Enum Pass

#[repr(u8)]
pub enum Pass {
    CommonSubexpressionElimination = 1,
    ConstantCommuting = 2,
    ConstantFolding = 4,
    StrengthReduction = 8,
    DeadCodeElimination = 16,
    RegisterCoalescing = 128,
}

A standard optimization. Each pass applies a single optimization to a function. Each pass is represented as a single bit in a bitfield of passes. The passes are performed by the standard optimizer in definition order.

Variants

CommonSubexpressionElimination = 1

Eliminate common subexpressions by identifying and replacing identical expressions. Iterate until no further changes are made.

ConstantCommuting = 2

Commute immediate operands to the left side of instructions, thereby creating new opportunities for constant folding and strength reduction. Iterate until no further changes are made.

ConstantFolding = 4

Fold expressions with constant operands into immediates. Iterate until no further changes are made.

StrengthReduction = 8

Reduce the strength of expressions by replacing expensive operations with cheaper ones. Only a single iteration is performed.

DeadCodeElimination = 16

Eliminate dead code by removing instructions whose results are never used. Iterate until no further changes are made.

RegisterCoalescing = 128

Coalesce registers by merging equivalent registers. This pass breaks SSA form, so it is the final pass.

Trait Implementations

impl BitOr<Pass> for Passes

type Output = Passes

The resulting type after applying the | operator.

fn bitor(self, rhs: Pass) -> Self::Output

Performs the | operation.

impl BitOr<Passes> for Pass

type Output = Passes

The resulting type after applying the | operator.

fn bitor(self, rhs: Passes) -> Self::Output

Performs the | operation.

impl BitOr for Pass

type Output = Passes

The resulting type after applying the | operator.

fn bitor(self, rhs: Pass) -> Self::Output

Performs the | operation.

impl BitOrAssign<Pass> for Passes

fn bitor_assign(&mut self, rhs: Pass)

Performs the |= operation.

impl Clone for Pass

fn clone(&self) -> Pass

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Pass

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

Formats the value using the given formatter.

impl From<Pass> for Passes

fn from(pass: Pass) -> Self

Converts to this type from the input type.

impl PartialEq for Pass

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Pass

impl Eq for Pass

impl StructuralPartialEq for Pass