unsafe fn compare_keys(
        &mut self,
        builder: LLVMBuilderRef,
        slot_key: LLVMValueRef,
        key: LLVMValueRef,
    ) -> LLVMValueRef {
        let mut args = [slot_key, key];
        LLVMBuildCall(
            builder,
            self.key_comparator,
            args.as_mut_ptr(),
            args.len() as u32,
            c_str!(""),
        )
    }
Returns whether two keys are equal using their equality function.
weld/src/codegen/llvm2/dict.rs