Enum cranelift_codegen::isa::ConstraintKind

pub enum ConstraintKind {
    Reg,
    FixedReg(RegUnit),
    Tied(u8),
    FixedTied(RegUnit),
    Stack,
}

The different kinds of operand constraints.

Variants

Reg

This operand or result must be a register from the given register class.

FixedReg(RegUnit)

This operand or result must be a fixed register.

The constraint’s regclass field is the top-level register class containing the fixed register.

Tied(u8)

This result value must use the same register as an input value operand.

The associated number is the index of the input value operand this result is tied to. The constraint’s regclass field is the same as the tied operand’s register class.

When an (in, out) operand pair is tied, this constraint kind appears in both the ins and the outs arrays. The constraint for the in operand is Tied(out), and the constraint for the out operand is Tied(in).

FixedTied(RegUnit)

This operand must be a fixed register, and it has a tied counterpart.

This works just like FixedReg, but additionally indicates that there are identical input/output operands for this fixed register. For an input operand, this means that the value will be clobbered by the instruction

Stack

This operand must be a value in a stack slot.

The constraint’s regclass field is the register class that would normally be used to load and store values of this type.

Trait Implementations

impl Clone for ConstraintKind

fn clone(&self) -> ConstraintKind

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Copy for ConstraintKind

impl Debug for ConstraintKind

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

Formats the value using the given formatter.

impl Eq for ConstraintKind

impl PartialEq<ConstraintKind> for ConstraintKind

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl StructuralEq for ConstraintKind

impl StructuralPartialEq for ConstraintKind