bjoernager/rust
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replace | with || in {unsigned_int}::borrowing_sub

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Using short-circuiting 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_64 assembly is the same
between the old and new versions:

```
mov eax, edi
add dl, -1
sbb eax, esi
setb dl
ret
```
This commit is contained in:
Pietro Albini 2021-10-27 16:56:57 +02:00
parent 5913ef6660
commit 9fb66969e3
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library/core/src/num/uint_macros.rs
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@ -1606,7 +1606,7 @@ macro_rules! uint_impl {
// to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic // to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic
let (a, b) = self.overflowing_sub(rhs); let (a, b) = self.overflowing_sub(rhs);
let (c, d) = a.overflowing_sub(borrow as $SelfT); let (c, d) = a.overflowing_sub(borrow as $SelfT);
(c, b | d) (c, b || d)
} }
/// Computes the absolute difference between `self` and `other`. /// Computes the absolute difference between `self` and `other`.