replace `&` with `&&` in {integer}::checked_rem

Using short-circuit operators makes it easier to perform some kinds of
source code analysis, like MC/DC code coverage (a requirement in
safety-critical environments). The optimized x86 assembly is the same
between the old and new versions:

```
xor eax, eax
test esi, esi
je .LBB0_1
cmp edi, -2147483648
jne .LBB0_4
cmp esi, -1
jne .LBB0_4
ret
.LBB0_1:
ret
.LBB0_4:
mov eax, edi
cdq
idiv esi
mov eax, 1
ret
```
This commit is contained in:
Pietro Albini 2021-10-27 15:45:31 +02:00
parent 81130fe188
commit 68a4460b61
No known key found for this signature in database
GPG Key ID: CD76B35F7734769E
1 changed files with 1 additions and 2 deletions

View File

@ -661,8 +661,7 @@ macro_rules! int_impl {
without modifying the original"]
#[inline]
pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
// Using `&` helps LLVM see that it is the same check made in division.
if unlikely!(rhs == 0 || ((self == Self::MIN) & (rhs == -1))) {
if unlikely!(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
None
} else {
// SAFETY: div by zero and by INT_MIN have been checked above