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Rollup merge of #111579 - scottmcm:enum-as-signed, r=oli-obk

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Also assume wrap-around discriminants in `as` MIR building

Resolves this FIXME:

8d18c32b61/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs (L231)

r? `@oli-obk`
This commit is contained in:
Dylan DPC 2023-05-23 16:44:27 +05:30 • committed by GitHub
commit 00185bec7c
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11 changed files with 234 additions and 67 deletions
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101
compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
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@ -15,6 +15,7 @@ use rustc_middle::mir::Place;
use rustc_middle::mir::*;
use rustc_middle::thir::*;
use rustc_middle::ty::cast::{mir_cast_kind, CastTy};
use rustc_middle::ty::layout::IntegerExt;
use rustc_middle::ty::{self, Ty, UpvarSubsts};
use rustc_span::Span;
@ -225,49 +226,63 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
);
let (op,ty) = (Operand::Move(discr), discr_ty);
if let Abi::Scalar(scalar) = layout.unwrap().abi{
if let Primitive::Int(_, signed) = scalar.primitive() {
let range = scalar.valid_range(&this.tcx);
// FIXME: Handle wraparound cases too.
if range.end >= range.start {
let mut assumer = |range: u128, bin_op: BinOp| {
// We will be overwriting this val if our scalar is signed value
// because sign extension on unsigned types might cause unintended things
let mut range_val =
ConstantKind::from_bits(this.tcx, range, ty::ParamEnv::empty().and(discr_ty));
let bool_ty = this.tcx.types.bool;
if signed {
let scalar_size_extend = scalar.size(&this.tcx).sign_extend(range);
let discr_layout = this.tcx.layout_of(this.param_env.and(discr_ty));
let truncated_val = discr_layout.unwrap().size.truncate(scalar_size_extend);
range_val = ConstantKind::from_bits(
this.tcx,
truncated_val,
ty::ParamEnv::empty().and(discr_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(((lit_op), (Operand::Copy(discr))))),
);
this.cfg.push(
block,
Statement {
source_info,
kind: StatementKind::Intrinsic(Box::new(NonDivergingIntrinsic::Assume(
Operand::Copy(is_bin_op),
))),
},
)
};
assumer(range.end, BinOp::Ge);
assumer(range.start, BinOp::Le);
}
}
if let Abi::Scalar(scalar) = layout.unwrap().abi
&& !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> {
let range_val =
ConstantKind::from_bits(this.tcx, range, ty::ParamEnv::empty().and(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 {
source_info,
kind: StatementKind::Intrinsic(Box::new(NonDivergingIntrinsic::Assume(
Operand::Move(assert_place),
))),
},
);
}
(op,ty)