLongestEntryLength(CPUTable);
 
   Buf << "Available CPUs for this target:\n";
@@ -476,10 +468,6 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
   Options.RelaxELFRelocations = RelaxELFRelocations;
 #endif
   Options.UseInitArray = UseInitArray;
-
-#if LLVM_VERSION_LT(17, 0)
-  Options.ExplicitEmulatedTLS = true;
-#endif
   Options.EmulatedTLS = UseEmulatedTls;
 
   if (TrapUnreachable) {
@@ -761,16 +749,10 @@ LLVMRustOptimize(
   }
 
   std::optional<PGOOptions> PGOOpt;
-#if LLVM_VERSION_GE(17, 0)
   auto FS = vfs::getRealFileSystem();
-#endif
   if (PGOGenPath) {
     assert(!PGOUsePath && !PGOSampleUsePath);
-    PGOOpt = PGOOptions(PGOGenPath, "", "",
-#if LLVM_VERSION_GE(17, 0)
-                        "",
-                        FS,
-#endif
+    PGOOpt = PGOOptions(PGOGenPath, "", "", "", FS,
                         PGOOptions::IRInstr, PGOOptions::NoCSAction,
 #if LLVM_VERSION_GE(19, 0)
                         PGOOptions::ColdFuncOpt::Default,
@@ -778,33 +760,21 @@ LLVMRustOptimize(
                         DebugInfoForProfiling);
   } else if (PGOUsePath) {
     assert(!PGOSampleUsePath);
-    PGOOpt = PGOOptions(PGOUsePath, "", "",
-#if LLVM_VERSION_GE(17, 0)
-                        "",
-                        FS,
-#endif
+    PGOOpt = PGOOptions(PGOUsePath, "", "", "", FS,
                         PGOOptions::IRUse, PGOOptions::NoCSAction,
 #if LLVM_VERSION_GE(19, 0)
                         PGOOptions::ColdFuncOpt::Default,
 #endif
                         DebugInfoForProfiling);
   } else if (PGOSampleUsePath) {
-    PGOOpt = PGOOptions(PGOSampleUsePath, "", "",
-#if LLVM_VERSION_GE(17, 0)
-                        "",
-                        FS,
-#endif
+    PGOOpt = PGOOptions(PGOSampleUsePath, "", "", "", FS,
                         PGOOptions::SampleUse, PGOOptions::NoCSAction,
 #if LLVM_VERSION_GE(19, 0)
                         PGOOptions::ColdFuncOpt::Default,
 #endif
                         DebugInfoForProfiling);
   } else if (DebugInfoForProfiling) {
-    PGOOpt = PGOOptions("", "", "",
-#if LLVM_VERSION_GE(17, 0)
-                        "",
-                        FS,
-#endif
+    PGOOpt = PGOOptions("", "", "", "", FS,
                         PGOOptions::NoAction, PGOOptions::NoCSAction,
 #if LLVM_VERSION_GE(19, 0)
                         PGOOptions::ColdFuncOpt::Default,
@@ -1353,9 +1323,7 @@ LLVMRustCreateThinLTOData(LLVMRustThinLTOModule *modules,
   ComputeCrossModuleImport(
     Ret->Index,
     Ret->ModuleToDefinedGVSummaries,
-#if LLVM_VERSION_GE(17, 0)
     isPrevailing,
-#endif
     Ret->ImportLists,
     Ret->ExportLists
   );
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index 91f54da5c12f7..f6ec410bfac21 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -2152,19 +2152,3 @@ extern "C" LLVMValueRef LLVMConstStringInContext2(LLVMContextRef C,
   return wrap(ConstantDataArray::getString(*unwrap(C), StringRef(Str, Length), !DontNullTerminate));
 }
 #endif
-
-// FIXME: Remove when Rust's minimum supported LLVM version reaches 17.
-// https://github.com/llvm/llvm-project/commit/35276f16e5a2cae0dfb49c0fbf874d4d2f177acc
-#if LLVM_VERSION_LT(17, 0)
-extern "C" LLVMValueRef LLVMConstArray2(LLVMTypeRef ElementTy,
-                                        LLVMValueRef *ConstantVals,
-                                        uint64_t Length) {
-  ArrayRef<Constant *> V(unwrap<Constant>(ConstantVals, Length), Length);
-  return wrap(ConstantArray::get(ArrayType::get(unwrap(ElementTy), Length), V));
-}
-
-extern "C" LLVMTypeRef LLVMArrayType2(LLVMTypeRef ElementTy,
-                                      uint64_t ElementCount) {
-  return wrap(ArrayType::get(unwrap(ElementTy), ElementCount));
-}
-#endif
diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index 0467cf2969fc5..03783fa97987a 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -1590,17 +1590,17 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             })
         }
 
-        // Translate the virtual `/rustc/$hash` prefix back to a real directory
-        // that should hold actual sources, where possible.
-        //
-        // NOTE: if you update this, you might need to also update bootstrap's code for generating
-        // the `rust-src` component in `Src::run` in `src/bootstrap/dist.rs`.
-        let virtual_rust_source_base_dir = [
-            filter(sess, option_env!("CFG_VIRTUAL_RUST_SOURCE_BASE_DIR").map(Path::new)),
-            filter(sess, sess.opts.unstable_opts.simulate_remapped_rust_src_base.as_deref()),
-        ];
-
         let try_to_translate_virtual_to_real = |name: &mut rustc_span::FileName| {
+            // Translate the virtual `/rustc/$hash` prefix back to a real directory
+            // that should hold actual sources, where possible.
+            //
+            // NOTE: if you update this, you might need to also update bootstrap's code for generating
+            // the `rust-src` component in `Src::run` in `src/bootstrap/dist.rs`.
+            let virtual_rust_source_base_dir = [
+                filter(sess, option_env!("CFG_VIRTUAL_RUST_SOURCE_BASE_DIR").map(Path::new)),
+                filter(sess, sess.opts.unstable_opts.simulate_remapped_rust_src_base.as_deref()),
+            ];
+
             debug!(
                 "try_to_translate_virtual_to_real(name={:?}): \
                  virtual_rust_source_base_dir={:?}, real_rust_source_base_dir={:?}",
diff --git a/compiler/rustc_middle/src/mir/consts.rs b/compiler/rustc_middle/src/mir/consts.rs
index 5feee3c3ba10f..214297b98695f 100644
--- a/compiler/rustc_middle/src/mir/consts.rs
+++ b/compiler/rustc_middle/src/mir/consts.rs
@@ -2,7 +2,7 @@ use std::fmt::{self, Debug, Display, Formatter};
 
 use rustc_hir::def_id::DefId;
 use rustc_session::RemapFileNameExt;
-use rustc_span::Span;
+use rustc_span::{Span, DUMMY_SP};
 use rustc_target::abi::{HasDataLayout, Size};
 
 use crate::mir::interpret::{alloc_range, AllocId, ConstAllocation, ErrorHandled, Scalar};
@@ -273,7 +273,7 @@ impl<'tcx> Const<'tcx> {
         self,
         tcx: TyCtxt<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
-        span: Option<Span>,
+        span: Span,
     ) -> Result<ConstValue<'tcx>, ErrorHandled> {
         match self {
             Const::Ty(c) => {
@@ -293,7 +293,7 @@ impl<'tcx> Const<'tcx> {
     /// Normalizes the constant to a value or an error if possible.
     #[inline]
     pub fn normalize(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> Self {
-        match self.eval(tcx, param_env, None) {
+        match self.eval(tcx, param_env, DUMMY_SP) {
             Ok(val) => Self::Val(val, self.ty()),
             Err(ErrorHandled::Reported(guar, _span)) => {
                 Self::Ty(ty::Const::new_error(tcx, guar.into(), self.ty()))
@@ -313,10 +313,10 @@ impl<'tcx> Const<'tcx> {
                 // Avoid the `valtree_to_const_val` query. Can only be done on primitive types that
                 // are valtree leaves, and *not* on references. (References should return the
                 // pointer here, which valtrees don't represent.)
-                let val = c.eval(tcx, param_env, None).ok()?;
+                let val = c.eval(tcx, param_env, DUMMY_SP).ok()?;
                 Some(val.unwrap_leaf().into())
             }
-            _ => self.eval(tcx, param_env, None).ok()?.try_to_scalar(),
+            _ => self.eval(tcx, param_env, DUMMY_SP).ok()?.try_to_scalar(),
         }
     }
 
diff --git a/compiler/rustc_middle/src/mir/interpret/queries.rs b/compiler/rustc_middle/src/mir/interpret/queries.rs
index 643b61c1de3d7..04d6301116eea 100644
--- a/compiler/rustc_middle/src/mir/interpret/queries.rs
+++ b/compiler/rustc_middle/src/mir/interpret/queries.rs
@@ -24,7 +24,7 @@ impl<'tcx> TyCtxt<'tcx> {
         let instance = ty::Instance::new(def_id, args);
         let cid = GlobalId { instance, promoted: None };
         let param_env = self.param_env(def_id).with_reveal_all_normalized(self);
-        self.const_eval_global_id(param_env, cid, None)
+        self.const_eval_global_id(param_env, cid, DUMMY_SP)
     }
     /// Resolves and evaluates a constant.
     ///
@@ -40,7 +40,7 @@ impl<'tcx> TyCtxt<'tcx> {
         self,
         param_env: ty::ParamEnv<'tcx>,
         ct: mir::UnevaluatedConst<'tcx>,
-        span: Option<Span>,
+        span: Span,
     ) -> EvalToConstValueResult<'tcx> {
         // Cannot resolve `Unevaluated` constants that contain inference
         // variables. We reject those here since `resolve`
@@ -73,7 +73,7 @@ impl<'tcx> TyCtxt<'tcx> {
         self,
         param_env: ty::ParamEnv<'tcx>,
         ct: ty::UnevaluatedConst<'tcx>,
-        span: Option<Span>,
+        span: Span,
     ) -> EvalToValTreeResult<'tcx> {
         // Cannot resolve `Unevaluated` constants that contain inference
         // variables. We reject those here since `resolve`
@@ -130,7 +130,7 @@ impl<'tcx> TyCtxt<'tcx> {
         self,
         param_env: ty::ParamEnv<'tcx>,
         instance: ty::Instance<'tcx>,
-        span: Option<Span>,
+        span: Span,
     ) -> EvalToConstValueResult<'tcx> {
         self.const_eval_global_id(param_env, GlobalId { instance, promoted: None }, span)
     }
@@ -141,12 +141,12 @@ impl<'tcx> TyCtxt<'tcx> {
         self,
         param_env: ty::ParamEnv<'tcx>,
         cid: GlobalId<'tcx>,
-        span: Option<Span>,
+        span: Span,
     ) -> EvalToConstValueResult<'tcx> {
         // Const-eval shouldn't depend on lifetimes at all, so we can erase them, which should
         // improve caching of queries.
         let inputs = self.erase_regions(param_env.with_reveal_all_normalized(self).and(cid));
-        if let Some(span) = span {
+        if !span.is_dummy() {
             // The query doesn't know where it is being invoked, so we need to fix the span.
             self.at(span).eval_to_const_value_raw(inputs).map_err(|e| e.with_span(span))
         } else {
@@ -160,13 +160,13 @@ impl<'tcx> TyCtxt<'tcx> {
         self,
         param_env: ty::ParamEnv<'tcx>,
         cid: GlobalId<'tcx>,
-        span: Option<Span>,
+        span: Span,
     ) -> EvalToValTreeResult<'tcx> {
         // Const-eval shouldn't depend on lifetimes at all, so we can erase them, which should
         // improve caching of queries.
         let inputs = self.erase_regions(param_env.with_reveal_all_normalized(self).and(cid));
         debug!(?inputs);
-        if let Some(span) = span {
+        if !span.is_dummy() {
             // The query doesn't know where it is being invoked, so we need to fix the span.
             self.at(span).eval_to_valtree(inputs).map_err(|e| e.with_span(span))
         } else {
diff --git a/compiler/rustc_middle/src/ty/consts.rs b/compiler/rustc_middle/src/ty/consts.rs
index 5b62c0bf931af..0d621cd1cfd9b 100644
--- a/compiler/rustc_middle/src/ty/consts.rs
+++ b/compiler/rustc_middle/src/ty/consts.rs
@@ -335,7 +335,7 @@ impl<'tcx> Const<'tcx> {
         self,
         tcx: TyCtxt<'tcx>,
         param_env: ParamEnv<'tcx>,
-        span: Option<Span>,
+        span: Span,
     ) -> Result<ValTree<'tcx>, ErrorHandled> {
         assert!(!self.has_escaping_bound_vars(), "escaping vars in {self:?}");
         match self.kind() {
@@ -349,7 +349,7 @@ impl<'tcx> Const<'tcx> {
                 else {
                     // This can happen when we run on ill-typed code.
                     let e = tcx.dcx().span_delayed_bug(
-                        span.unwrap_or(DUMMY_SP),
+                        span,
                         "`ty::Const::eval` called on a non-valtree-compatible type",
                     );
                     return Err(e.into());
@@ -362,14 +362,14 @@ impl<'tcx> Const<'tcx> {
             | ConstKind::Infer(_)
             | ConstKind::Bound(_, _)
             | ConstKind::Placeholder(_)
-            | ConstKind::Expr(_) => Err(ErrorHandled::TooGeneric(span.unwrap_or(DUMMY_SP))),
+            | ConstKind::Expr(_) => Err(ErrorHandled::TooGeneric(span)),
         }
     }
 
     /// Normalizes the constant to a value or an error if possible.
     #[inline]
     pub fn normalize(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Self {
-        match self.eval(tcx, param_env, None) {
+        match self.eval(tcx, param_env, DUMMY_SP) {
             Ok(val) => Self::new_value(tcx, val, self.ty()),
             Err(ErrorHandled::Reported(r, _span)) => Self::new_error(tcx, r.into(), self.ty()),
             Err(ErrorHandled::TooGeneric(_span)) => self,
@@ -382,7 +382,7 @@ impl<'tcx> Const<'tcx> {
         tcx: TyCtxt<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
     ) -> Option<Scalar> {
-        self.eval(tcx, param_env, None).ok()?.try_to_scalar()
+        self.eval(tcx, param_env, DUMMY_SP).ok()?.try_to_scalar()
     }
 
     #[inline]
diff --git a/compiler/rustc_mir_build/src/thir/pattern/mod.rs b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
index ac3043afcff08..03eda9a932223 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/mod.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
@@ -524,12 +524,12 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         // Prefer valtrees over opaque constants.
         let const_value = self
             .tcx
-            .const_eval_global_id_for_typeck(param_env_reveal_all, cid, Some(span))
+            .const_eval_global_id_for_typeck(param_env_reveal_all, cid, span)
             .map(|val| match val {
                 Some(valtree) => mir::Const::Ty(ty::Const::new_value(self.tcx, valtree, ty)),
                 None => mir::Const::Val(
                     self.tcx
-                        .const_eval_global_id(param_env_reveal_all, cid, Some(span))
+                        .const_eval_global_id(param_env_reveal_all, cid, span)
                         .expect("const_eval_global_id_for_typeck should have already failed"),
                     ty,
                 ),
@@ -627,15 +627,14 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         // First try using a valtree in order to destructure the constant into a pattern.
         // FIXME: replace "try to do a thing, then fall back to another thing"
         // but something more principled, like a trait query checking whether this can be turned into a valtree.
-        if let Ok(Some(valtree)) =
-            self.tcx.const_eval_resolve_for_typeck(self.param_env, ct, Some(span))
+        if let Ok(Some(valtree)) = self.tcx.const_eval_resolve_for_typeck(self.param_env, ct, span)
         {
             let subpattern =
                 self.const_to_pat(Const::Ty(ty::Const::new_value(self.tcx, valtree, ty)), id, span);
             PatKind::InlineConstant { subpattern, def: def_id }
         } else {
             // If that fails, convert it to an opaque constant pattern.
-            match tcx.const_eval_resolve(self.param_env, uneval, Some(span)) {
+            match tcx.const_eval_resolve(self.param_env, uneval, span) {
                 Ok(val) => self.const_to_pat(mir::Const::Val(val, ty), id, span).kind,
                 Err(ErrorHandled::TooGeneric(_)) => {
                     // If we land here it means the const can't be evaluated because it's `TooGeneric`.
diff --git a/compiler/rustc_mir_transform/src/add_retag.rs b/compiler/rustc_mir_transform/src/add_retag.rs
index 6f668aa4ce850..f880476cec2f2 100644
--- a/compiler/rustc_mir_transform/src/add_retag.rs
+++ b/compiler/rustc_mir_transform/src/add_retag.rs
@@ -24,7 +24,7 @@ fn may_contain_reference<'tcx>(ty: Ty<'tcx>, depth: u32, tcx: TyCtxt<'tcx>) -> b
         | ty::Str
         | ty::FnDef(..)
         | ty::Never => false,
-        // References
+        // References and Boxes (`noalias` sources)
         ty::Ref(..) => true,
         ty::Adt(..) if ty.is_box() => true,
         ty::Adt(adt, _) if Some(adt.did()) == tcx.lang_items().ptr_unique() => true,
@@ -125,15 +125,39 @@ impl<'tcx> MirPass<'tcx> for AddRetag {
             for i in (0..block_data.statements.len()).rev() {
                 let (retag_kind, place) = match block_data.statements[i].kind {
                     // Retag after assignments of reference type.
-                    StatementKind::Assign(box (ref place, ref rvalue)) if needs_retag(place) => {
+                    StatementKind::Assign(box (ref place, ref rvalue)) => {
                         let add_retag = match rvalue {
                             // Ptr-creating operations already do their own internal retagging, no
                             // need to also add a retag statement.
-                            Rvalue::Ref(..) | Rvalue::AddressOf(..) => false,
-                            _ => true,
+                            // *Except* if we are deref'ing a Box, because those get desugared to directly working
+                            // with the inner raw pointer! That's relevant for `AddressOf` as Miri otherwise makes it
+                            // a NOP when the original pointer is already raw.
+                            Rvalue::AddressOf(_mutbl, place) => {
+                                // Using `is_box_global` here is a bit sketchy: if this code is
+                                // generic over the allocator, we'll not add a retag! This is a hack
+                                // to make Stacked Borrows compatible with custom allocator code.
+                                // Long-term, we'll want to move to an aliasing model where "cast to
+                                // raw pointer" is a complete NOP, and then this will no longer be
+                                // an issue.
+                                if place.is_indirect_first_projection()
+                                    && body.local_decls[place.local].ty.is_box_global(tcx)
+                                {
+                                    Some(RetagKind::Raw)
+                                } else {
+                                    None
+                                }
+                            }
+                            Rvalue::Ref(..) => None,
+                            _ => {
+                                if needs_retag(place) {
+                                    Some(RetagKind::Default)
+                                } else {
+                                    None
+                                }
+                            }
                         };
-                        if add_retag {
-                            (RetagKind::Default, *place)
+                        if let Some(kind) = add_retag {
+                            (kind, *place)
                         } else {
                             continue;
                         }
diff --git a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
index f456196b2822d..3389305e7eee7 100644
--- a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
+++ b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
@@ -394,7 +394,7 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
             }
             Operand::Constant(box constant) => {
                 if let Ok(constant) =
-                    self.ecx.eval_mir_constant(&constant.const_, Some(constant.span), None)
+                    self.ecx.eval_mir_constant(&constant.const_, constant.span, None)
                 {
                     self.assign_constant(state, place, constant, &[]);
                 }
diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs
index a3a2108787a73..87dff49e0be65 100644
--- a/compiler/rustc_mir_transform/src/gvn.rs
+++ b/compiler/rustc_mir_transform/src/gvn.rs
@@ -367,7 +367,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
             Repeat(..) => return None,
 
             Constant { ref value, disambiguator: _ } => {
-                self.ecx.eval_mir_constant(value, None, None).ok()?
+                self.ecx.eval_mir_constant(value, DUMMY_SP, None).ok()?
             }
             Aggregate(kind, variant, ref fields) => {
                 let fields = fields
diff --git a/compiler/rustc_mir_transform/src/jump_threading.rs b/compiler/rustc_mir_transform/src/jump_threading.rs
index 6629face94041..116d6f4845660 100644
--- a/compiler/rustc_mir_transform/src/jump_threading.rs
+++ b/compiler/rustc_mir_transform/src/jump_threading.rs
@@ -417,7 +417,7 @@ impl<'tcx, 'a> TOFinder<'tcx, 'a> {
             // If we expect `lhs ?= A`, we have an opportunity if we assume `constant == A`.
             Operand::Constant(constant) => {
                 let constant =
-                    self.ecx.eval_mir_constant(&constant.const_, Some(constant.span), None).ok()?;
+                    self.ecx.eval_mir_constant(&constant.const_, constant.span, None).ok()?;
                 self.process_constant(bb, lhs, constant, state);
             }
             // Transfer the conditions on the copied rhs.
diff --git a/compiler/rustc_mir_transform/src/known_panics_lint.rs b/compiler/rustc_mir_transform/src/known_panics_lint.rs
index 4bca437ea6f27..f19b78a3a5cd2 100644
--- a/compiler/rustc_mir_transform/src/known_panics_lint.rs
+++ b/compiler/rustc_mir_transform/src/known_panics_lint.rs
@@ -261,7 +261,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
         // manually normalized.
         let val = self.tcx.try_normalize_erasing_regions(self.param_env, c.const_).ok()?;
 
-        self.use_ecx(|this| this.ecx.eval_mir_constant(&val, Some(c.span), None))?
+        self.use_ecx(|this| this.ecx.eval_mir_constant(&val, c.span, None))?
             .as_mplace_or_imm()
             .right()
     }
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index 3e5ec323d2746..afe228be12797 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -529,11 +529,11 @@ fn run_runtime_lowering_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         // AddMovesForPackedDrops needs to run after drop
         // elaboration.
         &add_moves_for_packed_drops::AddMovesForPackedDrops,
-        // `AddRetag` needs to run after `ElaborateDrops`. Otherwise it should run fairly late,
+        // `AddRetag` needs to run after `ElaborateDrops` but before `ElaborateBoxDerefs`. Otherwise it should run fairly late,
         // but before optimizations begin.
+        &add_retag::AddRetag,
         &elaborate_box_derefs::ElaborateBoxDerefs,
         &coroutine::StateTransform,
-        &add_retag::AddRetag,
         &Lint(known_panics_lint::KnownPanicsLint),
     ];
     pm::run_passes_no_validate(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::Initial)));
diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
index dd8cb6127be96..d8bdbd8c442b0 100644
--- a/compiler/rustc_monomorphize/src/collector.rs
+++ b/compiler/rustc_monomorphize/src/collector.rs
@@ -828,7 +828,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
         // a codegen-time error). rustc stops after collection if there was an error, so this
         // ensures codegen never has to worry about failing consts.
         // (codegen relies on this and ICEs will happen if this is violated.)
-        let val = match const_.eval(self.tcx, param_env, Some(constant.span)) {
+        let val = match const_.eval(self.tcx, param_env, constant.span) {
             Ok(v) => v,
             Err(ErrorHandled::TooGeneric(..)) => span_bug!(
                 self.body.source_info(location).span,
diff --git a/compiler/rustc_smir/src/rustc_smir/builder.rs b/compiler/rustc_smir/src/rustc_smir/builder.rs
index a13262cdcc494..0762016ef75b3 100644
--- a/compiler/rustc_smir/src/rustc_smir/builder.rs
+++ b/compiler/rustc_smir/src/rustc_smir/builder.rs
@@ -56,7 +56,7 @@ impl<'tcx> MutVisitor<'tcx> for BodyBuilder<'tcx> {
 
     fn visit_constant(&mut self, constant: &mut mir::ConstOperand<'tcx>, location: mir::Location) {
         let const_ = self.monomorphize(constant.const_);
-        let val = match const_.eval(self.tcx, ty::ParamEnv::reveal_all(), Some(constant.span)) {
+        let val = match const_.eval(self.tcx, ty::ParamEnv::reveal_all(), constant.span) {
             Ok(v) => v,
             Err(mir::interpret::ErrorHandled::Reported(..)) => return,
             Err(mir::interpret::ErrorHandled::TooGeneric(..)) => {
diff --git a/compiler/rustc_smir/src/rustc_smir/context.rs b/compiler/rustc_smir/src/rustc_smir/context.rs
index 509f0def2568e..d427e5fb88d61 100644
--- a/compiler/rustc_smir/src/rustc_smir/context.rs
+++ b/compiler/rustc_smir/src/rustc_smir/context.rs
@@ -566,7 +566,7 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         let result = tcx.const_eval_instance(
             ParamEnv::reveal_all(),
             instance,
-            Some(tcx.def_span(instance.def_id())),
+            tcx.def_span(instance.def_id()),
         );
         result
             .map(|const_val| {
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index e43c9533382e1..63b950a2803c4 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1463,7 +1463,6 @@ symbols! {
         residual,
         result,
         resume,
-        retag_box_to_raw,
         return_position_impl_trait_in_trait,
         return_type_notation,
         rhs,
diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
index 3b858cb449fa1..a4ee0e03e6556 100644
--- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
@@ -968,7 +968,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         ty: Ty<'tcx>,
     ) -> Option<ty::Const<'tcx>> {
         use rustc_middle::mir::interpret::ErrorHandled;
-        match self.infcx.try_const_eval_resolve(param_env, unevaluated, ty, None) {
+        match self.infcx.try_const_eval_resolve(param_env, unevaluated, ty, DUMMY_SP) {
             Ok(ct) => Some(ct),
             Err(ErrorHandled::Reported(e, _)) => {
                 Some(ty::Const::new_error(self.tcx(), e.into(), ty))
diff --git a/compiler/rustc_trait_selection/src/traits/auto_trait.rs b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
index fbf96833187d8..0796ffcbc45a0 100644
--- a/compiler/rustc_trait_selection/src/traits/auto_trait.rs
+++ b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
@@ -786,7 +786,7 @@ impl<'tcx> AutoTraitFinder<'tcx> {
                             match selcx.infcx.const_eval_resolve(
                                 obligation.param_env,
                                 unevaluated,
-                                Some(obligation.cause.span),
+                                obligation.cause.span,
                             ) {
                                 Ok(Some(valtree)) => Ok(ty::Const::new_value(selcx.tcx(),valtree, c.ty())),
                                 Ok(None) => {
diff --git a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
index 7f0f9a12d6a05..9ca1dd4557dc8 100644
--- a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
+++ b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
@@ -68,7 +68,7 @@ pub fn is_const_evaluatable<'tcx>(
                 tcx.dcx().span_bug(span, "evaluating `ConstKind::Expr` is not currently supported");
             }
             ty::ConstKind::Unevaluated(uv) => {
-                let concrete = infcx.const_eval_resolve(param_env, uv, Some(span));
+                let concrete = infcx.const_eval_resolve(param_env, uv, span);
                 match concrete {
                     Err(ErrorHandled::TooGeneric(_)) => {
                         Err(NotConstEvaluatable::Error(infcx.dcx().span_delayed_bug(
@@ -99,7 +99,7 @@ pub fn is_const_evaluatable<'tcx>(
         // and hopefully soon change this to an error.
         //
         // See #74595 for more details about this.
-        let concrete = infcx.const_eval_resolve(param_env, uv, Some(span));
+        let concrete = infcx.const_eval_resolve(param_env, uv, span);
         match concrete {
             // If we're evaluating a generic foreign constant, under a nightly compiler while
             // the current crate does not enable `feature(generic_const_exprs)`, abort
diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs
index 2fd64f474d5ad..34c891d400e45 100644
--- a/compiler/rustc_trait_selection/src/traits/fulfill.rs
+++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs
@@ -600,7 +600,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                                 obligation.param_env,
                                 unevaluated,
                                 c.ty(),
-                                Some(obligation.cause.span),
+                                obligation.cause.span,
                             ) {
                                 Ok(val) => Ok(val),
                                 Err(e) => {
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index d10fe6a949013..be71eac6948a6 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -949,7 +949,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                 obligation.param_env,
                                 unevaluated,
                                 c.ty(),
-                                Some(obligation.cause.span),
+                                obligation.cause.span,
                             ) {
                                 Ok(val) => Ok(val),
                                 Err(e) => Err(e),
diff --git a/compiler/rustc_transmute/src/lib.rs b/compiler/rustc_transmute/src/lib.rs
index e871c4659b4b9..b6f937ebe472b 100644
--- a/compiler/rustc_transmute/src/lib.rs
+++ b/compiler/rustc_transmute/src/lib.rs
@@ -89,6 +89,7 @@ mod rustc {
     use rustc_middle::ty::Ty;
     use rustc_middle::ty::TyCtxt;
     use rustc_middle::ty::ValTree;
+    use rustc_span::DUMMY_SP;
 
     /// The source and destination types of a transmutation.
     #[derive(TypeVisitable, Debug, Clone, Copy)]
@@ -135,7 +136,7 @@ mod rustc {
             use rustc_middle::ty::ScalarInt;
             use rustc_span::symbol::sym;
 
-            let Ok(cv) = c.eval(tcx, param_env, None) else {
+            let Ok(cv) = c.eval(tcx, param_env, DUMMY_SP) else {
                 return Some(Self {
                     alignment: true,
                     lifetimes: true,
diff --git a/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs
index 304f607000b01..f47fe560b07a2 100644
--- a/library/alloc/src/boxed.rs
+++ b/library/alloc/src/boxed.rs
@@ -155,7 +155,6 @@ use core::error::Error;
 use core::fmt;
 use core::future::Future;
 use core::hash::{Hash, Hasher};
-use core::intrinsics::retag_box_to_raw;
 use core::iter::FusedIterator;
 use core::marker::Tuple;
 use core::marker::Unsize;
@@ -165,7 +164,7 @@ use core::ops::{
     CoerceUnsized, Coroutine, CoroutineState, Deref, DerefMut, DispatchFromDyn, Receiver,
 };
 use core::pin::Pin;
-use core::ptr::{self, NonNull, Unique};
+use core::ptr::{self, addr_of_mut, NonNull, Unique};
 use core::task::{Context, Poll};
 
 #[cfg(not(no_global_oom_handling))]
@@ -1111,16 +1110,12 @@ impl<T: ?Sized, A: Allocator> Box<T, A> {
     #[unstable(feature = "allocator_api", issue = "32838")]
     #[inline]
     pub fn into_raw_with_allocator(b: Self) -> (*mut T, A) {
-        // This is the transition point from `Box` to raw pointers. For Stacked Borrows, these casts
-        // are relevant -- if this is a global allocator Box and we just get the pointer from `b.0`,
-        // it will have `Unique` permission, which is not what we want from a raw pointer. We could
-        // fix that by going through `&mut`, but then if this is *not* a global allocator Box, we'd
-        // be adding uniqueness assertions that we do not want. So for Miri's sake we pass this
-        // pointer through an intrinsic for box-to-raw casts, which can do the right thing wrt the
-        // aliasing model.
-        let b = mem::ManuallyDrop::new(b);
+        let mut b = mem::ManuallyDrop::new(b);
+        // We carefully get the raw pointer out in a way that Miri's aliasing model understands what
+        // is happening: using the primitive "deref" of `Box`.
+        let ptr = addr_of_mut!(**b);
         let alloc = unsafe { ptr::read(&b.1) };
-        (unsafe { retag_box_to_raw::<T, A>(b.0.as_ptr()) }, alloc)
+        (ptr, alloc)
     }
 
     #[unstable(
diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs
index 86b9a39d68a67..f939720287fd4 100644
--- a/library/core/src/intrinsics.rs
+++ b/library/core/src/intrinsics.rs
@@ -2709,19 +2709,6 @@ pub unsafe fn vtable_size(_ptr: *const ()) -> usize {
     unreachable!()
 }
 
-/// Retag a box pointer as part of casting it to a raw pointer. This is the `Box` equivalent of
-/// `(x: &mut T) as *mut T`. The input pointer must be the pointer of a `Box` (passed as raw pointer
-/// to avoid all questions around move semantics and custom allocators), and `A` must be the `Box`'s
-/// allocator.
-#[unstable(feature = "core_intrinsics", issue = "none")]
-#[rustc_nounwind]
-#[cfg_attr(not(bootstrap), rustc_intrinsic)]
-#[cfg_attr(bootstrap, inline)]
-pub unsafe fn retag_box_to_raw<T: ?Sized, A>(ptr: *mut T) -> *mut T {
-    // Miri needs to adjust the provenance, but for regular codegen this is not needed
-    ptr
-}
-
 // Some functions are defined here because they accidentally got made
 // available in this module on stable. See <https://github.com/rust-lang/rust/issues/15702>.
 // (`transmute` also falls into this category, but it cannot be wrapped due to the
diff --git a/src/bootstrap/src/core/build_steps/llvm.rs b/src/bootstrap/src/core/build_steps/llvm.rs
index 701bd585eee76..3da927b5fa0fa 100644
--- a/src/bootstrap/src/core/build_steps/llvm.rs
+++ b/src/bootstrap/src/core/build_steps/llvm.rs
@@ -564,11 +564,11 @@ fn check_llvm_version(builder: &Builder<'_>, llvm_config: &Path) {
     let version = output(cmd.arg("--version"));
     let mut parts = version.split('.').take(2).filter_map(|s| s.parse::<u32>().ok());
     if let (Some(major), Some(_minor)) = (parts.next(), parts.next()) {
-        if major >= 16 {
+        if major >= 17 {
             return;
         }
     }
-    panic!("\n\nbad LLVM version: {version}, need >=16.0\n\n")
+    panic!("\n\nbad LLVM version: {version}, need >=17.0\n\n")
 }
 
 fn configure_cmake(
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-16/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-16/Dockerfile
deleted file mode 100644
index 4fc2b2e507e0d..0000000000000
--- a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-16/Dockerfile
+++ /dev/null
@@ -1,67 +0,0 @@
-FROM ubuntu:23.04
-
-ARG DEBIAN_FRONTEND=noninteractive
-
-RUN apt-get update && apt-get install -y --no-install-recommends \
-  g++ \
-  gcc-multilib \
-  make \
-  ninja-build \
-  file \
-  curl \
-  ca-certificates \
-  python3 \
-  git \
-  cmake \
-  sudo \
-  gdb \
-  llvm-16-tools \
-  llvm-16-dev \
-  libedit-dev \
-  libssl-dev \
-  pkg-config \
-  zlib1g-dev \
-  xz-utils \
-  nodejs \
-  mingw-w64 \
-  # libgccjit dependencies
-  flex \
-  libmpfr-dev \
-  libgmp-dev \
-  libmpc3 \
-  libmpc-dev \
-  && rm -rf /var/lib/apt/lists/*
-
-# Note: libgccjit needs to match the default gcc version for the linker to find it.
-
-# Install powershell (universal package) so we can test x.ps1 on Linux
-RUN curl -sL "https://github.com/PowerShell/PowerShell/releases/download/v7.3.1/powershell_7.3.1-1.deb_amd64.deb" > powershell.deb && \
-    dpkg -i powershell.deb && \
-    rm -f powershell.deb
-
-COPY scripts/sccache.sh /scripts/
-RUN sh /scripts/sccache.sh
-
-# We are disabling CI LLVM since this builder is intentionally using a host
-# LLVM, rather than the typical src/llvm-project LLVM.
-ENV NO_DOWNLOAD_CI_LLVM 1
-
-# This is not the latest LLVM version, so some components required by tests may
-# be missing.
-ENV IS_NOT_LATEST_LLVM 1
-
-# Using llvm-link-shared due to libffi issues -- see #34486
-ENV RUST_CONFIGURE_ARGS \
-      --build=x86_64-unknown-linux-gnu \
-      --llvm-root=/usr/lib/llvm-16 \
-      --enable-llvm-link-shared \
-      --set rust.thin-lto-import-instr-limit=10
-
-COPY host-x86_64/x86_64-gnu-llvm-16/script.sh /tmp/
-
-COPY host-x86_64/dist-x86_64-linux/shared.sh /scripts/
-COPY host-x86_64/dist-x86_64-linux/build-gccjit.sh /scripts/
-
-RUN /scripts/build-gccjit.sh /scripts
-
-ENV SCRIPT /tmp/script.sh
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-17/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-17/Dockerfile
index 7c2ecd198e234..538962802c96f 100644
--- a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-17/Dockerfile
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-17/Dockerfile
@@ -56,11 +56,10 @@ ENV RUST_CONFIGURE_ARGS \
       --enable-llvm-link-shared \
       --set rust.thin-lto-import-instr-limit=10
 
-COPY host-x86_64/x86_64-gnu-llvm-16/script.sh /tmp/
-
 COPY host-x86_64/dist-x86_64-linux/shared.sh /scripts/
 COPY host-x86_64/dist-x86_64-linux/build-gccjit.sh /scripts/
 
 RUN /scripts/build-gccjit.sh /scripts
 
+COPY scripts/x86_64-gnu-llvm.sh /tmp/script.sh
 ENV SCRIPT /tmp/script.sh
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-18/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-18/Dockerfile
index e8383500dfc94..3476b10a3addc 100644
--- a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-18/Dockerfile
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-18/Dockerfile
@@ -24,11 +24,14 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   xz-utils \
   nodejs \
   mingw-w64 \
-  libgccjit-13-dev \
+  # libgccjit dependencies
+  flex \
+  libmpfr-dev \
+  libgmp-dev \
+  libmpc3 \
+  libmpc-dev \
   && rm -rf /var/lib/apt/lists/*
 
-# Note: libgccjit needs to match the default gcc version for the linker to find it.
-
 # Install powershell (universal package) so we can test x.ps1 on Linux
 # FIXME: need a "universal" version that supports libicu74, but for now it still works to ignore that dep.
 RUN curl -sL "https://github.com/PowerShell/PowerShell/releases/download/v7.3.1/powershell_7.3.1-1.deb_amd64.deb" > powershell.deb && \
@@ -50,6 +53,10 @@ ENV RUST_CONFIGURE_ARGS \
       --enable-llvm-link-shared \
       --set rust.thin-lto-import-instr-limit=10
 
-COPY host-x86_64/x86_64-gnu-llvm-16/script.sh /tmp/
+COPY host-x86_64/dist-x86_64-linux/shared.sh /scripts/
+COPY host-x86_64/dist-x86_64-linux/build-gccjit.sh /scripts/
+
+RUN /scripts/build-gccjit.sh /scripts
 
+COPY scripts/x86_64-gnu-llvm.sh /tmp/script.sh
 ENV SCRIPT /tmp/script.sh
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-16/script.sh b/src/ci/docker/scripts/x86_64-gnu-llvm.sh
similarity index 100%
rename from src/ci/docker/host-x86_64/x86_64-gnu-llvm-16/script.sh
rename to src/ci/docker/scripts/x86_64-gnu-llvm.sh
diff --git a/src/ci/github-actions/ci.yml b/src/ci/github-actions/ci.yml
index bc81b1e04a764..972ef35933749 100644
--- a/src/ci/github-actions/ci.yml
+++ b/src/ci/github-actions/ci.yml
@@ -357,7 +357,7 @@ jobs:
           - name: mingw-check-tidy
             <<: *job-linux-4c
 
-          - name: x86_64-gnu-llvm-16
+          - name: x86_64-gnu-llvm-17
             env:
               ENABLE_GCC_CODEGEN: "1"
             <<: *job-linux-16c
@@ -520,11 +520,6 @@ jobs:
               RUST_BACKTRACE: 1
             <<: *job-linux-8c
 
-          - name: x86_64-gnu-llvm-16
-            env:
-              RUST_BACKTRACE: 1
-            <<: *job-linux-8c
-
           - name: x86_64-gnu-nopt
             <<: *job-linux-4c
 
diff --git a/src/tools/clippy/clippy_lints/src/non_copy_const.rs b/src/tools/clippy/clippy_lints/src/non_copy_const.rs
index ea73d9afa2ea0..cebd23856565d 100644
--- a/src/tools/clippy/clippy_lints/src/non_copy_const.rs
+++ b/src/tools/clippy/clippy_lints/src/non_copy_const.rs
@@ -290,14 +290,14 @@ impl NonCopyConst {
             promoted: None,
         };
         let param_env = cx.tcx.param_env(def_id).with_reveal_all_normalized(cx.tcx);
-        let result = cx.tcx.const_eval_global_id_for_typeck(param_env, cid, None);
+        let result = cx.tcx.const_eval_global_id_for_typeck(param_env, cid, rustc_span::DUMMY_SP);
         self.is_value_unfrozen_raw(cx, result, ty)
     }
 
     fn is_value_unfrozen_expr<'tcx>(&self, cx: &LateContext<'tcx>, hir_id: HirId, def_id: DefId, ty: Ty<'tcx>) -> bool {
         let args = cx.typeck_results().node_args(hir_id);
 
-        let result = Self::const_eval_resolve(cx.tcx, cx.param_env, ty::UnevaluatedConst::new(def_id, args), None);
+        let result = Self::const_eval_resolve(cx.tcx, cx.param_env, ty::UnevaluatedConst::new(def_id, args), rustc_span::DUMMY_SP);
         self.is_value_unfrozen_raw(cx, result, ty)
     }
 
@@ -305,7 +305,7 @@ impl NonCopyConst {
         tcx: TyCtxt<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
         ct: ty::UnevaluatedConst<'tcx>,
-        span: Option<Span>,
+        span: Span,
     ) -> EvalToValTreeResult<'tcx> {
         match ty::Instance::resolve(tcx, param_env, ct.def, ct.args) {
             Ok(Some(instance)) => {
@@ -315,8 +315,8 @@ impl NonCopyConst {
                 };
                 tcx.const_eval_global_id_for_typeck(param_env, cid, span)
             },
-            Ok(None) => Err(ErrorHandled::TooGeneric(span.unwrap_or(rustc_span::DUMMY_SP))),
-            Err(err) => Err(ErrorHandled::Reported(err.into(), span.unwrap_or(rustc_span::DUMMY_SP))),
+            Ok(None) => Err(ErrorHandled::TooGeneric(span)),
+            Err(err) => Err(ErrorHandled::Reported(err.into(), span)),
         }
     }
 }
diff --git a/src/tools/clippy/clippy_utils/src/consts.rs b/src/tools/clippy/clippy_utils/src/consts.rs
index 07ed4fbbf8e9e..e75d5953faefd 100644
--- a/src/tools/clippy/clippy_utils/src/consts.rs
+++ b/src/tools/clippy/clippy_utils/src/consts.rs
@@ -550,7 +550,7 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
                 let result = self
                     .lcx
                     .tcx
-                    .const_eval_resolve(self.param_env, mir::UnevaluatedConst::new(def_id, args), None)
+                    .const_eval_resolve(self.param_env, mir::UnevaluatedConst::new(def_id, args), qpath.span())
                     .ok()
                     .map(|val| rustc_middle::mir::Const::from_value(val, ty))?;
                 let result = mir_to_const(self.lcx, result)?;
diff --git a/src/tools/miri/src/borrow_tracker/mod.rs b/src/tools/miri/src/borrow_tracker/mod.rs
index 0f7200fb4074a..8d76a488269fc 100644
--- a/src/tools/miri/src/borrow_tracker/mod.rs
+++ b/src/tools/miri/src/borrow_tracker/mod.rs
@@ -5,7 +5,7 @@ use std::num::NonZero;
 use smallvec::SmallVec;
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_middle::{mir::RetagKind, ty::Ty};
+use rustc_middle::mir::RetagKind;
 use rustc_target::abi::Size;
 
 use crate::*;
@@ -291,19 +291,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         }
     }
 
-    fn retag_box_to_raw(
-        &mut self,
-        val: &ImmTy<'tcx, Provenance>,
-        alloc_ty: Ty<'tcx>,
-    ) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
-        let this = self.eval_context_mut();
-        let method = this.machine.borrow_tracker.as_ref().unwrap().borrow().borrow_tracker_method;
-        match method {
-            BorrowTrackerMethod::StackedBorrows => this.sb_retag_box_to_raw(val, alloc_ty),
-            BorrowTrackerMethod::TreeBorrows => this.tb_retag_box_to_raw(val, alloc_ty),
-        }
-    }
-
     fn retag_place_contents(
         &mut self,
         kind: RetagKind,
diff --git a/src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs b/src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs
index 9130601bbddb9..7a6a85a2f7905 100644
--- a/src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs
+++ b/src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs
@@ -865,24 +865,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         this.sb_retag_reference(val, new_perm, RetagInfo { cause, in_field: false })
     }
 
-    fn sb_retag_box_to_raw(
-        &mut self,
-        val: &ImmTy<'tcx, Provenance>,
-        alloc_ty: Ty<'tcx>,
-    ) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
-        let this = self.eval_context_mut();
-        let is_global_alloc = alloc_ty.ty_adt_def().is_some_and(|adt| {
-            let global_alloc = this.tcx.require_lang_item(rustc_hir::LangItem::GlobalAlloc, None);
-            adt.did() == global_alloc
-        });
-        if is_global_alloc {
-            // Retag this as-if it was a mutable reference.
-            this.sb_retag_ptr_value(RetagKind::Raw, val)
-        } else {
-            Ok(val.clone())
-        }
-    }
-
     fn sb_retag_place_contents(
         &mut self,
         kind: RetagKind,
@@ -891,9 +873,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         let this = self.eval_context_mut();
         let retag_fields = this.machine.borrow_tracker.as_mut().unwrap().get_mut().retag_fields;
         let retag_cause = match kind {
-            RetagKind::Raw | RetagKind::TwoPhase { .. } => unreachable!(), // these can only happen in `retag_ptr_value`
+            RetagKind::TwoPhase { .. } => unreachable!(), // can only happen in `retag_ptr_value`
             RetagKind::FnEntry => RetagCause::FnEntry,
-            RetagKind::Default => RetagCause::Normal,
+            RetagKind::Default | RetagKind::Raw => RetagCause::Normal,
         };
         let mut visitor =
             RetagVisitor { ecx: this, kind, retag_cause, retag_fields, in_field: false };
@@ -959,14 +941,14 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
 
                 // Check the type of this value to see what to do with it (retag, or recurse).
                 match place.layout.ty.kind() {
-                    ty::Ref(..) => {
-                        let new_perm =
-                            NewPermission::from_ref_ty(place.layout.ty, self.kind, self.ecx);
-                        self.retag_ptr_inplace(place, new_perm)?;
-                    }
-                    ty::RawPtr(..) => {
-                        // We do *not* want to recurse into raw pointers -- wide raw pointers have
-                        // fields, and for dyn Trait pointees those can have reference type!
+                    ty::Ref(..) | ty::RawPtr(..) => {
+                        if matches!(place.layout.ty.kind(), ty::Ref(..))
+                            || self.kind == RetagKind::Raw
+                        {
+                            let new_perm =
+                                NewPermission::from_ref_ty(place.layout.ty, self.kind, self.ecx);
+                            self.retag_ptr_inplace(place, new_perm)?;
+                        }
                     }
                     ty::Adt(adt, _) if adt.is_box() => {
                         // Recurse for boxes, they require some tricky handling and will end up in `visit_box` above.
diff --git a/src/tools/miri/src/borrow_tracker/tree_borrows/mod.rs b/src/tools/miri/src/borrow_tracker/tree_borrows/mod.rs
index 9eb78b08ef77d..80bdcbb7559f2 100644
--- a/src/tools/miri/src/borrow_tracker/tree_borrows/mod.rs
+++ b/src/tools/miri/src/borrow_tracker/tree_borrows/mod.rs
@@ -392,15 +392,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         }
     }
 
-    fn tb_retag_box_to_raw(
-        &mut self,
-        val: &ImmTy<'tcx, Provenance>,
-        _alloc_ty: Ty<'tcx>,
-    ) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
-        // Casts to raw pointers are NOPs in Tree Borrows.
-        Ok(val.clone())
-    }
-
     /// Retag all pointers that are stored in this place.
     fn tb_retag_place_contents(
         &mut self,
diff --git a/src/tools/miri/src/machine.rs b/src/tools/miri/src/machine.rs
index 7e5518392d8a7..3a4ab32e4ab8a 100644
--- a/src/tools/miri/src/machine.rs
+++ b/src/tools/miri/src/machine.rs
@@ -1503,7 +1503,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
     fn eval_mir_constant<F>(
         ecx: &InterpCx<'mir, 'tcx, Self>,
         val: mir::Const<'tcx>,
-        span: Option<Span>,
+        span: Span,
         layout: Option<TyAndLayout<'tcx>>,
         eval: F,
     ) -> InterpResult<'tcx, OpTy<'tcx, Self::Provenance>>
@@ -1511,7 +1511,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
         F: Fn(
             &InterpCx<'mir, 'tcx, Self>,
             mir::Const<'tcx>,
-            Option<Span>,
+            Span,
             Option<TyAndLayout<'tcx>>,
         ) -> InterpResult<'tcx, OpTy<'tcx, Self::Provenance>>,
     {
diff --git a/src/tools/miri/src/shims/intrinsics/mod.rs b/src/tools/miri/src/shims/intrinsics/mod.rs
index 976d4b4de55cb..d16d5d99e9c01 100644
--- a/src/tools/miri/src/shims/intrinsics/mod.rs
+++ b/src/tools/miri/src/shims/intrinsics/mod.rs
@@ -140,18 +140,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
 
                 this.write_pointer(Pointer::new(ptr.provenance, masked_addr), dest)?;
             }
-            "retag_box_to_raw" => {
-                let [ptr] = check_arg_count(args)?;
-                let alloc_ty = generic_args[1].expect_ty();
-
-                let val = this.read_immediate(ptr)?;
-                let new_val = if this.machine.borrow_tracker.is_some() {
-                    this.retag_box_to_raw(&val, alloc_ty)?
-                } else {
-                    val
-                };
-                this.write_immediate(*new_val, dest)?;
-            }
 
             // We want to return either `true` or `false` at random, or else something like
             // ```
diff --git a/src/tools/miri/src/shims/intrinsics/simd.rs b/src/tools/miri/src/shims/intrinsics/simd.rs
index ddddcdcebd2af..c97a052f51715 100644
--- a/src/tools/miri/src/shims/intrinsics/simd.rs
+++ b/src/tools/miri/src/shims/intrinsics/simd.rs
@@ -549,7 +549,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
 
                 let index = generic_args[2]
                     .expect_const()
-                    .eval(*this.tcx, this.param_env(), Some(this.tcx.span))
+                    .eval(*this.tcx, this.param_env(), this.tcx.span)
                     .unwrap()
                     .unwrap_branch();
                 let index_len = index.len();
diff --git a/src/tools/miri/tests/fail/both_borrows/newtype_pair_retagging.stack.stderr b/src/tools/miri/tests/fail/both_borrows/newtype_pair_retagging.stack.stderr
index c26c7f397b09f..867907e98e66f 100644
--- a/src/tools/miri/tests/fail/both_borrows/newtype_pair_retagging.stack.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/newtype_pair_retagging.stack.stderr
@@ -6,7 +6,7 @@ LL |         Box(unsafe { Unique::new_unchecked(raw) }, alloc)
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
-help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
   --> $DIR/newtype_pair_retagging.rs:LL:CC
    |
 LL |     let ptr = Box::into_raw(Box::new(0i32));
diff --git a/src/tools/miri/tests/fail/both_borrows/newtype_retagging.stack.stderr b/src/tools/miri/tests/fail/both_borrows/newtype_retagging.stack.stderr
index ae54da70fe2d8..56715938e9788 100644
--- a/src/tools/miri/tests/fail/both_borrows/newtype_retagging.stack.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/newtype_retagging.stack.stderr
@@ -6,7 +6,7 @@ LL |         Box(unsafe { Unique::new_unchecked(raw) }, alloc)
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
-help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
   --> $DIR/newtype_retagging.rs:LL:CC
    |
 LL |     let ptr = Box::into_raw(Box::new(0i32));
diff --git a/tests/codegen/issues/issue-114312.rs b/tests/codegen/issues/issue-114312.rs
index 54fa40dcf0d49..be5b999afd0b0 100644
--- a/tests/codegen/issues/issue-114312.rs
+++ b/tests/codegen/issues/issue-114312.rs
@@ -1,5 +1,4 @@
 //@ compile-flags: -O
-//@ min-llvm-version: 17
 //@ only-x86_64-unknown-linux-gnu
 
 // We want to check that this function does not mis-optimize to loop jumping.
diff --git a/tests/codegen/move-before-nocapture-ref-arg.rs b/tests/codegen/move-before-nocapture-ref-arg.rs
index a530bc266729a..c3448192ea173 100644
--- a/tests/codegen/move-before-nocapture-ref-arg.rs
+++ b/tests/codegen/move-before-nocapture-ref-arg.rs
@@ -1,7 +1,6 @@
 // Verify that move before the call of the function with noalias, nocapture, readonly.
 // #107436
 //@ compile-flags: -O
-//@ min-llvm-version: 17
 
 #![crate_type = "lib"]
 
diff --git a/tests/codegen/option-as-slice.rs b/tests/codegen/option-as-slice.rs
index 14a3924360786..c5b1eafaccb74 100644
--- a/tests/codegen/option-as-slice.rs
+++ b/tests/codegen/option-as-slice.rs
@@ -1,7 +1,5 @@
 //@ compile-flags: -O -Z randomize-layout=no
 //@ only-x86_64
-//@ ignore-llvm-version: 16.0.0
-//  ^-- needs https://reviews.llvm.org/D146149 in 16.0.1
 #![crate_type = "lib"]
 #![feature(generic_nonzero)]
 
diff --git a/tests/codegen/trailing_zeros.rs b/tests/codegen/trailing_zeros.rs
index 66560c0d4fc47..b659e061821ea 100644
--- a/tests/codegen/trailing_zeros.rs
+++ b/tests/codegen/trailing_zeros.rs
@@ -1,5 +1,4 @@
 //@ compile-flags: -O
-//@ min-llvm-version: 17
 
 #![crate_type = "lib"]
 
diff --git a/tests/codegen/vec-shrink-panik.rs b/tests/codegen/vec-shrink-panik.rs
index 4e996b234f98d..4b798fe6c9cba 100644
--- a/tests/codegen/vec-shrink-panik.rs
+++ b/tests/codegen/vec-shrink-panik.rs
@@ -1,8 +1,5 @@
-//@ revisions: old new
 // LLVM 17 realizes double panic is not possible and doesn't generate calls
 // to panic_cannot_unwind.
-//@ [old]ignore-llvm-version: 17 - 99
-//@ [new]min-llvm-version: 17
 //@ compile-flags: -O
 //@ ignore-debug: plain old debug assertions
 //@ needs-unwind
@@ -22,14 +19,6 @@ pub fn shrink_to_fit(vec: &mut Vec<u32>) {
 // CHECK-LABEL: @issue71861
 #[no_mangle]
 pub fn issue71861(vec: Vec<u32>) -> Box<[u32]> {
-    // CHECK-NOT: panic
-
-    // Call to panic_cannot_unwind in case of double-panic is expected
-    // on LLVM 16 and older, but other panics are not.
-    // old: filter
-    // old-NEXT: ; call core::panicking::panic_cannot_unwind
-    // old-NEXT: panic_cannot_unwind
-
     // CHECK-NOT: panic
     vec.into_boxed_slice()
 }
@@ -40,6 +29,3 @@ pub fn issue75636<'a>(iter: &[&'a str]) -> Box<[&'a str]> {
     // CHECK-NOT: panic
     iter.iter().copied().collect()
 }
-
-// old: ; core::panicking::panic_cannot_unwind
-// old: declare void @{{.*}}panic_cannot_unwind
diff --git a/tests/mir-opt/retag.box_to_raw_mut.SimplifyCfg-pre-optimizations.after.panic-abort.mir b/tests/mir-opt/retag.box_to_raw_mut.SimplifyCfg-pre-optimizations.after.panic-abort.mir
new file mode 100644
index 0000000000000..0e568f6a5685f
--- /dev/null
+++ b/tests/mir-opt/retag.box_to_raw_mut.SimplifyCfg-pre-optimizations.after.panic-abort.mir
@@ -0,0 +1,17 @@
+// MIR for `box_to_raw_mut` after SimplifyCfg-pre-optimizations
+
+fn box_to_raw_mut(_1: &mut Box<i32>) -> *mut i32 {
+    debug x => _1;
+    let mut _0: *mut i32;
+    let mut _2: std::boxed::Box<i32>;
+    let mut _3: *const i32;
+
+    bb0: {
+        Retag([fn entry] _1);
+        _2 = deref_copy (*_1);
+        _3 = (((_2.0: std::ptr::Unique<i32>).0: std::ptr::NonNull<i32>).0: *const i32);
+        _0 = &raw mut (*_3);
+        Retag([raw] _0);
+        return;
+    }
+}
diff --git a/tests/mir-opt/retag.box_to_raw_mut.SimplifyCfg-pre-optimizations.after.panic-unwind.mir b/tests/mir-opt/retag.box_to_raw_mut.SimplifyCfg-pre-optimizations.after.panic-unwind.mir
new file mode 100644
index 0000000000000..0e568f6a5685f
--- /dev/null
+++ b/tests/mir-opt/retag.box_to_raw_mut.SimplifyCfg-pre-optimizations.after.panic-unwind.mir
@@ -0,0 +1,17 @@
+// MIR for `box_to_raw_mut` after SimplifyCfg-pre-optimizations
+
+fn box_to_raw_mut(_1: &mut Box<i32>) -> *mut i32 {
+    debug x => _1;
+    let mut _0: *mut i32;
+    let mut _2: std::boxed::Box<i32>;
+    let mut _3: *const i32;
+
+    bb0: {
+        Retag([fn entry] _1);
+        _2 = deref_copy (*_1);
+        _3 = (((_2.0: std::ptr::Unique<i32>).0: std::ptr::NonNull<i32>).0: *const i32);
+        _0 = &raw mut (*_3);
+        Retag([raw] _0);
+        return;
+    }
+}
diff --git a/tests/mir-opt/retag.rs b/tests/mir-opt/retag.rs
index 9cee96e429498..17b3c10abeb18 100644
--- a/tests/mir-opt/retag.rs
+++ b/tests/mir-opt/retag.rs
@@ -65,3 +65,8 @@ fn array_casts() {
     let p = &x as *const usize;
     assert_eq!(unsafe { *p.add(1) }, 1);
 }
+
+// EMIT_MIR retag.box_to_raw_mut.SimplifyCfg-pre-optimizations.after.mir
+fn box_to_raw_mut(x: &mut Box<i32>) -> *mut i32 {
+    std::ptr::addr_of_mut!(**x)
+}
diff --git a/tests/run-make/lto-linkage-used-attr/Makefile b/tests/run-make/lto-linkage-used-attr/Makefile
index e78b83890ed3b..fed41a00f84b3 100644
--- a/tests/run-make/lto-linkage-used-attr/Makefile
+++ b/tests/run-make/lto-linkage-used-attr/Makefile
@@ -2,7 +2,6 @@ include ../tools.mk
 
 # Verify that the impl_* symbols are preserved. #108030
 # only-x86_64-unknown-linux-gnu
-# min-llvm-version: 17
 
 all:
 	$(RUSTC) -Cdebuginfo=0 -Copt-level=3 lib.rs
diff --git a/tests/ui/codegen/target-cpus.rs b/tests/ui/codegen/target-cpus.rs
index 85a940f9f74a0..2d46e00f8034e 100644
--- a/tests/ui/codegen/target-cpus.rs
+++ b/tests/ui/codegen/target-cpus.rs
@@ -1,4 +1,3 @@
 //@ needs-llvm-components: webassembly
-//@ min-llvm-version: 17
 //@ compile-flags: --print=target-cpus --target=wasm32-unknown-unknown
 //@ check-pass
diff --git a/tests/ui/fmt/nested-awaits-issue-122674.rs b/tests/ui/fmt/nested-awaits-issue-122674.rs
new file mode 100644
index 0000000000000..f250933dadb48
--- /dev/null
+++ b/tests/ui/fmt/nested-awaits-issue-122674.rs
@@ -0,0 +1,22 @@
+// Non-regression test for issue #122674: a change in the format args visitor missed nested awaits.
+
+//@ edition: 2021
+//@ check-pass
+
+pub fn f1() -> impl std::future::Future<Output = Result<(), String>> + Send {
+    async {
+        should_work().await?;
+        Ok(())
+    }
+}
+
+async fn should_work() -> Result<String, String> {
+    let x = 1;
+    Err(format!("test: {}: {}", x, inner().await?))
+}
+
+async fn inner() -> Result<String, String> {
+    Ok("test".to_string())
+}
+
+fn main() {}
diff --git a/tests/ui/macros/paren-or-brace-expected.rs b/tests/ui/macros/paren-or-brace-expected.rs
new file mode 100644
index 0000000000000..1776fa788847d
--- /dev/null
+++ b/tests/ui/macros/paren-or-brace-expected.rs
@@ -0,0 +1,9 @@
+macro_rules! foo {
+    ( $( $i:ident ),* ) => {
+        $[count($i)]
+        //~^ ERROR expected `(` or `{`, found `[`
+        //~| ERROR
+    };
+}
+
+fn main() {}
diff --git a/tests/ui/macros/paren-or-brace-expected.stderr b/tests/ui/macros/paren-or-brace-expected.stderr
new file mode 100644
index 0000000000000..4d1dda9775133
--- /dev/null
+++ b/tests/ui/macros/paren-or-brace-expected.stderr
@@ -0,0 +1,14 @@
+error: expected `(` or `{`, found `[`
+  --> $DIR/paren-or-brace-expected.rs:3:10
+   |
+LL |         $[count($i)]
+   |          ^^^^^^^^^^^
+
+error: expected one of: `*`, `+`, or `?`
+  --> $DIR/paren-or-brace-expected.rs:3:10
+   |
+LL |         $[count($i)]
+   |          ^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+