bjoernager/rust
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Extract process_constant.

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This commit is contained in:
Camille GILLOT 2023-12-31 02:00:30 +00:00
parent be9668d398
commit b22742e8f3
1 changed files with 44 additions and 34 deletions
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78
compiler/rustc_mir_transform/src/jump_threading.rs
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@ -356,6 +356,49 @@ impl<'tcx, 'a> TOFinder<'tcx, 'a> {
None
}
/// If we expect `lhs ?= A`, we have an opportunity if we assume `constant == A`.
#[instrument(level = "trace", skip(self))]
fn process_constant(
&mut self,
bb: BasicBlock,
lhs: PlaceIndex,
constant: OpTy<'tcx>,
state: &mut State<ConditionSet<'a>>,
) {
self.map.for_each_projection_value(
lhs,
constant,
&mut |elem, op| match elem {
TrackElem::Field(idx) => self.ecx.project_field(op, idx.as_usize()).ok(),
TrackElem::Variant(idx) => self.ecx.project_downcast(op, idx).ok(),
TrackElem::Discriminant => {
let variant = self.ecx.read_discriminant(op).ok()?;
let discr_value =
self.ecx.discriminant_for_variant(op.layout.ty, variant).ok()?;
Some(discr_value.into())
}
TrackElem::DerefLen => {
let op: OpTy<'_> = self.ecx.deref_pointer(op).ok()?.into();
let len_usize = op.len(&self.ecx).ok()?;
let layout = self.ecx.layout_of(self.tcx.types.usize).unwrap();
Some(ImmTy::from_uint(len_usize, layout).into())
}
},
&mut |place, op| {
if let Some(conditions) = state.try_get_idx(place, self.map)
&& let Ok(imm) = self.ecx.read_immediate_raw(op)
&& let Some(imm) = imm.right()
&& let Immediate::Scalar(Scalar::Int(int)) = *imm
{
conditions.iter_matches(int).for_each(|c: Condition| {
self.opportunities
.push(ThreadingOpportunity { chain: vec![bb], target: c.target })
})
}
},
);
}
#[instrument(level = "trace", skip(self))]
fn process_operand(
&mut self,
@ -368,40 +411,7 @@ 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_, None, None).ok()?;
self.map.for_each_projection_value(
lhs,
constant,
&mut |elem, op| match elem {
TrackElem::Field(idx) => self.ecx.project_field(op, idx.as_usize()).ok(),
TrackElem::Variant(idx) => self.ecx.project_downcast(op, idx).ok(),
TrackElem::Discriminant => {
let variant = self.ecx.read_discriminant(op).ok()?;
let discr_value =
self.ecx.discriminant_for_variant(op.layout.ty, variant).ok()?;
Some(discr_value.into())
}
TrackElem::DerefLen => {
let op: OpTy<'_> = self.ecx.deref_pointer(op).ok()?.into();
let len_usize = op.len(&self.ecx).ok()?;
let layout = self.ecx.layout_of(self.tcx.types.usize).unwrap();
Some(ImmTy::from_uint(len_usize, layout).into())
}
},
&mut |place, op| {
if let Some(conditions) = state.try_get_idx(place, self.map)
&& let Ok(imm) = self.ecx.read_immediate_raw(op)
&& let Some(imm) = imm.right()
&& let Immediate::Scalar(Scalar::Int(int)) = *imm
{
conditions.iter_matches(int).for_each(|c: Condition| {
self.opportunities.push(ThreadingOpportunity {
chain: vec![bb],
target: c.target,
})
})
}
},
);
self.process_constant(bb, lhs, constant, state);
}
// Transfer the conditions on the copied rhs.
Operand::Move(rhs) | Operand::Copy(rhs) => {