Method ctrl_typevar

cranelift/codegen/src/ir/dfg.rs:1214–1235

Get the controlling type variable, or `INVALID` if `inst` isn't polymorphic.

(&self, inst: Inst)

    /// Get the controlling type variable, or `INVALID` if `inst` isn't polymorphic.
    pub fn ctrl_typevar(&self, inst: Inst) -> Type {
        let constraints = self.insts[inst].opcode().constraints();

        if !constraints.is_polymorphic() {
            types::INVALID
        } else if constraints.requires_typevar_operand() {
            // Not all instruction formats have a designated operand, but in that case
            // `requires_typevar_operand()` should never be true.
            self.value_type(
                self.insts[inst]
                    .typevar_operand(&self.value_lists)
                    .unwrap_or_else(|| {
                        panic!(
                            "Instruction format for {:?} doesn't have a designated operand",
                            self.insts[inst]
                        )
                    }),
            )
        } else {
            self.value_type(self.first_result(inst))
        }
    }
}

/// basic blocks.