bjoernager/rust
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Fix handling of signed integers

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This commit is contained in:
varkor 2018-05-20 01:54:22 +01:00
parent b8702a0b1d
commit 121fa8d499
1 changed files with 44 additions and 12 deletions
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56
src/librustc_mir/hair/pattern/_match.rs
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@ -469,20 +469,16 @@ fn all_constructors<'a, 'tcx: 'a>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
ty::TyInt(int_ty) if exhaustive_integer_patterns => {
use syntax::ast::IntTy::*;
let (min, max, ty) = match int_ty {
Isize => (isize::MIN as i128, isize::MAX as i128, cx.tcx.types.isize),
I8 => ( i8::MIN as i128, i8::MAX as i128, cx.tcx.types.i8),
I16 => ( i16::MIN as i128, i16::MAX as i128, cx.tcx.types.i16),
I32 => ( i32::MIN as i128, i32::MAX as i128, cx.tcx.types.i32),
I64 => ( i64::MIN as i128, i64::MAX as i128, cx.tcx.types.i64),
I128 => ( i128::MIN as i128, i128::MAX as i128, cx.tcx.types.i128),
Isize => (isize::MIN as usize as u128, isize::MAX as usize as u128, cx.tcx.types.isize),
I8 => ( i8::MIN as u8 as u128, i8::MAX as u8 as u128, cx.tcx.types.i8),
I16 => ( i16::MIN as u16 as u128, i16::MAX as u16 as u128, cx.tcx.types.i16),
I32 => ( i32::MIN as u32 as u128, i32::MAX as u32 as u128, cx.tcx.types.i32),
I64 => ( i64::MIN as u64 as u128, i64::MAX as u64 as u128, cx.tcx.types.i64),
I128 => ( i128::MIN as u128 as u128, i128::MAX as u128 as u128, cx.tcx.types.i128),
};
value_constructors = true;
vec![ConstantRange(ty::Const::from_bits(cx.tcx, unsafe {
transmute::<i128, u128>(min)
}, ty),
ty::Const::from_bits(cx.tcx, unsafe {
transmute::<i128, u128>(max)
}, ty),
vec![ConstantRange(ty::Const::from_bits(cx.tcx, min, ty),
ty::Const::from_bits(cx.tcx, max, ty),
RangeEnd::Included)]
}
ty::TyUint(uint_ty) if exhaustive_integer_patterns => {
@ -628,6 +624,9 @@ impl<'tcx> Interval<'tcx> {
let ty = lo.ty;
if let Some(lo) = lo.assert_bits(ty) {
if let Some(hi) = hi.assert_bits(ty) {
// Perform a shift if the underlying types are signed,
// which makes the interval arithmetic simpler.
let (lo, hi) = Interval::offset_sign(ty, (lo, hi), true);
// Make sure the interval is well-formed.
return if lo > hi || lo == hi && *end == RangeEnd::Excluded {
None
@ -649,6 +648,38 @@ impl<'tcx> Interval<'tcx> {
}
}
fn offset_sign(ty: Ty<'tcx>, (lo, hi): (u128, u128), forwards: bool) -> (u128, u128) {
use syntax::ast::IntTy::*;
match ty.sty {
ty::TyInt(int_ty) => {
macro_rules! offset_sign_for_ty {
($ity:ty, $uty:ty, $min:expr) => {{
let min = Wrapping($min as $uty);
if forwards {
((Wrapping(lo as $uty) + min).0 as u128,
(Wrapping(hi as $uty) + min).0 as u128)
} else {
((Wrapping(lo as $uty) + min).0 as $ity as u128,
(Wrapping(hi as $uty) + min).0 as $ity as u128)
}
}}
}
match int_ty {
Isize => offset_sign_for_ty!(isize, usize, isize::MIN),
I8 => offset_sign_for_ty!(i8, u8, i8::MIN),
I16 => offset_sign_for_ty!(i16, u16, i16::MIN),
I32 => offset_sign_for_ty!(i32, u32, i32::MIN),
I64 => offset_sign_for_ty!(i64, u64, i64::MIN),
I128 => offset_sign_for_ty!(i128, u128, i128::MIN),
}
}
ty::TyUint(_) | ty::TyChar => {
(lo, hi)
}
_ => bug!("`Interval` should only contain integer types")
}
}
fn into_inner(self) -> (u128, u128) {
(self.lo, self.hi)
}
@ -692,6 +723,7 @@ fn ranges_subtract_pattern<'a, 'tcx>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
// Convert the remaining ranges from pairs to inclusive `ConstantRange`s.
let ty = pat_interval.ty;
remaining_ranges.into_iter().map(|(lo, hi)| {
let (lo, hi) = Interval::offset_sign(ty, (lo, hi), false);
ConstantRange(ty::Const::from_bits(cx.tcx, lo, ty),
ty::Const::from_bits(cx.tcx, hi, ty),
RangeEnd::Included)