add optimization fuel checks to some mir passes

compiler/rustc_mir/src/transform/const_prop.rs

@@ -800,7 +800,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             }
         }
 
-        trace!("attepting to replace {:?} with {:?}", rval, value);
+        trace!("attempting to replace {:?} with {:?}", rval, value);
         if let Err(e) = self.ecx.const_validate_operand(
             value,
             vec![],
@@ -890,6 +890,10 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return false;
         }
 
+        if !self.tcx.consider_optimizing(|| format!("ConstantPropagation - OpTy: {:?}", op)) {
+            return false;
+        }
+
         match *op {
             interpret::Operand::Immediate(Immediate::Scalar(ScalarMaybeUninit::Scalar(s))) => {
                 s.is_bits()

compiler/rustc_mir/src/transform/early_otherwise_branch.rs

@@ -46,6 +46,10 @@ impl<'tcx> MirPass<'tcx> for EarlyOtherwiseBranch {
         let should_cleanup = !opts_to_apply.is_empty();
 
         for opt_to_apply in opts_to_apply {
+            if !tcx.consider_optimizing(|| format!("EarlyOtherwiseBranch {:?}", &opt_to_apply)) {
+                break;
+            }
+
             trace!("SUCCESS: found optimization possibility to apply: {:?}", &opt_to_apply);
 
             let statements_before =

compiler/rustc_mir/src/transform/instcombine.rs

@@ -39,13 +39,21 @@ pub struct InstCombineVisitor<'tcx> {
     tcx: TyCtxt<'tcx>,
 }
 
+impl<'tcx> InstCombineVisitor<'tcx> {
+    fn should_combine(&self, rvalue: &Rvalue<'tcx>, location: Location) -> bool {
+        self.tcx.consider_optimizing(|| {
+            format!("InstCombine - Rvalue: {:?} Location: {:?}", rvalue, location)
+        })
+    }
+}
+
 impl<'tcx> MutVisitor<'tcx> for InstCombineVisitor<'tcx> {
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }
 
     fn visit_rvalue(&mut self, rvalue: &mut Rvalue<'tcx>, location: Location) {
-        if self.optimizations.and_stars.remove(&location) {
+        if self.optimizations.and_stars.remove(&location) && self.should_combine(rvalue, location) {
             debug!("replacing `&*`: {:?}", rvalue);
             let new_place = match rvalue {
                 Rvalue::Ref(_, _, place) => {
@@ -67,18 +75,24 @@ impl<'tcx> MutVisitor<'tcx> for InstCombineVisitor<'tcx> {
         }
 
         if let Some(constant) = self.optimizations.arrays_lengths.remove(&location) {
-            debug!("replacing `Len([_; N])`: {:?}", rvalue);
-            *rvalue = Rvalue::Use(Operand::Constant(box constant));
+            if self.should_combine(rvalue, location) {
+                debug!("replacing `Len([_; N])`: {:?}", rvalue);
+                *rvalue = Rvalue::Use(Operand::Constant(box constant));
+            }
         }
 
         if let Some(operand) = self.optimizations.unneeded_equality_comparison.remove(&location) {
-            debug!("replacing {:?} with {:?}", rvalue, operand);
-            *rvalue = Rvalue::Use(operand);
+            if self.should_combine(rvalue, location) {
+                debug!("replacing {:?} with {:?}", rvalue, operand);
+                *rvalue = Rvalue::Use(operand);
+            }
         }
 
         if let Some(place) = self.optimizations.unneeded_deref.remove(&location) {
-            debug!("unneeded_deref: replacing {:?} with {:?}", rvalue, place);
-            *rvalue = Rvalue::Use(Operand::Copy(place));
+            if self.should_combine(rvalue, location) {
+                debug!("unneeded_deref: replacing {:?} with {:?}", rvalue, place);
+                *rvalue = Rvalue::Use(Operand::Copy(place));
+            }
         }
 
         self.super_rvalue(rvalue, location)

compiler/rustc_mir/src/transform/match_branches.rs

@@ -43,8 +43,13 @@ impl<'tcx> MirPass<'tcx> for MatchBranchSimplification {
         }
 
         let param_env = tcx.param_env(body.source.def_id());
+        let def_id = body.source.def_id();
         let (bbs, local_decls) = body.basic_blocks_and_local_decls_mut();
         'outer: for bb_idx in bbs.indices() {
+            if !tcx.consider_optimizing(|| format!("MatchBranchSimplification {:?} ", def_id)) {
+                continue;
+            }
+
             let (discr, val, switch_ty, first, second) = match bbs[bb_idx].terminator().kind {
                 TerminatorKind::SwitchInt {
                     discr: ref discr @ (Operand::Copy(_) | Operand::Move(_)),

compiler/rustc_mir/src/transform/multiple_return_terminators.rs

@@ -14,6 +14,12 @@ impl<'tcx> MirPass<'tcx> for MultipleReturnTerminators {
             return;
         }
 
+        if !tcx.consider_optimizing(|| {
+            format!("MultipleReturnTerminators {:?} ", body.source.def_id())
+        }) {
+            return;
+        }
+
         // find basic blocks with no statement and a return terminator
         let mut bbs_simple_returns = BitSet::new_empty(body.basic_blocks().len());
         let bbs = body.basic_blocks_mut();

compiler/rustc_mir/src/transform/nrvo.rs

@@ -38,18 +38,22 @@ impl<'tcx> MirPass<'tcx> for RenameReturnPlace {
             return;
         }
 
+        let def_id = body.source.def_id();
         let returned_local = match local_eligible_for_nrvo(body) {
             Some(l) => l,
             None => {
-                debug!("`{:?}` was ineligible for NRVO", body.source.def_id());
+                debug!("`{:?}` was ineligible for NRVO", def_id);
                 return;
             }
         };
 
+        if !tcx.consider_optimizing(|| format!("RenameReturnPlace {:?}", def_id)) {
+            return;
+        }
+
         debug!(
             "`{:?}` was eligible for NRVO, making {:?} the return place",
-            body.source.def_id(),
-            returned_local
+            def_id, returned_local
         );
 
         RenameToReturnPlace { tcx, to_rename: returned_local }.visit_body(body);

compiler/rustc_mir/src/transform/promote_consts.rs

@@ -60,6 +60,10 @@ impl<'tcx> MirPass<'tcx> for PromoteTemps<'tcx> {
             return;
         }
 
+        if !tcx.consider_optimizing(|| format!("PromoteTemps {:?} ", body.source.def_id())) {
+            return;
+        }
+
         let mut rpo = traversal::reverse_postorder(body);
         let ccx = ConstCx::new(tcx, body);
         let (temps, all_candidates) = collect_temps_and_candidates(&ccx, &mut rpo);

compiler/rustc_mir/src/transform/remove_unneeded_drops.rs

@@ -11,6 +11,10 @@ pub struct RemoveUnneededDrops;
 
 impl<'tcx> MirPass<'tcx> for RemoveUnneededDrops {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+        if !tcx.consider_optimizing(|| format!("RemoveUnneededDrops {:?} ", body.source.def_id())) {
+            return;
+        }
+
         trace!("Running RemoveUnneededDrops on {:?}", body.source);
         let mut opt_finder = RemoveUnneededDropsOptimizationFinder {
             tcx,

compiler/rustc_mir/src/transform/unreachable_prop.rs

@@ -18,6 +18,12 @@ impl MirPass<'_> for UnreachablePropagation {
             return;
         }
 
+        if !tcx
+            .consider_optimizing(|| format!("UnreachablePropagation {:?} ", body.source.def_id()))
+        {
+            return;
+        }
+
         let mut unreachable_blocks = FxHashSet::default();
         let mut replacements = FxHashMap::default();
 

src/test/ui/print-fuel/print-fuel.rs

@@ -2,8 +2,8 @@
 #![allow(dead_code)]
 
 // (#55495: The --error-format is to sidestep an issue in our test harness)
-// compile-flags: --error-format human -Z print-fuel=foo
-// build-pass (FIXME(62277): could be check-pass?)
+// 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);

src/test/ui/print-fuel/print-fuel.stderr

@@ -1 +1 @@
-Fuel used by foo: 3
+Fuel used by foo: 4