Rollup merge of #115293 - cjgillot:no-fuel, r=wesleywiser,DianQK

Remove -Zfuel.

I'm not sure this feature is used. I only found 2 references in a google search, both referring to its introduction.

Meanwhile, it's a global mutable state, untracked by incremental compilation, so incompatible with it.

28 files changed, 19 insertions, 293 deletions

diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs
index c270ce16726..256266d2965 100644
--- a/compiler/rustc_driver_impl/src/lib.rs
+++ b/compiler/rustc_driver_impl/src/lib.rs
@@ -472,10 +472,6 @@ fn run_compiler(
             linker.link(sess, codegen_backend)?
         }
 
-        if let Some(fuel) = sess.opts.unstable_opts.print_fuel.as_deref() {
-            eprintln!("Fuel used by {}: {}", fuel, sess.print_fuel.load(Ordering::SeqCst));
-        }
-
         Ok(())
     })
 }
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index e48c4d46b59..6beae14100d 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -784,7 +784,6 @@ fn test_unstable_options_tracking_hash() {
     tracked!(flatten_format_args, false);
     tracked!(fmt_debug, FmtDebug::Shallow);
     tracked!(force_unstable_if_unmarked, true);
-    tracked!(fuel, Some(("abc".to_string(), 99)));
     tracked!(function_return, FunctionReturn::ThunkExtern);
     tracked!(function_sections, Some(false));
     tracked!(human_readable_cgu_names, true);
@@ -830,7 +829,6 @@ fn test_unstable_options_tracking_hash() {
     tracked!(plt, Some(true));
     tracked!(polonius, Polonius::Legacy);
     tracked!(precise_enum_drop_elaboration, false);
-    tracked!(print_fuel, Some("abc".to_string()));
     tracked!(profile_sample_use, Some(PathBuf::from("abc")));
     tracked!(profiler_runtime, "abc".to_string());
     tracked!(regparm, Some(3));
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index d982122e2aa..5bf62a17c8e 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -1566,10 +1566,6 @@ impl<'tcx> TyCtxt<'tcx> {
         }
     }
 
-    pub fn consider_optimizing<T: Fn() -> String>(self, msg: T) -> bool {
-        self.sess.consider_optimizing(|| self.crate_name(LOCAL_CRATE), msg)
-    }
-
     /// Obtain all lang items of this crate and all dependencies (recursively)
     pub fn lang_items(self) -> &'tcx rustc_hir::lang_items::LanguageItems {
         self.get_lang_items(())
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 2b532701904..c7a2223ecd7 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -1558,10 +1558,7 @@ impl<'tcx> TyCtxt<'tcx> {
         let is_box = self.is_lang_item(did.to_def_id(), LangItem::OwnedBox);
 
         // This is here instead of layout because the choice must make it into metadata.
-        if is_box
-            || !self
-                .consider_optimizing(|| format!("Reorder fields of {:?}", self.def_path_str(did)))
-        {
+        if is_box {
             flags.insert(ReprFlags::IS_LINEAR);
         }
 
diff --git a/compiler/rustc_mir_transform/src/dest_prop.rs b/compiler/rustc_mir_transform/src/dest_prop.rs
index 9c74b2f0839..8f977d2979e 100644
--- a/compiler/rustc_mir_transform/src/dest_prop.rs
+++ b/compiler/rustc_mir_transform/src/dest_prop.rs
@@ -217,11 +217,6 @@ impl<'tcx> crate::MirPass<'tcx> for DestinationPropagation {
                 else {
                     continue;
                 };
-                if !tcx.consider_optimizing(|| {
-                    format!("{} round {}", tcx.def_path_str(def_id), round_count)
-                }) {
-                    break;
-                }
 
                 // Replace `src` by `dest` everywhere.
                 merges.insert(*src, *dest);
diff --git a/compiler/rustc_mir_transform/src/early_otherwise_branch.rs b/compiler/rustc_mir_transform/src/early_otherwise_branch.rs
index 704ed508b22..17c8348140a 100644
--- a/compiler/rustc_mir_transform/src/early_otherwise_branch.rs
+++ b/compiler/rustc_mir_transform/src/early_otherwise_branch.rs
@@ -108,10 +108,6 @@ impl<'tcx> crate::MirPass<'tcx> for EarlyOtherwiseBranch {
             let parent = BasicBlock::from_usize(i);
             let Some(opt_data) = evaluate_candidate(tcx, body, parent) else { continue };
 
-            if !tcx.consider_optimizing(|| format!("EarlyOtherwiseBranch {opt_data:?}")) {
-                break;
-            }
-
             trace!("SUCCESS: found optimization possibility to apply: {opt_data:?}");
 
             should_cleanup = true;
diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index 00f6c3845d4..0878fa26a92 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -210,12 +210,6 @@ impl<'tcx> Inliner<'tcx> {
         let callee_body = try_instance_mir(self.tcx, callsite.callee.def)?;
         self.check_mir_body(callsite, callee_body, callee_attrs, cross_crate_inlinable)?;
 
-        if !self.tcx.consider_optimizing(|| {
-            format!("Inline {:?} into {:?}", callsite.callee, caller_body.source)
-        }) {
-            return Err("optimization fuel exhausted");
-        }
-
         let Ok(callee_body) = callsite.callee.try_instantiate_mir_and_normalize_erasing_regions(
             self.tcx,
             self.typing_env,
diff --git a/compiler/rustc_mir_transform/src/instsimplify.rs b/compiler/rustc_mir_transform/src/instsimplify.rs
index 3352d583f2c..a6ba2f32d32 100644
--- a/compiler/rustc_mir_transform/src/instsimplify.rs
+++ b/compiler/rustc_mir_transform/src/instsimplify.rs
@@ -7,8 +7,8 @@ use rustc_middle::bug;
 use rustc_middle::mir::*;
 use rustc_middle::ty::layout::ValidityRequirement;
 use rustc_middle::ty::{self, GenericArgsRef, Ty, TyCtxt, layout};
-use rustc_span::sym;
 use rustc_span::symbol::Symbol;
+use rustc_span::{DUMMY_SP, sym};
 
 use crate::simplify::simplify_duplicate_switch_targets;
 use crate::take_array;
@@ -43,12 +43,12 @@ impl<'tcx> crate::MirPass<'tcx> for InstSimplify {
                 match statement.kind {
                     StatementKind::Assign(box (_place, ref mut rvalue)) => {
                         if !preserve_ub_checks {
-                            ctx.simplify_ub_check(&statement.source_info, rvalue);
+                            ctx.simplify_ub_check(rvalue);
                         }
-                        ctx.simplify_bool_cmp(&statement.source_info, rvalue);
-                        ctx.simplify_ref_deref(&statement.source_info, rvalue);
-                        ctx.simplify_len(&statement.source_info, rvalue);
-                        ctx.simplify_ptr_aggregate(&statement.source_info, rvalue);
+                        ctx.simplify_bool_cmp(rvalue);
+                        ctx.simplify_ref_deref(rvalue);
+                        ctx.simplify_len(rvalue);
+                        ctx.simplify_ptr_aggregate(rvalue);
                         ctx.simplify_cast(rvalue);
                     }
                     _ => {}
@@ -70,23 +70,8 @@ struct InstSimplifyContext<'a, 'tcx> {
 }
 
 impl<'tcx> InstSimplifyContext<'_, 'tcx> {
-    fn should_simplify(&self, source_info: &SourceInfo, rvalue: &Rvalue<'tcx>) -> bool {
-        self.should_simplify_custom(source_info, "Rvalue", rvalue)
-    }
-
-    fn should_simplify_custom(
-        &self,
-        source_info: &SourceInfo,
-        label: &str,
-        value: impl std::fmt::Debug,
-    ) -> bool {
-        self.tcx.consider_optimizing(|| {
-            format!("InstSimplify - {label}: {value:?} SourceInfo: {source_info:?}")
-        })
-    }
-
     /// Transform boolean comparisons into logical operations.
-    fn simplify_bool_cmp(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) {
+    fn simplify_bool_cmp(&self, rvalue: &mut Rvalue<'tcx>) {
         match rvalue {
             Rvalue::BinaryOp(op @ (BinOp::Eq | BinOp::Ne), box (a, b)) => {
                 let new = match (op, self.try_eval_bool(a), self.try_eval_bool(b)) {
@@ -117,9 +102,7 @@ impl<'tcx> InstSimplifyContext<'_, 'tcx> {
                     _ => None,
                 };
 
-                if let Some(new) = new
-                    && self.should_simplify(source_info, rvalue)
-                {
+                if let Some(new) = new {
                     *rvalue = new;
                 }
             }
@@ -134,17 +117,13 @@ impl<'tcx> InstSimplifyContext<'_, 'tcx> {
     }
 
     /// Transform `&(*a)` ==> `a`.
-    fn simplify_ref_deref(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) {
+    fn simplify_ref_deref(&self, rvalue: &mut Rvalue<'tcx>) {
         if let Rvalue::Ref(_, _, place) | Rvalue::RawPtr(_, place) = rvalue {
             if let Some((base, ProjectionElem::Deref)) = place.as_ref().last_projection() {
                 if rvalue.ty(self.local_decls, self.tcx) != base.ty(self.local_decls, self.tcx).ty {
                     return;
                 }
 
-                if !self.should_simplify(source_info, rvalue) {
-                    return;
-                }
-
                 *rvalue = Rvalue::Use(Operand::Copy(Place {
                     local: base.local,
                     projection: self.tcx.mk_place_elems(base.projection),
@@ -154,36 +133,24 @@ impl<'tcx> InstSimplifyContext<'_, 'tcx> {
     }
 
     /// Transform `Len([_; N])` ==> `N`.
-    fn simplify_len(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) {
+    fn simplify_len(&self, rvalue: &mut Rvalue<'tcx>) {
         if let Rvalue::Len(ref place) = *rvalue {
             let place_ty = place.ty(self.local_decls, self.tcx).ty;
             if let ty::Array(_, len) = *place_ty.kind() {
-                if !self.should_simplify(source_info, rvalue) {
-                    return;
-                }
-
                 let const_ = Const::from_ty_const(len, self.tcx.types.usize, self.tcx);
-                let constant = ConstOperand { span: source_info.span, const_, user_ty: None };
+                let constant = ConstOperand { span: DUMMY_SP, const_, user_ty: None };
                 *rvalue = Rvalue::Use(Operand::Constant(Box::new(constant)));
             }
         }
     }
 
     /// Transform `Aggregate(RawPtr, [p, ()])` ==> `Cast(PtrToPtr, p)`.
-    fn simplify_ptr_aggregate(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) {
+    fn simplify_ptr_aggregate(&self, rvalue: &mut Rvalue<'tcx>) {
         if let Rvalue::Aggregate(box AggregateKind::RawPtr(pointee_ty, mutability), fields) = rvalue
         {
             let meta_ty = fields.raw[1].ty(self.local_decls, self.tcx);
             if meta_ty.is_unit() {
                 // The mutable borrows we're holding prevent printing `rvalue` here
-                if !self.should_simplify_custom(
-                    source_info,
-                    "Aggregate::RawPtr",
-                    (&pointee_ty, *mutability, &fields),
-                ) {
-                    return;
-                }
-
                 let mut fields = std::mem::take(fields);
                 let _meta = fields.pop().unwrap();
                 let data = fields.pop().unwrap();
@@ -193,10 +160,10 @@ impl<'tcx> InstSimplifyContext<'_, 'tcx> {
         }
     }
 
-    fn simplify_ub_check(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) {
+    fn simplify_ub_check(&self, rvalue: &mut Rvalue<'tcx>) {
         if let Rvalue::NullaryOp(NullOp::UbChecks, _) = *rvalue {
             let const_ = Const::from_bool(self.tcx, self.tcx.sess.ub_checks());
-            let constant = ConstOperand { span: source_info.span, const_, user_ty: None };
+            let constant = ConstOperand { span: DUMMY_SP, const_, user_ty: None };
             *rvalue = Rvalue::Use(Operand::Constant(Box::new(constant)));
         }
     }
@@ -284,16 +251,6 @@ impl<'tcx> InstSimplifyContext<'_, 'tcx> {
             return;
         }
 
-        if !self.tcx.consider_optimizing(|| {
-            format!(
-                "InstSimplify - Call: {:?} SourceInfo: {:?}",
-                (fn_def_id, fn_args),
-                terminator.source_info
-            )
-        }) {
-            return;
-        }
-
         let Ok([arg]) = take_array(args) else { return };
         let Some(arg_place) = arg.node.place() else { return };
 
diff --git a/compiler/rustc_mir_transform/src/match_branches.rs b/compiler/rustc_mir_transform/src/match_branches.rs
index ff027680c49..20e2a65b311 100644
--- a/compiler/rustc_mir_transform/src/match_branches.rs
+++ b/compiler/rustc_mir_transform/src/match_branches.rs
@@ -18,16 +18,11 @@ impl<'tcx> crate::MirPass<'tcx> for MatchBranchSimplification {
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        let def_id = body.source.def_id();
         let typing_env = body.typing_env(tcx);
         let mut should_cleanup = false;
         for i in 0..body.basic_blocks.len() {
             let bbs = &*body.basic_blocks;
             let bb_idx = BasicBlock::from_usize(i);
-            if !tcx.consider_optimizing(|| format!("MatchBranchSimplification {def_id:?} ")) {
-                continue;
-            }
-
             match bbs[bb_idx].terminator().kind {
                 TerminatorKind::SwitchInt {
                     discr: ref _discr @ (Operand::Copy(_) | Operand::Move(_)),
diff --git a/compiler/rustc_mir_transform/src/multiple_return_terminators.rs b/compiler/rustc_mir_transform/src/multiple_return_terminators.rs
index b6d6ef5de1d..a9227524ce5 100644
--- a/compiler/rustc_mir_transform/src/multiple_return_terminators.rs
+++ b/compiler/rustc_mir_transform/src/multiple_return_terminators.rs
@@ -14,10 +14,9 @@ impl<'tcx> crate::MirPass<'tcx> for MultipleReturnTerminators {
         sess.mir_opt_level() >= 4
     }
 
-    fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+    fn run_pass(&self, _: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         // find basic blocks with no statement and a return terminator
         let mut bbs_simple_returns = BitSet::new_empty(body.basic_blocks.len());
-        let def_id = body.source.def_id();
         let bbs = body.basic_blocks_mut();
         for idx in bbs.indices() {
             if bbs[idx].statements.is_empty()
@@ -28,10 +27,6 @@ impl<'tcx> crate::MirPass<'tcx> for MultipleReturnTerminators {
         }
 
         for bb in bbs {
-            if !tcx.consider_optimizing(|| format!("MultipleReturnTerminators {def_id:?} ")) {
-                break;
-            }
-
             if let TerminatorKind::Goto { target } = bb.terminator().kind {
                 if bbs_simple_returns.contains(target) {
                     bb.terminator_mut().kind = TerminatorKind::Return;
diff --git a/compiler/rustc_mir_transform/src/nrvo.rs b/compiler/rustc_mir_transform/src/nrvo.rs
index 98fa149e2bc..cd026ed6806 100644
--- a/compiler/rustc_mir_transform/src/nrvo.rs
+++ b/compiler/rustc_mir_transform/src/nrvo.rs
@@ -45,10 +45,6 @@ impl<'tcx> crate::MirPass<'tcx> for RenameReturnPlace {
             return;
         };
 
-        if !tcx.consider_optimizing(|| format!("RenameReturnPlace {def_id:?}")) {
-            return;
-        }
-
         debug!(
             "`{:?}` was eligible for NRVO, making {:?} the return place",
             def_id, returned_local
diff --git a/compiler/rustc_mir_transform/src/remove_unneeded_drops.rs b/compiler/rustc_mir_transform/src/remove_unneeded_drops.rs
index a535be798cd..e335051d656 100644
--- a/compiler/rustc_mir_transform/src/remove_unneeded_drops.rs
+++ b/compiler/rustc_mir_transform/src/remove_unneeded_drops.rs
@@ -26,11 +26,6 @@ impl<'tcx> crate::MirPass<'tcx> for RemoveUnneededDrops {
                 if ty.ty.needs_drop(tcx, typing_env) {
                     continue;
                 }
-                if !tcx.consider_optimizing(|| {
-                    format!("RemoveUnneededDrops {:?}", body.source.def_id())
-                }) {
-                    continue;
-                }
                 debug!("SUCCESS: replacing `drop` with goto({:?})", target);
                 terminator.kind = TerminatorKind::Goto { target };
                 should_simplify = true;
diff --git a/compiler/rustc_mir_transform/src/remove_zsts.rs b/compiler/rustc_mir_transform/src/remove_zsts.rs
index 6fd70fbe9b0..64e183bcbc0 100644
--- a/compiler/rustc_mir_transform/src/remove_zsts.rs
+++ b/compiler/rustc_mir_transform/src/remove_zsts.rs
@@ -17,10 +17,6 @@ impl<'tcx> crate::MirPass<'tcx> for RemoveZsts {
             return;
         }
 
-        if !tcx.consider_optimizing(|| format!("RemoveZsts - {:?}", body.source.def_id())) {
-            return;
-        }
-
         let typing_env = body.typing_env(tcx);
         let local_decls = &body.local_decls;
         let mut replacer = Replacer { tcx, typing_env, local_decls };
@@ -94,16 +90,12 @@ impl<'tcx> MutVisitor<'tcx> for Replacer<'_, 'tcx> {
         }
     }
 
-    fn visit_operand(&mut self, operand: &mut Operand<'tcx>, loc: Location) {
+    fn visit_operand(&mut self, operand: &mut Operand<'tcx>, _: Location) {
         if let Operand::Constant(_) = operand {
             return;
         }
         let op_ty = operand.ty(self.local_decls, self.tcx);
-        if self.known_to_be_zst(op_ty)
-            && self.tcx.consider_optimizing(|| {
-                format!("RemoveZsts - Operand: {operand:?} Location: {loc:?}")
-            })
-        {
+        if self.known_to_be_zst(op_ty) {
             *operand = Operand::Constant(Box::new(self.make_zst(op_ty)))
         }
     }
diff --git a/compiler/rustc_mir_transform/src/unreachable_prop.rs b/compiler/rustc_mir_transform/src/unreachable_prop.rs
index 9cd32459c7b..734703ec78b 100644
--- a/compiler/rustc_mir_transform/src/unreachable_prop.rs
+++ b/compiler/rustc_mir_transform/src/unreachable_prop.rs
@@ -43,12 +43,6 @@ impl crate::MirPass<'_> for UnreachablePropagation {
             }
         }
 
-        if !tcx
-            .consider_optimizing(|| format!("UnreachablePropagation {:?} ", body.source.def_id()))
-        {
-            return;
-        }
-
         patch.apply(body);
 
         // We do want do keep some unreachable blocks, but make them empty.
diff --git a/compiler/rustc_session/messages.ftl b/compiler/rustc_session/messages.ftl
index 893c532f1fb..8fd87893a98 100644
--- a/compiler/rustc_session/messages.ftl
+++ b/compiler/rustc_session/messages.ftl
@@ -84,8 +84,6 @@ session_not_supported = not supported
 
 session_octal_float_literal_not_supported = octal float literal is not supported
 
-session_optimization_fuel_exhausted = optimization-fuel-exhausted: {$msg}
-
 session_profile_sample_use_file_does_not_exist = file `{$path}` passed to `-C profile-sample-use` does not exist
 
 session_profile_use_file_does_not_exist = file `{$path}` passed to `-C profile-use` does not exist
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index d60c56fee75..0124397ea46 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -2356,14 +2356,6 @@ pub fn build_session_options(early_dcx: &mut EarlyDiagCtxt, matches: &getopts::M
         early_dcx.early_warn(format!("number of threads was capped at {}", parse::MAX_THREADS_CAP));
     }
 
-    let fuel = unstable_opts.fuel.is_some() || unstable_opts.print_fuel.is_some();
-    if fuel && unstable_opts.threads > 1 {
-        early_dcx.early_fatal("optimization fuel is incompatible with multiple threads");
-    }
-    if fuel && cg.incremental.is_some() {
-        early_dcx.early_fatal("optimization fuel is incompatible with incremental compilation");
-    }
-
     let incremental = cg.incremental.as_ref().map(PathBuf::from);
 
     let assert_incr_state = parse_assert_incr_state(early_dcx, &unstable_opts.assert_incr_state);
diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index 33f84f10447..736a5ce0704 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -464,12 +464,6 @@ pub fn report_lit_error(
 }
 
 #[derive(Diagnostic)]
-#[diag(session_optimization_fuel_exhausted)]
-pub(crate) struct OptimisationFuelExhausted {
-    pub(crate) msg: String,
-}
-
-#[derive(Diagnostic)]
 #[diag(session_incompatible_linker_flavor)]
 #[note]
 pub(crate) struct IncompatibleLinkerFlavor {
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index edee7b4468c..a2d75917c82 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -394,7 +394,6 @@ mod desc {
     pub(crate) const parse_collapse_macro_debuginfo: &str = "one of `no`, `external`, or `yes`";
     pub(crate) const parse_strip: &str = "either `none`, `debuginfo`, or `symbols`";
     pub(crate) const parse_linker_flavor: &str = ::rustc_target::spec::LinkerFlavorCli::one_of();
-    pub(crate) const parse_optimization_fuel: &str = "crate=integer";
     pub(crate) const parse_dump_mono_stats: &str = "`markdown` (default) or `json`";
     pub(crate) const parse_instrument_coverage: &str = parse_bool;
     pub(crate) const parse_coverage_options: &str =
@@ -948,21 +947,6 @@ pub mod parse {
         true
     }
 
-    pub(crate) fn parse_optimization_fuel(
-        slot: &mut Option<(String, u64)>,
-        v: Option<&str>,
-    ) -> bool {
-        match v {
-            None => false,
-            Some(s) => {
-                let [crate_name, fuel] = *s.split('=').collect::<Vec<_>>() else { return false };
-                let Ok(fuel) = fuel.parse::<u64>() else { return false };
-                *slot = Some((crate_name.to_string(), fuel));
-                true
-            }
-        }
-    }
-
     pub(crate) fn parse_unpretty(slot: &mut Option<String>, v: Option<&str>) -> bool {
         match v {
             None => false,
@@ -1794,8 +1778,6 @@ options! {
         `shallow` prints only type names, `none` prints nothing and disables `{:?}`. (default: `full`)"),
     force_unstable_if_unmarked: bool = (false, parse_bool, [TRACKED],
         "force all crates to be `rustc_private` unstable (default: no)"),
-    fuel: Option<(String, u64)> = (None, parse_optimization_fuel, [TRACKED],
-        "set the optimization fuel quota for a crate"),
     function_return: FunctionReturn = (FunctionReturn::default(), parse_function_return, [TRACKED],
         "replace returns with jumps to `__x86_return_thunk` (default: `keep`)"),
     function_sections: Option<bool> = (None, parse_opt_bool, [TRACKED],
@@ -1978,8 +1960,6 @@ options! {
     #[rustc_lint_opt_deny_field_access("use `Session::print_codegen_stats` instead of this field")]
     print_codegen_stats: bool = (false, parse_bool, [UNTRACKED],
         "print codegen statistics (default: no)"),
-    print_fuel: Option<String> = (None, parse_opt_string, [TRACKED],
-        "make rustc print the total optimization fuel used by a crate"),
     print_llvm_passes: bool = (false, parse_bool, [UNTRACKED],
         "print the LLVM optimization passes being run (default: no)"),
     print_mono_items: Option<String> = (None, parse_opt_string, [UNTRACKED],
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 29fabdd1deb..f585410adb9 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -4,7 +4,6 @@ use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::sync::Arc;
 use std::sync::atomic::AtomicBool;
-use std::sync::atomic::Ordering::SeqCst;
 use std::{env, fmt, io};
 
 use rustc_data_structures::flock;
@@ -12,7 +11,7 @@ use rustc_data_structures::fx::{FxHashMap, FxIndexSet};
 use rustc_data_structures::jobserver::{self, Client};
 use rustc_data_structures::profiling::{SelfProfiler, SelfProfilerRef};
 use rustc_data_structures::sync::{
-    AtomicU64, DynSend, DynSync, Lock, Lrc, MappedReadGuard, ReadGuard, RwLock,
+    DynSend, DynSync, Lock, Lrc, MappedReadGuard, ReadGuard, RwLock,
 };
 use rustc_errors::annotate_snippet_emitter_writer::AnnotateSnippetEmitter;
 use rustc_errors::codes::*;
@@ -49,13 +48,6 @@ use crate::parse::{ParseSess, add_feature_diagnostics};
 use crate::search_paths::SearchPath;
 use crate::{errors, filesearch, lint};
 
-struct OptimizationFuel {
-    /// If `-zfuel=crate=n` is specified, initially set to `n`, otherwise `0`.
-    remaining: u64,
-    /// We're rejecting all further optimizations.
-    out_of_fuel: bool,
-}
-
 /// The behavior of the CTFE engine when an error occurs with regards to backtraces.
 #[derive(Clone, Copy)]
 pub enum CtfeBacktrace {
@@ -163,12 +155,6 @@ pub struct Session {
     /// Data about code being compiled, gathered during compilation.
     pub code_stats: CodeStats,
 
-    /// Tracks fuel info if `-zfuel=crate=n` is specified.
-    optimization_fuel: Lock<OptimizationFuel>,
-
-    /// Always set to zero and incremented so that we can print fuel expended by a crate.
-    pub print_fuel: AtomicU64,
-
     /// Loaded up early on in the initialization of this `Session` to avoid
     /// false positives about a job server in our environment.
     pub jobserver: Client,
@@ -532,41 +518,6 @@ impl Session {
         self.opts.incremental.as_ref().map(|_| self.incr_comp_session_dir())
     }
 
-    /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n.
-    /// This expends fuel if applicable, and records fuel if applicable.
-    pub fn consider_optimizing(
-        &self,
-        get_crate_name: impl Fn() -> Symbol,
-        msg: impl Fn() -> String,
-    ) -> bool {
-        let mut ret = true;
-        if let Some((ref c, _)) = self.opts.unstable_opts.fuel {
-            if c == get_crate_name().as_str() {
-                assert_eq!(self.threads(), 1);
-                let mut fuel = self.optimization_fuel.lock();
-                ret = fuel.remaining != 0;
-                if fuel.remaining == 0 && !fuel.out_of_fuel {
-                    if self.dcx().can_emit_warnings() {
-                        // We only call `msg` in case we can actually emit warnings.
-                        // Otherwise, this could cause a `must_produce_diag` ICE
-                        // (issue #79546).
-                        self.dcx().emit_warn(errors::OptimisationFuelExhausted { msg: msg() });
-                    }
-                    fuel.out_of_fuel = true;
-                } else if fuel.remaining > 0 {
-                    fuel.remaining -= 1;
-                }
-            }
-        }
-        if let Some(ref c) = self.opts.unstable_opts.print_fuel {
-            if c == get_crate_name().as_str() {
-                assert_eq!(self.threads(), 1);
-                self.print_fuel.fetch_add(1, SeqCst);
-            }
-        }
-        ret
-    }
-
     /// Is this edition 2015?
     pub fn is_rust_2015(&self) -> bool {
         self.edition().is_rust_2015()
@@ -1097,12 +1048,6 @@ pub fn build_session(
         Lrc::new(SearchPath::from_sysroot_and_triple(&sysroot, target_triple))
     };
 
-    let optimization_fuel = Lock::new(OptimizationFuel {
-        remaining: sopts.unstable_opts.fuel.as_ref().map_or(0, |&(_, i)| i),
-        out_of_fuel: false,
-    });
-    let print_fuel = AtomicU64::new(0);
-
     let prof = SelfProfilerRef::new(
         self_profiler,
         sopts.unstable_opts.time_passes.then(|| sopts.unstable_opts.time_passes_format),
@@ -1130,8 +1075,6 @@ pub fn build_session(
         incr_comp_session: RwLock::new(IncrCompSession::NotInitialized),
         prof,
         code_stats: Default::default(),
-        optimization_fuel,
-        print_fuel,
         jobserver: jobserver::client(),
         lint_store: None,
         registered_lints: false,
diff --git a/src/tools/tidy/src/issues.txt b/src/tools/tidy/src/issues.txt
index 932a58788e0..ac82a17e145 100644
--- a/src/tools/tidy/src/issues.txt
+++ b/src/tools/tidy/src/issues.txt
@@ -2756,7 +2756,6 @@ ui/lint/issue-57410-1.rs
 ui/lint/issue-57410.rs
 ui/lint/issue-63364.rs
 ui/lint/issue-70819-dont-override-forbid-in-same-scope.rs
-ui/lint/issue-79546-fuel-ice.rs
 ui/lint/issue-79744.rs
 ui/lint/issue-81218.rs
 ui/lint/issue-83477.rs
diff --git a/tests/ui/fuel/optimization-fuel-0.rs b/tests/ui/fuel/optimization-fuel-0.rs
deleted file mode 100644
index cbcb1d329a3..00000000000
--- a/tests/ui/fuel/optimization-fuel-0.rs
+++ /dev/null
@@ -1,17 +0,0 @@
-//@ run-pass
-
-#![crate_name="foo"]
-
-use std::mem::size_of;
-
-//@ compile-flags: -Z fuel=foo=0
-
-#[allow(dead_code)]
-struct S1(u8, u16, u8);
-#[allow(dead_code)]
-struct S2(u8, u16, u8);
-
-fn main() {
-    assert_eq!(size_of::<S1>(), 6);
-    assert_eq!(size_of::<S2>(), 6);
-}
diff --git a/tests/ui/fuel/optimization-fuel-0.stderr b/tests/ui/fuel/optimization-fuel-0.stderr
deleted file mode 100644
index f0e2ebfc37a..00000000000
--- a/tests/ui/fuel/optimization-fuel-0.stderr
+++ /dev/null
@@ -1,4 +0,0 @@
-warning: optimization-fuel-exhausted: Reorder fields of "S1"
-
-warning: 1 warning emitted
-
diff --git a/tests/ui/fuel/optimization-fuel-1.rs b/tests/ui/fuel/optimization-fuel-1.rs
deleted file mode 100644
index 97edb0bd259..00000000000
--- a/tests/ui/fuel/optimization-fuel-1.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-//@ run-pass
-
-#![crate_name="foo"]
-
-use std::mem::size_of;
-
-//@ compile-flags: -Z fuel=foo=1
-
-#[allow(dead_code)]
-struct S1(u8, u16, u8);
-#[allow(dead_code)]
-struct S2(u8, u16, u8);
-
-fn main() {
-    let optimized = (size_of::<S1>() == 4) as usize
-        +(size_of::<S2>() == 4) as usize;
-    assert_eq!(optimized, 1);
-}
diff --git a/tests/ui/fuel/optimization-fuel-1.stderr b/tests/ui/fuel/optimization-fuel-1.stderr
deleted file mode 100644
index 53eafb05830..00000000000
--- a/tests/ui/fuel/optimization-fuel-1.stderr
+++ /dev/null
@@ -1,4 +0,0 @@
-warning: optimization-fuel-exhausted: Reorder fields of "S2"
-
-warning: 1 warning emitted
-
diff --git a/tests/ui/fuel/print-fuel.rs b/tests/ui/fuel/print-fuel.rs
deleted file mode 100644
index fd7e568bea7..00000000000
--- a/tests/ui/fuel/print-fuel.rs
+++ /dev/null
@@ -1,13 +0,0 @@
-#![crate_name="foo"]
-#![allow(dead_code)]
-
-// (#55495: The --error-format is to sidestep an issue in our test harness)
-//@ compile-flags: -C opt-level=0 --error-format human -Z print-fuel=foo
-//@ check-pass
-
-struct S1(u8, u16, u8);
-struct S2(u8, u16, u8);
-struct S3(u8, u16, u8);
-
-fn main() {
-}
diff --git a/tests/ui/fuel/print-fuel.stderr b/tests/ui/fuel/print-fuel.stderr
deleted file mode 100644
index cc88cc077bb..00000000000
--- a/tests/ui/fuel/print-fuel.stderr
+++ /dev/null
@@ -1 +0,0 @@
-Fuel used by foo: 3
diff --git a/tests/ui/invalid-compile-flags/fuel.rs b/tests/ui/invalid-compile-flags/fuel.rs
deleted file mode 100644
index 855aa858122..00000000000
--- a/tests/ui/invalid-compile-flags/fuel.rs
+++ /dev/null
@@ -1,11 +0,0 @@
-//@ revisions: incremental threads
-//@ dont-check-compiler-stderr
-//
-//@ [threads] compile-flags: -Zfuel=a=1 -Zthreads=2
-//@ [threads] error-pattern:optimization fuel is incompatible with multiple threads
-//
-//@ [incremental] incremental
-//@ [incremental] compile-flags: -Zprint-fuel=a
-//@ [incremental] error-pattern:optimization fuel is incompatible with incremental compilation
-
-fn main() {}
diff --git a/tests/ui/lint/issue-79546-fuel-ice.rs b/tests/ui/lint/issue-79546-fuel-ice.rs
deleted file mode 100644
index dbee924d26e..00000000000
--- a/tests/ui/lint/issue-79546-fuel-ice.rs
+++ /dev/null
@@ -1,8 +0,0 @@
-// Regression test for the ICE described in #79546.
-
-//@ compile-flags: --cap-lints=allow -Zfuel=issue79546=0
-//@ check-pass
-#![crate_name="issue79546"]
-
-struct S;
-fn main() {}