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Optimize const_prop mir-opt by writing the layouts to ext #96213

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Optimize const_prop mir-opt by writing the layouts to ext #96213

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24 changes: 16 additions & 8 deletions compiler/rustc_mir_transform/src/const_prop.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -362,10 +362,8 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
let param_env = tcx.param_env_reveal_all_normalized(def_id);

let span = tcx.def_span(def_id);
// FIXME: `CanConstProp::check` computes the layout of all locals, return those layouts
// so we can write them to `ecx.frame_mut().locals.layout, reducing the duplication in
// `layout_of` query invocations.
let can_const_prop = CanConstProp::check(tcx, param_env, body);

let (can_const_prop, local_layouts) = CanConstProp::check(tcx, param_env, body);
let mut only_propagate_inside_block_locals = BitSet::new_empty(can_const_prop.len());
for (l, mode) in can_const_prop.iter_enumerated() {
if *mode == ConstPropMode::OnlyInsideOwnBlock {
Expand Down Expand Up @@ -401,6 +399,14 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
)
.expect("failed to push initial stack frame");

// write layouts of locals to ecx, which can reduce the duplication on
// `layout_of` query invocations.
local_layouts.into_iter().zip(ecx.frame().locals.iter()).for_each(|(layout, state)| {
if layout.is_some() {
state.layout.set(layout)
}
});

ConstPropagator {
ecx,
tcx,
Expand Down Expand Up @@ -837,12 +843,11 @@ struct CanConstProp {
}

impl CanConstProp {
/// Returns true if `local` can be propagated
fn check<'tcx>(
tcx: TyCtxt<'tcx>,
param_env: ParamEnv<'tcx>,
body: &Body<'tcx>,
) -> IndexVec<Local, ConstPropMode> {
) -> (IndexVec<Local, ConstPropMode>, IndexVec<Local, Option<TyAndLayout<'tcx>>>) {
let mut cpv = CanConstProp {
can_const_prop: IndexVec::from_elem(ConstPropMode::FullConstProp, &body.local_decls),
found_assignment: BitSet::new_empty(body.local_decls.len()),
Expand All @@ -851,10 +856,13 @@ impl CanConstProp {
body.local_decls.len(),
),
};
let mut local_layouts = IndexVec::from_elem(None, &body.local_decls);
for (local, val) in cpv.can_const_prop.iter_enumerated_mut() {
let ty = body.local_decls[local].ty;
match tcx.layout_of(param_env.and(ty)) {
Ok(layout) if layout.size < Size::from_bytes(MAX_ALLOC_LIMIT) => {}
Ok(layout) if layout.size < Size::from_bytes(MAX_ALLOC_LIMIT) => {
local_layouts[local] = Some(layout);
}
// Either the layout fails to compute, then we can't use this local anyway
// or the local is too large, then we don't want to.
_ => {
Expand Down Expand Up @@ -882,7 +890,7 @@ impl CanConstProp {
}
}
cpv.visit_body(&body);
cpv.can_const_prop
(cpv.can_const_prop, local_layouts)
}
}

Expand Down
24 changes: 16 additions & 8 deletions compiler/rustc_mir_transform/src/const_prop_lint.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -358,10 +358,8 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
let param_env = tcx.param_env_reveal_all_normalized(def_id);

let span = tcx.def_span(def_id);
// FIXME: `CanConstProp::check` computes the layout of all locals, return those layouts
// so we can write them to `ecx.frame_mut().locals.layout, reducing the duplication in
// `layout_of` query invocations.
let can_const_prop = CanConstProp::check(tcx, param_env, body);

let (can_const_prop, local_layouts) = CanConstProp::check(tcx, param_env, body);
let mut only_propagate_inside_block_locals = BitSet::new_empty(can_const_prop.len());
for (l, mode) in can_const_prop.iter_enumerated() {
if *mode == ConstPropMode::OnlyInsideOwnBlock {
Expand Down Expand Up @@ -397,6 +395,14 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
)
.expect("failed to push initial stack frame");

// write layouts of locals to ecx, which can reduce the duplication on
// `layout_of` query invocations.
local_layouts.into_iter().zip(ecx.frame().locals.iter()).for_each(|(layout, state)| {
if layout.is_some() {
state.layout.set(layout)
}
});

ConstPropagator {
ecx,
tcx,
Expand Down Expand Up @@ -718,12 +724,11 @@ struct CanConstProp {
}

impl CanConstProp {
/// Returns true if `local` can be propagated
fn check<'tcx>(
tcx: TyCtxt<'tcx>,
param_env: ParamEnv<'tcx>,
body: &Body<'tcx>,
) -> IndexVec<Local, ConstPropMode> {
) -> (IndexVec<Local, ConstPropMode>, IndexVec<Local, Option<TyAndLayout<'tcx>>>) {
let mut cpv = CanConstProp {
can_const_prop: IndexVec::from_elem(ConstPropMode::FullConstProp, &body.local_decls),
found_assignment: BitSet::new_empty(body.local_decls.len()),
Expand All @@ -732,10 +737,13 @@ impl CanConstProp {
body.local_decls.len(),
),
};
let mut local_layouts = IndexVec::from_elem(None, &body.local_decls);
for (local, val) in cpv.can_const_prop.iter_enumerated_mut() {
let ty = body.local_decls[local].ty;
match tcx.layout_of(param_env.and(ty)) {
Ok(layout) if layout.size < Size::from_bytes(MAX_ALLOC_LIMIT) => {}
Ok(layout) if layout.size < Size::from_bytes(MAX_ALLOC_LIMIT) => {
local_layouts[local] = Some(layout);
}
// Either the layout fails to compute, then we can't use this local anyway
// or the local is too large, then we don't want to.
_ => {
Expand Down Expand Up @@ -763,7 +771,7 @@ impl CanConstProp {
}
}
cpv.visit_body(&body);
cpv.can_const_prop
(cpv.can_const_prop, local_layouts)
}
}

Expand Down