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Expand assumes to the other unchecked slice ops #120762

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Expand assumes to the other unchecked slice ops #120762

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17 changes: 14 additions & 3 deletions library/core/src/slice/index.rs
View file
Original file line number Diff line number Diff line change
@@ -265,7 +265,10 @@ unsafe impl<T> SliceIndex<[T]> for usize {
(this: usize = self, len: usize = slice.len()) => this < len
);
// SAFETY: see comments for `get_unchecked` above.
unsafe { get_mut_noubcheck(slice, self) }
unsafe {
crate::intrinsics::assume(self < slice.len());
get_mut_noubcheck(slice, self)
}
}

#[inline]
@@ -317,7 +320,10 @@ unsafe impl<T> SliceIndex<[T]> for ops::IndexRange {
// cannot be longer than `isize::MAX`. They also guarantee that
// `self` is in bounds of `slice` so `self` cannot overflow an `isize`,
// so the call to `add` is safe.
unsafe { get_offset_len_noubcheck(slice, self.start(), self.len()) }
unsafe {
crate::intrinsics::assume(self.end() <= slice.len());
get_offset_len_noubcheck(slice, self.start(), self.len())
}
}

#[inline]
@@ -329,7 +335,10 @@ unsafe impl<T> SliceIndex<[T]> for ops::IndexRange {
);

// SAFETY: see comments for `get_unchecked` above.
unsafe { get_offset_len_mut_noubcheck(slice, self.start(), self.len()) }
unsafe {
crate::intrinsics::assume(self.end() <= slice.len());
get_offset_len_mut_noubcheck(slice, self.start(), self.len())
}
}

#[inline]
@@ -404,6 +413,7 @@ unsafe impl<T> SliceIndex<[T]> for ops::Range<usize> {
unsafe {
// Using the intrinsic avoids a superfluous UB check,
// since the one on this method already checked `end >= start`.
crate::intrinsics::assume(self.end <= slice.len());
let new_len = crate::intrinsics::unchecked_sub(self.end, self.start);
get_offset_len_noubcheck(slice, self.start, new_len)
}
@@ -422,6 +432,7 @@ unsafe impl<T> SliceIndex<[T]> for ops::Range<usize> {
);
// SAFETY: see comments for `get_unchecked` above.
unsafe {
crate::intrinsics::assume(self.end <= slice.len());
let new_len = crate::intrinsics::unchecked_sub(self.end, self.start);
get_offset_len_mut_noubcheck(slice, self.start, new_len)
}
24 changes: 24 additions & 0 deletions tests/codegen/issues/issue-116878.rs
View file
Original file line number Diff line number Diff line change
@@ -9,3 +9,27 @@ pub unsafe fn unchecked_slice_no_bounds_check(s: &[u8]) -> u8 {
// CHECK-NOT: panic_bounds_check
a + s[0]
}

// CHECK-LABEL: @unchecked_slice_no_bounds_check_mut
#[no_mangle]
pub unsafe fn unchecked_slice_no_bounds_check_mut(s: &mut [u8]) -> u8 {
let a = *s.get_unchecked_mut(2);
// CHECK-NOT: panic_bounds_check
a + s[1]
}

// CHECK-LABEL: @unchecked_slice_no_bounds_check_range
#[no_mangle]
pub unsafe fn unchecked_slice_no_bounds_check_range(s: &[u8]) -> u8 {
let _a = &s.get_unchecked(..1);
// CHECK-NOT: panic_bounds_check
s[0]
}

// CHECK-LABEL: @unchecked_slice_no_bounds_check_range_mut
#[no_mangle]
pub unsafe fn unchecked_slice_no_bounds_check_range_mut(s: &mut [u8]) -> u8 {
let _a = &mut s.get_unchecked_mut(..2);
// CHECK-NOT: panic_bounds_check
s[1]
}
49 changes: 31 additions & 18 deletions ...pt/pre-codegen/slice_index.slice_get_unchecked_mut_range.PreCodegen.after.panic-abort.mir
View file
Original file line number Diff line number Diff line change
@@ -8,19 +8,21 @@ fn slice_get_unchecked_mut_range(_1: &mut [u32], _2: std::ops::Range<usize>) ->
let mut _4: usize;
scope 1 (inlined core::slice::<impl [u32]>::get_unchecked_mut::<std::ops::Range<usize>>) {
let mut _5: *mut [u32];
let mut _11: *mut [u32];
let mut _13: *mut [u32];
scope 2 (inlined <std::ops::Range<usize> as SliceIndex<[u32]>>::get_unchecked_mut) {
let mut _6: usize;
let _7: ();
let _8: usize;
let mut _8: usize;
let mut _9: bool;
let _10: usize;
scope 3 {
scope 6 (inlined core::slice::index::get_offset_len_mut_noubcheck::<u32>) {
let _10: *mut u32;
scope 7 {
scope 8 (inlined core::slice::index::get_offset_len_mut_noubcheck::<u32>) {
let _12: *mut u32;
scope 9 {
}
scope 8 (inlined core::slice::index::get_mut_noubcheck::<u32>) {
let _9: *mut u32;
scope 9 {
scope 10 (inlined core::slice::index::get_mut_noubcheck::<u32>) {
let _11: *mut u32;
scope 11 {
}
}
}
@@ -29,35 +31,46 @@ fn slice_get_unchecked_mut_range(_1: &mut [u32], _2: std::ops::Range<usize>) ->
scope 5 (inlined std::ptr::metadata::<[u32]>) {
}
}
scope 6 (inlined std::ptr::mut_ptr::<impl *mut [u32]>::len) {
scope 7 (inlined std::ptr::metadata::<[u32]>) {
}
}
}
}

bb0: {
_3 = move (_2.0: usize);
_4 = move (_2.1: usize);
StorageLive(_11);
StorageLive(_13);
StorageLive(_5);
_5 = &raw mut (*_1);
StorageLive(_8);
StorageLive(_10);
StorageLive(_6);
_6 = PtrMetadata(copy _1);
_7 = <std::ops::Range<usize> as SliceIndex<[T]>>::get_unchecked_mut::precondition_check(copy _3, copy _4, move _6) -> [return: bb1, unwind unreachable];
}

bb1: {
StorageDead(_6);
_8 = SubUnchecked(copy _4, copy _3);
StorageLive(_10);
StorageLive(_9);
_9 = copy _5 as *mut u32 (PtrToPtr);
_10 = Offset(copy _9, copy _3);
StorageLive(_8);
_8 = PtrMetadata(copy _1);
_9 = Le(copy _4, move _8);
StorageDead(_8);
assume(move _9);
StorageDead(_9);
_11 = *mut [u32] from (copy _10, copy _8);
_10 = SubUnchecked(copy _4, copy _3);
StorageLive(_12);
StorageLive(_11);
_11 = copy _5 as *mut u32 (PtrToPtr);
_12 = Offset(copy _11, copy _3);
StorageDead(_11);
_13 = *mut [u32] from (copy _12, copy _10);
StorageDead(_12);
StorageDead(_10);
StorageDead(_8);
StorageDead(_5);
_0 = &mut (*_11);
StorageDead(_11);
_0 = &mut (*_13);
StorageDead(_13);
return;
}
}
49 changes: 31 additions & 18 deletions ...t/pre-codegen/slice_index.slice_get_unchecked_mut_range.PreCodegen.after.panic-unwind.mir
View file
Original file line number Diff line number Diff line change
@@ -8,19 +8,21 @@ fn slice_get_unchecked_mut_range(_1: &mut [u32], _2: std::ops::Range<usize>) ->
let mut _4: usize;
scope 1 (inlined core::slice::<impl [u32]>::get_unchecked_mut::<std::ops::Range<usize>>) {
let mut _5: *mut [u32];
let mut _11: *mut [u32];
let mut _13: *mut [u32];
scope 2 (inlined <std::ops::Range<usize> as SliceIndex<[u32]>>::get_unchecked_mut) {
let mut _6: usize;
let _7: ();
let _8: usize;
let mut _8: usize;
let mut _9: bool;
let _10: usize;
scope 3 {
scope 6 (inlined core::slice::index::get_offset_len_mut_noubcheck::<u32>) {
let _10: *mut u32;
scope 7 {
scope 8 (inlined core::slice::index::get_offset_len_mut_noubcheck::<u32>) {
let _12: *mut u32;
scope 9 {
}
scope 8 (inlined core::slice::index::get_mut_noubcheck::<u32>) {
let _9: *mut u32;
scope 9 {
scope 10 (inlined core::slice::index::get_mut_noubcheck::<u32>) {
let _11: *mut u32;
scope 11 {
}
}
}
@@ -29,35 +31,46 @@ fn slice_get_unchecked_mut_range(_1: &mut [u32], _2: std::ops::Range<usize>) ->
scope 5 (inlined std::ptr::metadata::<[u32]>) {
}
}
scope 6 (inlined std::ptr::mut_ptr::<impl *mut [u32]>::len) {
scope 7 (inlined std::ptr::metadata::<[u32]>) {
}
}
}
}

bb0: {
_3 = move (_2.0: usize);
_4 = move (_2.1: usize);
StorageLive(_11);
StorageLive(_13);
StorageLive(_5);
_5 = &raw mut (*_1);
StorageLive(_8);
StorageLive(_10);
StorageLive(_6);
_6 = PtrMetadata(copy _1);
_7 = <std::ops::Range<usize> as SliceIndex<[T]>>::get_unchecked_mut::precondition_check(copy _3, copy _4, move _6) -> [return: bb1, unwind unreachable];
}

bb1: {
StorageDead(_6);
_8 = SubUnchecked(copy _4, copy _3);
StorageLive(_10);
StorageLive(_9);
_9 = copy _5 as *mut u32 (PtrToPtr);
_10 = Offset(copy _9, copy _3);
StorageLive(_8);
_8 = PtrMetadata(copy _1);
_9 = Le(copy _4, move _8);
StorageDead(_8);
assume(move _9);
StorageDead(_9);
_11 = *mut [u32] from (copy _10, copy _8);
_10 = SubUnchecked(copy _4, copy _3);
StorageLive(_12);
StorageLive(_11);
_11 = copy _5 as *mut u32 (PtrToPtr);
_12 = Offset(copy _11, copy _3);
StorageDead(_11);
_13 = *mut [u32] from (copy _12, copy _10);
StorageDead(_12);
StorageDead(_10);
StorageDead(_8);
StorageDead(_5);
_0 = &mut (*_11);
StorageDead(_11);
_0 = &mut (*_13);
StorageDead(_13);
return;
}
}
41 changes: 27 additions & 14 deletions ...pt/pre-codegen/slice_index.slice_ptr_get_unchecked_range.PreCodegen.after.panic-abort.mir
View file
Original file line number Diff line number Diff line change
@@ -10,15 +10,17 @@ fn slice_ptr_get_unchecked_range(_1: *const [u32], _2: std::ops::Range<usize>) -
scope 2 (inlined <std::ops::Range<usize> as SliceIndex<[u32]>>::get_unchecked) {
let mut _5: usize;
let _6: ();
let _7: usize;
let mut _7: usize;
let mut _8: bool;
let _9: usize;
scope 3 {
scope 6 (inlined core::slice::index::get_offset_len_noubcheck::<u32>) {
let _9: *const u32;
scope 7 {
scope 8 (inlined core::slice::index::get_offset_len_noubcheck::<u32>) {
let _11: *const u32;
scope 9 {
}
scope 8 (inlined core::slice::index::get_noubcheck::<u32>) {
let _8: *const u32;
scope 9 {
scope 10 (inlined core::slice::index::get_noubcheck::<u32>) {
let _10: *const u32;
scope 11 {
}
}
}
@@ -27,29 +29,40 @@ fn slice_ptr_get_unchecked_range(_1: *const [u32], _2: std::ops::Range<usize>) -
scope 5 (inlined std::ptr::metadata::<[u32]>) {
}
}
scope 6 (inlined std::ptr::const_ptr::<impl *const [u32]>::len) {
scope 7 (inlined std::ptr::metadata::<[u32]>) {
}
}
}
}

bb0: {
_3 = move (_2.0: usize);
_4 = move (_2.1: usize);
StorageLive(_7);
StorageLive(_9);
StorageLive(_5);
_5 = PtrMetadata(copy _1);
_6 = <std::ops::Range<usize> as SliceIndex<[T]>>::get_unchecked::precondition_check(copy _3, copy _4, move _5) -> [return: bb1, unwind unreachable];
}

bb1: {
StorageDead(_5);
_7 = SubUnchecked(copy _4, copy _3);
StorageLive(_9);
StorageLive(_8);
_8 = copy _1 as *const u32 (PtrToPtr);
_9 = Offset(copy _8, copy _3);
StorageLive(_7);
_7 = PtrMetadata(copy _1);
_8 = Le(copy _4, move _7);
StorageDead(_7);
assume(move _8);
StorageDead(_8);
_0 = *const [u32] from (copy _9, copy _7);
_9 = SubUnchecked(copy _4, copy _3);
StorageLive(_11);
StorageLive(_10);
_10 = copy _1 as *const u32 (PtrToPtr);
_11 = Offset(copy _10, copy _3);
StorageDead(_10);
_0 = *const [u32] from (copy _11, copy _9);
StorageDead(_11);
StorageDead(_9);
StorageDead(_7);
return;
}
}
41 changes: 27 additions & 14 deletions ...t/pre-codegen/slice_index.slice_ptr_get_unchecked_range.PreCodegen.after.panic-unwind.mir
View file
Original file line number Diff line number Diff line change
@@ -10,15 +10,17 @@ fn slice_ptr_get_unchecked_range(_1: *const [u32], _2: std::ops::Range<usize>) -
scope 2 (inlined <std::ops::Range<usize> as SliceIndex<[u32]>>::get_unchecked) {
let mut _5: usize;
let _6: ();
let _7: usize;
let mut _7: usize;
let mut _8: bool;
let _9: usize;
scope 3 {
scope 6 (inlined core::slice::index::get_offset_len_noubcheck::<u32>) {
let _9: *const u32;
scope 7 {
scope 8 (inlined core::slice::index::get_offset_len_noubcheck::<u32>) {
let _11: *const u32;
scope 9 {
}
scope 8 (inlined core::slice::index::get_noubcheck::<u32>) {
let _8: *const u32;
scope 9 {
scope 10 (inlined core::slice::index::get_noubcheck::<u32>) {
let _10: *const u32;
scope 11 {
}
}
}
@@ -27,29 +29,40 @@ fn slice_ptr_get_unchecked_range(_1: *const [u32], _2: std::ops::Range<usize>) -
scope 5 (inlined std::ptr::metadata::<[u32]>) {
}
}
scope 6 (inlined std::ptr::const_ptr::<impl *const [u32]>::len) {
scope 7 (inlined std::ptr::metadata::<[u32]>) {
}
}
}
}

bb0: {
_3 = move (_2.0: usize);
_4 = move (_2.1: usize);
StorageLive(_7);
StorageLive(_9);
StorageLive(_5);
_5 = PtrMetadata(copy _1);
_6 = <std::ops::Range<usize> as SliceIndex<[T]>>::get_unchecked::precondition_check(copy _3, copy _4, move _5) -> [return: bb1, unwind unreachable];
}

bb1: {
StorageDead(_5);
_7 = SubUnchecked(copy _4, copy _3);
StorageLive(_9);
StorageLive(_8);
_8 = copy _1 as *const u32 (PtrToPtr);
_9 = Offset(copy _8, copy _3);
StorageLive(_7);
_7 = PtrMetadata(copy _1);
_8 = Le(copy _4, move _7);
StorageDead(_7);
assume(move _8);
StorageDead(_8);
_0 = *const [u32] from (copy _9, copy _7);
_9 = SubUnchecked(copy _4, copy _3);
StorageLive(_11);
StorageLive(_10);
_10 = copy _1 as *const u32 (PtrToPtr);
_11 = Offset(copy _10, copy _3);
StorageDead(_10);
_0 = *const [u32] from (copy _11, copy _9);
StorageDead(_11);
StorageDead(_9);
StorageDead(_7);
return;
}
}
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