diff --git a/nac3artiq/src/codegen.rs b/nac3artiq/src/codegen.rs
index e954070d..666a8e68 100644
--- a/nac3artiq/src/codegen.rs
+++ b/nac3artiq/src/codegen.rs
@@ -32,6 +32,7 @@ use pyo3::{
 
 use crate::{symbol_resolver::InnerResolver, timeline::TimeFns};
 
+use inkwell::values::IntValue;
 use itertools::Itertools;
 use std::{
     collections::{hash_map::DefaultHasher, HashMap},
@@ -544,7 +545,6 @@ fn format_rpc_ret<'ctx>(
     let llvm_i8 = ctx.ctx.i8_type();
     let llvm_i32 = ctx.ctx.i32_type();
     let llvm_pi8 = llvm_i8.ptr_type(AddressSpace::default());
-    let llvm_ppi8 = llvm_pi8.ptr_type(AddressSpace::default());
 
     let rpc_recv = ctx.module.get_function("rpc_recv").unwrap_or_else(|| {
         ctx.module.add_function("rpc_recv", llvm_i32.fn_type(&[llvm_pi8.into()], false), None)
@@ -568,6 +568,24 @@ fn format_rpc_ret<'ctx>(
             let llvm_i1 = ctx.ctx.bool_type();
             let llvm_usize = generator.get_size_type(ctx.ctx);
 
+            let round_up = |ctx: &mut CodeGenContext<'ctx, '_>,
+                            val: IntValue<'ctx>,
+                            power_of_two: IntType<'ctx>| {
+                debug_assert!((power_of_two.get_bit_width() / 8).is_power_of_two());
+
+                let llvm_val_t = val.get_type();
+
+                let max_rem = (power_of_two.get_bit_width() / 8) - 1;
+                let max_rem = llvm_val_t.const_int(max_rem as u64, false);
+                ctx.builder
+                    .build_and(
+                        ctx.builder.build_int_add(val, max_rem, "").unwrap(),
+                        ctx.builder.build_not(max_rem, "").unwrap(),
+                        "",
+                    )
+                    .unwrap()
+            };
+
             let (elem_ty, ndims) = unpack_ndarray_var_tys(&mut ctx.unifier, ret_ty);
             let llvm_elem_ty = ctx.get_llvm_type(generator, elem_ty);
             let llvm_ret_ty = NDArrayType::new(generator, ctx.ctx, llvm_elem_ty);
@@ -602,6 +620,8 @@ fn format_rpc_ret<'ctx>(
 
             let buffer_size =
                 ctx.builder.build_int_add(dims_buf_sz, llvm_pdata_sizeof, "").unwrap();
+            // let buffer_size = round_up(ctx, buffer_size, ctx.ctx.i64_type());a
+            let buffer_size = llvm_usize.const_int(16, false);
 
             let buffer =
                 ctx.builder.build_array_alloca(llvm_pi8, buffer_size, "rpc.buffer").unwrap();