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MIR-build: No longer emit assumes in enum-as casting

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This just uses the `valid_range` from the backend, so it's duplicating the range metadata that now we include on parameters and loads.
This commit is contained in:
Scott McMurray
2025-07-23 22:13:05 -07:00
parent a7a1618e6c
commit 01524abb05
11 changed files with 38 additions and 151 deletions
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80
compiler/rustc_mir_build/src/builder/expr/as_rvalue.rs
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@@ -1,6 +1,6 @@
//! See docs in `build/expr/mod.rs`.
use rustc_abi::{BackendRepr, FieldIdx, Primitive};
use rustc_abi::FieldIdx;
use rustc_hir::lang_items::LangItem;
use rustc_index::{Idx, IndexVec};
use rustc_middle::bug;
@@ -9,7 +9,6 @@ use rustc_middle::mir::interpret::Scalar;
use rustc_middle::mir::*;
use rustc_middle::thir::*;
use rustc_middle::ty::cast::{CastTy, mir_cast_kind};
use rustc_middle::ty::layout::IntegerExt;
use rustc_middle::ty::util::IntTypeExt;
use rustc_middle::ty::{self, Ty, UpvarArgs};
use rustc_span::source_map::Spanned;
@@ -200,8 +199,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
{
let discr_ty = adt_def.repr().discr_type().to_ty(this.tcx);
let temp = unpack!(block = this.as_temp(block, scope, source, Mutability::Not));
let layout =
this.tcx.layout_of(this.typing_env().as_query_input(source_expr.ty));
let discr = this.temp(discr_ty, source_expr.span);
this.cfg.push_assign(
block,
@@ -209,80 +206,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
discr,
Rvalue::Discriminant(temp.into()),
);
let (op, ty) = (Operand::Move(discr), discr_ty);
if let BackendRepr::Scalar(scalar) = layout.unwrap().backend_repr
&& !scalar.is_always_valid(&this.tcx)
&& let Primitive::Int(int_width, _signed) = scalar.primitive()
{
let unsigned_ty = int_width.to_ty(this.tcx, false);
let unsigned_place = this.temp(unsigned_ty, expr_span);
this.cfg.push_assign(
block,
source_info,
unsigned_place,
Rvalue::Cast(CastKind::IntToInt, Operand::Copy(discr), unsigned_ty),
);
let bool_ty = this.tcx.types.bool;
let range = scalar.valid_range(&this.tcx);
let merge_op =
if range.start <= range.end { BinOp::BitAnd } else { BinOp::BitOr };
let mut comparer = |range: u128, bin_op: BinOp| -> Place<'tcx> {
// We can use `ty::TypingEnv::fully_monomorphized()` here
// as we only need it to compute the layout of a primitive.
let range_val = Const::from_bits(
this.tcx,
range,
ty::TypingEnv::fully_monomorphized(),
unsigned_ty,
);
let lit_op = this.literal_operand(expr.span, range_val);
let is_bin_op = this.temp(bool_ty, expr_span);
this.cfg.push_assign(
block,
source_info,
is_bin_op,
Rvalue::BinaryOp(
bin_op,
Box::new((Operand::Copy(unsigned_place), lit_op)),
),
);
is_bin_op
};
let assert_place = if range.start == 0 {
comparer(range.end, BinOp::Le)
} else {
let start_place = comparer(range.start, BinOp::Ge);
let end_place = comparer(range.end, BinOp::Le);
let merge_place = this.temp(bool_ty, expr_span);
this.cfg.push_assign(
block,
source_info,
merge_place,
Rvalue::BinaryOp(
merge_op,
Box::new((
Operand::Move(start_place),
Operand::Move(end_place),
)),
),
);
merge_place
};
this.cfg.push(
block,
Statement::new(
source_info,
StatementKind::Intrinsic(Box::new(NonDivergingIntrinsic::Assume(
Operand::Move(assert_place),
))),
),
);
}
(op, ty)
(Operand::Move(discr), discr_ty)
} else {
let ty = source_expr.ty;
let source = unpack!(