Method derived

cranelift/codegen/meta/src/cdsl/typevar.rs:147–238

Create a type variable that is a function of another.

(&self, derived_func: DerivedFunc)

    /// Create a type variable that is a function of another.
    pub fn derived(&self, derived_func: DerivedFunc) -> TypeVar {
        let ts = self.get_typeset();

        // Safety checks to avoid over/underflows.
        match derived_func {
            DerivedFunc::HalfWidth => {
                assert!(
                    ts.ints.is_empty() || *ts.ints.iter().min().unwrap() > 8,
                    "can't halve all integer types"
                );
                assert!(
                    ts.floats.is_empty() || *ts.floats.iter().min().unwrap() > 16,
                    "can't halve all float types"
                );
            }
            DerivedFunc::DoubleWidth => {
                assert!(
                    ts.ints.is_empty() || *ts.ints.iter().max().unwrap() < MAX_BITS,
                    "can't double all integer types"
                );
                assert!(
                    ts.floats.is_empty() || *ts.floats.iter().max().unwrap() < MAX_FLOAT_BITS,
                    "can't double all float types"
                );
            }
            DerivedFunc::SplitLanes => {
                assert!(
                    ts.ints.is_empty() || *ts.ints.iter().min().unwrap() > 8,
                    "can't halve all integer types"
                );
                assert!(
                    ts.floats.is_empty() || *ts.floats.iter().min().unwrap() > 16,
                    "can't halve all float types"
                );
                assert!(
                    *ts.lanes.iter().max().unwrap() < MAX_LANES,
                    "can't double 256 lanes"
                );
            }
            DerivedFunc::MergeLanes => {
                assert!(
                    ts.ints.is_empty() || *ts.ints.iter().max().unwrap() < MAX_BITS,
                    "can't double all integer types"
                );
                assert!(
                    ts.floats.is_empty() || *ts.floats.iter().max().unwrap() < MAX_FLOAT_BITS,
                    "can't double all float types"
                );
                assert!(
                    *ts.lanes.iter().min().unwrap() > 1,
                    "can't halve a scalar type"
                );
            }
            DerivedFunc::Narrower => {
                assert_eq!(
                    *ts.lanes.iter().max().unwrap(),
                    1,
                    "The `narrower` constraint does not apply to vectors"