diff --git a/crates/compiler/gen_dev/src/generic64/x86_64.rs b/crates/compiler/gen_dev/src/generic64/x86_64.rs
index 05520a3c79..a34dc54d74 100644
--- a/crates/compiler/gen_dev/src/generic64/x86_64.rs
+++ b/crates/compiler/gen_dev/src/generic64/x86_64.rs
@@ -490,6 +490,24 @@ impl X64_64SystemVStoreArgs {
                         sym,
                         lambda_set.runtime_representation(),
                     ),
+                    Layout::Struct { .. } => {
+                        // for now, just also store this on the stack
+                        let (base_offset, size) = storage_manager.stack_offset_and_size(&sym);
+                        debug_assert_eq!(base_offset % 8, 0);
+                        for i in (0..size as i32).step_by(8) {
+                            X86_64Assembler::mov_reg64_base32(
+                                buf,
+                                Self::GENERAL_RETURN_REGS[0],
+                                base_offset + i,
+                            );
+                            X86_64Assembler::mov_stack32_reg64(
+                                buf,
+                                self.tmp_stack_offset + i,
+                                Self::GENERAL_RETURN_REGS[0],
+                            );
+                        }
+                        self.tmp_stack_offset += size as i32;
+                    }
                     _ => {
                         todo!("calling with arg type, {:?}", layout_interner.dbg(other));
                     }
@@ -589,6 +607,11 @@ impl X64_64SystemVLoadArgs {
                     sym,
                     lambda_set.runtime_representation(),
                 ),
+                Layout::Struct { .. } => {
+                    // for now, just also store this on the stack
+                    storage_manager.complex_stack_arg(&sym, self.argument_offset, stack_size);
+                    self.argument_offset += stack_size as i32;
+                }
                 _ => {
                     dbg!(other, layout_interner.get(other));
                     todo!("Loading args with layout {:?}", layout_interner.dbg(other));
diff --git a/crates/compiler/gen_dev/src/lib.rs b/crates/compiler/gen_dev/src/lib.rs
index ffd99b95e6..cba9e3e107 100644
--- a/crates/compiler/gen_dev/src/lib.rs
+++ b/crates/compiler/gen_dev/src/lib.rs
@@ -868,6 +868,13 @@ trait Backend<'a> {
                 arg_layouts,
                 ret_layout,
             ),
+            LowLevel::StrToUtf8 => self.build_fn_call(
+                sym,
+                bitcode::STR_TO_UTF8.to_string(),
+                args,
+                arg_layouts,
+                ret_layout,
+            ),
             LowLevel::StrCountUtf8Bytes => self.build_fn_call(
                 sym,
                 bitcode::STR_COUNT_UTF8_BYTES.to_string(),
diff --git a/crates/compiler/test_gen/src/gen_str.rs b/crates/compiler/test_gen/src/gen_str.rs
index ee4c4dabd9..7edfe16a1b 100644
--- a/crates/compiler/test_gen/src/gen_str.rs
+++ b/crates/compiler/test_gen/src/gen_str.rs
@@ -891,7 +891,7 @@ fn str_join_comma_single() {
 }
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-dev"))]
 fn str_to_utf8() {
     assert_evals_to!(
         r#"Str.toUtf8 "hello""#,
@@ -909,7 +909,7 @@ fn str_to_utf8() {
 }
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-dev"))]
 fn str_from_utf8_range() {
     assert_evals_to!(
         indoc!(
@@ -926,7 +926,7 @@ fn str_from_utf8_range() {
 }
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-dev"))]
 fn str_from_utf8_range_slice() {
     assert_evals_to!(
         indoc!(
@@ -943,7 +943,7 @@ fn str_from_utf8_range_slice() {
 }
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-dev"))]
 fn str_from_utf8_range_slice_not_end() {
     assert_evals_to!(
         indoc!(
@@ -960,7 +960,7 @@ fn str_from_utf8_range_slice_not_end() {
 }
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-dev"))]
 fn str_from_utf8_range_order_does_not_matter() {
     assert_evals_to!(
         indoc!(
@@ -977,7 +977,7 @@ fn str_from_utf8_range_order_does_not_matter() {
 }
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-dev"))]
 fn str_from_utf8_range_out_of_bounds_start_value() {
     assert_evals_to!(
         indoc!(
@@ -995,7 +995,7 @@ fn str_from_utf8_range_out_of_bounds_start_value() {
 }
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-dev"))]
 fn str_from_utf8_range_count_too_high() {
     assert_evals_to!(
         indoc!(
@@ -1013,7 +1013,7 @@ fn str_from_utf8_range_count_too_high() {
 }
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-dev"))]
 fn str_from_utf8_range_count_too_high_for_start() {
     assert_evals_to!(
         indoc!(