diff options
| -rw-r--r-- | compiler/rustc_mir_transform/src/const_prop_lint.rs | 41 |
1 files changed, 15 insertions, 26 deletions
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs index db25e22663d..0f1ed1aa9e7 100644 --- a/compiler/rustc_mir_transform/src/const_prop_lint.rs +++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs @@ -101,19 +101,19 @@ impl<'tcx> From<ImmTy<'tcx>> for Value<'tcx> { } impl<'tcx> Value<'tcx> { - fn project( - &self, - proj: impl Iterator<Item = Option<ProjectionElem<FieldIdx, Ty<'tcx>>>>, - ) -> Option<&Value<'tcx>> { + fn project(&self, proj: impl Iterator<Item = Option<PlaceElem<'tcx>>>) -> Option<&Value<'tcx>> { let mut this = self; for proj in proj { this = match (proj?, this) { (ProjectionElem::Field(idx, _), Value::Aggregate { fields, .. }) => { fields.get(idx).unwrap_or(&Value::Uninit) } - (ProjectionElem::Index(idx), Value::Aggregate { fields, .. }) => { - fields.get(idx).unwrap_or(&Value::Uninit) - } + ( + ProjectionElem::ConstantIndex { offset, min_length: 1, from_end: false }, + Value::Aggregate { fields, .. }, + ) => fields + .get(FieldIdx::from_u32(offset.try_into().ok()?)) + .unwrap_or(&Value::Uninit), _ => return None, }; } @@ -205,7 +205,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { fn get_const(&self, place: Place<'tcx>) -> Option<&Value<'tcx>> { self.locals[place.local] - .project(place.projection.iter().map(|proj| self.simple_projection(proj))) + .project(place.projection.iter().map(|proj| self.try_eval_index_offset(proj))) } /// Remove `local` from the pool of `Locals`. Allows writing to them, @@ -719,29 +719,18 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { Some(()) } - fn simple_projection( - &self, - proj: ProjectionElem<Local, Ty<'tcx>>, - ) -> Option<ProjectionElem<FieldIdx, Ty<'tcx>>> { + fn try_eval_index_offset(&self, proj: PlaceElem<'tcx>) -> Option<PlaceElem<'tcx>> { Some(match proj { - ProjectionElem::Deref => ProjectionElem::Deref, - ProjectionElem::Field(idx, ty) => ProjectionElem::Field(idx, ty), ProjectionElem::Index(local) => { let val = self.get_const(local.into())?; let op = val.immediate()?; - ProjectionElem::Index(FieldIdx::from_u32( - self.ecx.read_target_usize(op).ok()?.try_into().ok()?, - )) - } - ProjectionElem::ConstantIndex { offset, min_length, from_end } => { - ProjectionElem::ConstantIndex { offset, min_length, from_end } - } - ProjectionElem::Subslice { from, to, from_end } => { - ProjectionElem::Subslice { from, to, from_end } + ProjectionElem::ConstantIndex { + offset: self.ecx.read_target_usize(op).ok()?, + min_length: 1, + from_end: false, + } } - ProjectionElem::Downcast(a, b) => ProjectionElem::Downcast(a, b), - ProjectionElem::OpaqueCast(ty) => ProjectionElem::OpaqueCast(ty), - ProjectionElem::Subtype(ty) => ProjectionElem::Subtype(ty), + other => other, }) } } |