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refactor(mir-transform): Calculate optimization status inside run_passes_inner #160057

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Merged
rust-bors merged 1 commit into from
Jul 28, 2026
Merged

refactor(mir-transform): Calculate optimization status inside run_passes_inner #160057

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2 changes: 1 addition & 1 deletion compiler/rustc_mir_transform/src/coverage/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,7 @@ impl<'tcx> crate::MirPass<'tcx> for InstrumentCoverage {
}

fn is_required(&self) -> bool {
false
true
}
}

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31 changes: 3 additions & 28 deletions compiler/rustc_mir_transform/src/lib.rs
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Expand Up @@ -422,7 +422,6 @@ fn mir_built(tcx: TyCtxt<'_>, def: LocalDefId) -> &Steal<Body<'_>> {
&Lint(sanity_check::SanityCheck),
],
None,
pm::Optimizations::Allowed,
);
tcx.alloc_steal_mir(body)
}
Expand Down Expand Up @@ -479,7 +478,6 @@ fn mir_promoted(
&mut body,
&[&promote_pass, &simplify::SimplifyCfg::PromoteConsts, &coverage::InstrumentCoverage],

@RalfJung RalfJung Jul 28, 2026

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Another SimplifyCfg that's newly controlled by the attribute.

Some(MirPhase::Analysis(AnalysisPhase::Initial)),
pm::Optimizations::Allowed,
);

lint_tail_expr_drop_order::run_lint(tcx, def, &body);
Expand Down Expand Up @@ -526,7 +524,7 @@ fn inner_mir_for_ctfe(tcx: TyCtxt<'_>, def: LocalDefId) -> Body<'_> {
} else {
&[&ctfe_limit::CtfeLimit]
};
pm::run_passes(tcx, &mut body, passes, None, pm::Optimizations::Allowed);
pm::run_passes(tcx, &mut body, passes, None);

body
}
Expand Down Expand Up @@ -613,7 +611,6 @@ pub fn run_analysis_to_runtime_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'
&Lint(post_drop_elaboration::CheckLiveDrops),
],
None,
pm::Optimizations::Allowed,
);
}

Expand All @@ -638,13 +635,7 @@ fn run_analysis_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
&deref_separator::Derefer,
];

pm::run_passes(
tcx,
body,
passes,
Some(MirPhase::Analysis(AnalysisPhase::PostCleanup)),
pm::Optimizations::Allowed,
);
pm::run_passes(tcx, body, passes, Some(MirPhase::Analysis(AnalysisPhase::PostCleanup)));
}

/// Returns the sequence of passes that lowers analysis to runtime MIR.
Expand Down Expand Up @@ -682,13 +673,7 @@ fn run_runtime_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
&simplify::SimplifyCfg::PreOptimizations,

@RalfJung RalfJung Jul 28, 2026

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and another one

];

pm::run_passes(
tcx,
body,
passes,
Some(MirPhase::Runtime(RuntimePhase::PostCleanup)),
pm::Optimizations::Allowed,
);
pm::run_passes(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::PostCleanup)));

// Clear this by anticipation. Optimizations and runtime MIR have no reason to look
// into this information, which is meant for borrowck diagnostics.
Expand All @@ -702,15 +687,6 @@ pub(crate) fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'
WithMinOptLevel(1, x)
}

let def_id = body.source.def_id();
let optimizations = if tcx.def_kind(def_id).has_codegen_attrs()
&& tcx.codegen_fn_attrs(def_id).optimize.do_not_optimize()
{
pm::Optimizations::Suppressed
} else {
pm::Optimizations::Allowed
};

// The main optimizations that we do on MIR.
pm::run_passes(
tcx,
Expand Down Expand Up @@ -793,7 +769,6 @@ pub(crate) fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'
&prettify::ReorderLocals,
],
Some(MirPhase::Runtime(RuntimePhase::Optimized)),
optimizations,
);
}

Expand Down
17 changes: 13 additions & 4 deletions compiler/rustc_mir_transform/src/pass_manager.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -185,7 +185,9 @@ where
/// [required]: MirPass::is_required
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub(crate) enum Optimizations {
/// The current function has `#[optimize(none)]`.
Suppressed,
/// Normal optimizations may run.
Allowed,
}

Expand All @@ -197,7 +199,7 @@ pub(super) fn run_passes_no_validate<'tcx>(
passes: &[&dyn MirPass<'tcx>],
phase_change: Option<MirPhase>,
) {
run_passes_inner(tcx, body, passes, phase_change, false, Optimizations::Allowed);
run_passes_inner(tcx, body, passes, phase_change, false);
}

/// The optional `phase_change` is applied after executing all the passes, if present
Expand All @@ -206,9 +208,8 @@ pub(super) fn run_passes<'tcx>(
body: &mut Body<'tcx>,
passes: &[&dyn MirPass<'tcx>],
phase_change: Option<MirPhase>,
optimizations: Optimizations,
) {
run_passes_inner(tcx, body, passes, phase_change, true, optimizations);
run_passes_inner(tcx, body, passes, phase_change, true);
}

pub(super) fn should_run_pass<'tcx, P>(
Expand Down Expand Up @@ -245,7 +246,6 @@ fn run_passes_inner<'tcx>(
passes: &[&dyn MirPass<'tcx>],
phase_change: Option<MirPhase>,
validate_each: bool,
optimizations: Optimizations,
) {
let overridden_passes = &tcx.sess.opts.unstable_opts.mir_enable_passes;
trace!(?overridden_passes);
Expand Down Expand Up @@ -287,6 +287,15 @@ fn run_passes_inner<'tcx>(
let validate = validate_each & tcx.sess.opts.unstable_opts.validate_mir;
let lint = tcx.sess.opts.unstable_opts.lint_mir;

let def_id = body.source.def_id();
let optimizations = if tcx.def_kind(def_id).has_codegen_attrs()
&& tcx.codegen_fn_attrs(def_id).optimize.do_not_optimize()
{
Optimizations::Suppressed
} else {
Optimizations::Allowed
};

for pass in passes {
let pass_name = pass.name();

Expand Down
2 changes: 0 additions & 2 deletions compiler/rustc_mir_transform/src/shim.rs
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Expand Up @@ -119,7 +119,6 @@ fn make_shim<'tcx>(tcx: TyCtxt<'tcx>, shim: ty::ShimKind<'tcx>) -> Body<'tcx> {
&add_call_guards::CriticalCallEdges,
],
Some(MirPhase::Runtime(RuntimePhase::Optimized)),
pm::Optimizations::Allowed,
);

return body;
Expand All @@ -143,7 +142,6 @@ fn make_shim<'tcx>(tcx: TyCtxt<'tcx>, shim: ty::ShimKind<'tcx>) -> Body<'tcx> {
&add_call_guards::CriticalCallEdges,
],
Some(MirPhase::Runtime(RuntimePhase::PostCleanup)),
pm::Optimizations::Allowed,
);
run_optimization_passes(tcx, &mut body);
debug!("make_shim({:?}) = {:?}", shim, body);
Expand Down
1 change: 0 additions & 1 deletion compiler/rustc_mir_transform/src/shim/async_destructor_ctor.rs
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Expand Up @@ -37,7 +37,6 @@ pub(super) fn build_async_destructor_ctor_shim<'tcx>(
&add_call_guards::CriticalCallEdges,
],
None,
pm::Optimizations::Allowed,

@RalfJung RalfJung Jul 28, 2026

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This is a behavior change I think? Previously SimplifyCfg::MakeShim was always run, now it is controlled by #[optimize].

);
body
}
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6 changes: 3 additions & 3 deletions tests/mir-opt/optimize_none.rs
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Expand Up @@ -16,12 +16,12 @@ pub fn add_noopt() -> i32 {
pub fn const_branch() -> i32 {
// CHECK-LABEL: fn const_branch(
// CHECK: [[BOOL:_[0-9]+]] = const true;
// CHECK: switchInt(move [[BOOL]]) -> [0: [[BB_FALSE:bb[0-9]+]], otherwise: [[BB_TRUE:bb[0-9]+]]];
// CHECK: switchInt(move [[BOOL]]) -> [0: [[BB_FALSE_SHIM:bb[0-9]+]], otherwise: [[BB_TRUE:bb[0-9]+]]];
// CHECK-NEXT: }
// CHECK: [[BB_FALSE_SHIM]]: {
// CHECK-NEXT: goto -> [[BB_FALSE:bb[0-9]+]]
// CHECK: [[BB_FALSE]]: {
// CHECK-NEXT: _0 = const 0
// CHECK-NEXT: goto
// CHECK-NEXT: }
// CHECK: [[BB_TRUE]]: {
// CHECK-NEXT: _0 = const 1
// CHECK-NEXT: goto
Expand Down
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