Struct Chrec 

pub struct Chrec {
    pub base: Invariant,
    pub step: Invariant,
    pub ty: Type,
    pub flags: Flags,
}

An affine chain of recurrences, {base, +, step}, evolving in a named type.

The type is not decoration. {0, +, 1} in unsigned char is not the sequence 0, 1, 2, ..., it is that sequence modulo two hundred and fifty six, and section 7.7 says this is where a naive implementation is wrong constantly and in ways that pass every test written by someone thinking in int. Every operation here checks the type and every one that cannot stay right in it answers unknown.

Fields

base: Invariant

What the value is on the first iteration.

step: Invariant

What is added each time round.

ty: Type

The type it evolves in, which is what says when it wraps.

flags: Flags

What the instruction that increments it promised. nsw means the sequence does not wrap when read as signed and nuw means it does not when read as unsigned, and both come from the increment rather than from anything this analysis proved.

Implementations

impl Chrec

pub fn does_not_wrap(self, signed: bool) -> bool

Whether the sequence is known not to wrap under the reading this predicate takes.

Trait Implementations

impl Clone for Chrec

fn clone(&self) -> Chrec

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Chrec

impl Debug for Chrec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Chrec

impl PartialEq for Chrec

fn eq(&self, other: &Chrec) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Chrec