Enum Attribute

pub enum Attribute {
    KnownBits(Vec<Option<bool>>),
    PowerOfTwo,
    Negative,
    NonNegative,
    NonZero,
    HasExternalUses,
    SignBits(u8),
    Range(i128, i128),
}

Attributes describing data-flow facts known about a particular value or result of an instruction.

Variants

KnownBits(Vec<Option<bool>>)

Bits that are known to be set or unset.

The vector must have an entry for each bit in the value, e.g. if the value’s type is i32, then the vector’s length must be 32.

If the ith bit is known to be set, then the ith entry should be Some(true). If the ith bit is known to be unset, then the ith entry should be Some(false). If it is unknown whether the ith bit is set or unset, or it can sometimes be either, then the ith entry should be None.

PowerOfTwo

The value is known to be a power of two.

Negative

The value is known to be negative.

NonNegative

The value is known to be non-negative.

NonZero

The value is known to be non-zero.

HasExternalUses

The value is used by other expressions, not just this replacement’s expression DAG.

SignBits(u8)

It is known that there are n sign bits in this value.

Range(i128, i128)

This value is within the range .0 (inclusive) to .1 (exclusive).

Trait Implementations

impl Clone for Attribute

fn clone(&self) -> Attribute

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Attribute

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

Formats the value using the given formatter.

impl Display for Attribute

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

Formats the value using the given formatter.

impl Parse for Attribute

fn parse<'a>(parser: &mut Parser<'a>) -> Result<Self>

Parse a Self from the given buffer.

impl Peek for Attribute

fn peek<'a>(parser: &mut Parser<'a>) -> Result<bool>

Does it look like we can parse a Self from the given buffer?