feat: Separate runtimes of SSA functions before inlining (#5121)

# Description ## Problem\* Resolves #5043 <details> <summary>Opcode count of Aztec public functions before => after this change in the inlining strategy</summary> ``` _approve_bridge_and_exit_input_asset_to_L1 on contract Uniswap with size 3788 => 3166 _assert_token_is_same on contract TokenBridge with size 916 => 640 _assert_token_is_same on contract Uniswap with size 1845 => 1546 _borrow on contract Lending with size 10988 => 10152 _call_mint_on_token on contract TokenBridge with size 1427 => 1125 _check_deadline on contract Crowdfunding with size 1015 => 752 _deposit on contract Lending with size 1699 => 1220 _increase_public_balance on contract GasToken with size 1325 => 1103 _increase_public_balance on contract Token with size 1577 => 1201 _increase_public_balance on contract TokenBlacklist with size 1577 => 1201 _reduce_total_supply on contract Token with size 945 => 626 _reduce_total_supply on contract TokenBlacklist with size 945 => 626 _repay on contract Lending with size 6775 => 6284 _withdraw on contract Lending with size 10715 => 9850 add_args_return on contract AvmNestedCallsTest with size 15 => 15 add_args_return on contract AvmTest with size 15 => 15 add_storage_map on contract AvmTest with size 797 => 664 add_to_tally_public on contract EasyPrivateVoting with size 1496 => 1112 add_u128 on contract AvmTest with size 187 => 187 admin on contract Token with size 495 => 348 approve_public_authwit on contract EcdsaAccount with size 977 => 718 approve_public_authwit on contract SchnorrAccount with size 743 => 621 approve_public_authwit on contract SchnorrHardcodedAccount with size 742 => 620 approve_public_authwit on contract SchnorrSingleKeyAccount with size 742 => 620 assert_block_number on contract AppSubscription with size 920 => 669 assert_minter_and_mint on contract Token with size 1434 => 1035 assert_not_expired on contract AppSubscription with size 910 => 658 assert_nullifier_exists on contract AvmTest with size 242 => 156 assert_public_global_vars on contract Test with size 1054 => 679 assert_same on contract AvmNestedCallsTest with size 138 => 138 assert_unsiloed_nullifier_acvm on contract AvmAcvmInteropTest with size 102 => 16 assertion_failure on contract AvmTest with size 166 => 166 avm_to_acvm_call on contract AvmAcvmInteropTest with size 287 => 169 balance_of_public on contract GasToken with size 651 => 612 balance_of_public on contract Token with size 880 => 710 balance_of_public on contract TokenBlacklist with size 880 => 710 borrow_public on contract Lending with size 1193 => 939 broadcast on contract Benchmarking with size 419 => 337 burn_public on contract Token with size 2426 => 1962 burn_public on contract TokenBlacklist with size 3148 => 2468 call_acvm_from_avm on contract AvmAcvmInteropTest with size 574 => 503 call_avm_from_acvm on contract AvmAcvmInteropTest with size 578 => 507 check_balance on contract GasToken with size 856 => 768 check_selector on contract AvmTest with size 463 => 463 claim_public on contract GasToken with size 3963 => 3416 claim_public on contract TokenBridge with size 4176 => 3457 constant_field_acvm on contract AvmAcvmInteropTest with size 13 => 13 constant_field_avm on contract AvmAcvmInteropTest with size 13 => 13 constructor on contract AppSubscription with size 3376 => 1983 constructor on contract Auth with size 1414 => 994 constructor on contract AvmInitializerTest with size 1290 => 908 constructor on contract Claim with size 1700 => 1123 constructor on contract EasyPrivateVoting with size 1454 => 941 constructor on contract FPC with size 1700 => 1123 constructor on contract InclusionProofs with size 1021 => 704 constructor on contract Token with size 2737 => 1961 constructor on contract TokenBlacklist with size 1925 => 1285 constructor on contract TokenBridge with size 1400 => 924 constructor on contract Uniswap with size 1326 => 909 consume_message_from_arbitrary_sender_public on contract Test with size 2203 => 1893 consume_mint_public_message on contract Test with size 2910 => 2600 create_different_nullifier_in_nested_call on contract AvmNestedCallsTest with size 743 => 639 create_l2_to_l1_message_arbitrary_recipient_public on contract Test with size 56 => 12 create_l2_to_l1_message_public on contract Test with size 73 => 29 create_same_nullifier_in_nested_call on contract AvmNestedCallsTest with size 741 => 637 debug_logging on contract AvmTest with size 725 => 402 deposit_public on contract Lending with size 2286 => 1846 dummy_public_call on contract Test with size 354 => 284 emit_nullifier_and_check on contract AvmTest with size 436 => 314 emit_nullifier_public on contract Test with size 47 => 11 emit_unencrypted on contract Test with size 54 => 16 emit_unencrypted_log on contract AvmTest with size 757 => 685 end_vote on contract EasyPrivateVoting with size 514 => 279 exit_to_l1_public on contract TokenBridge with size 2154 => 1773 get_address on contract AvmTest with size 45 => 13 get_args_hash on contract AvmTest with size 18 => 18 get_asset on contract Lending with size 888 => 718 get_assets on contract Lending with size 587 => 411 get_authorized on contract Auth with size 597 => 443 get_authorized_delay on contract Auth with size 702 => 517 get_block_number on contract AvmTest with size 45 => 13 get_chain_id on contract AvmTest with size 45 => 13 get_fee_per_da_gas on contract AvmTest with size 45 => 13 get_fee_per_l2_gas on contract AvmTest with size 45 => 13 get_portal_address_public on contract TokenBridge with size 297 => 145 get_position on contract Lending with size 3908 => 3623 get_price on contract PriceFeed with size 617 => 579 get_public_value on contract StatefulTest with size 636 => 598 get_roles on contract TokenBlacklist with size 989 => 749 get_scheduled_authorized on contract Auth with size 595 => 443 get_sender on contract AvmTest with size 45 => 13 get_shared_immutable_constrained_public on contract DocsExample with size 438 => 406 get_shared_immutable_constrained_public_indirect on contract DocsExample with size 701 => 607 get_shared_immutable_constrained_public_multiple on contract DocsExample with size 136 => 98 get_storage_address on contract AvmTest with size 45 => 13 get_timestamp on contract AvmTest with size 45 => 13 get_token on contract TokenBridge with size 513 => 366 get_transaction_fee on contract AvmTest with size 45 => 13 get_version on contract AvmTest with size 45 => 13 increment_balance on contract Benchmarking with size 1472 => 1264 increment_public_value on contract StatefulTest with size 695 => 449 increment_public_value_no_init_check on contract StatefulTest with size 447 => 351 init on contract Crowdfunding with size 2100 => 1341 init on contract Lending with size 958 => 598 initialize_public_immutable on contract DocsExample with size 433 => 252 initialize_shared_immutable on contract DocsExample with size 433 => 252 is_minter on contract Token with size 838 => 668 is_time_equal on contract Test with size 56 => 18 keccak_hash on contract AvmTest with size 49 => 49 l1_to_l2_msg_exists on contract AvmTest with size 65 => 17 mint_private on contract Token with size 1247 => 790 mint_private on contract TokenBlacklist with size 1495 => 906 mint_public on contract GasToken with size 946 => 813 mint_public on contract Token with size 2048 => 1520 mint_public on contract TokenBlacklist with size 2821 => 2137 modulo2 on contract AvmTest with size 16 => 16 nested_call_to_add on contract AvmNestedCallsTest with size 862 => 756 nested_call_to_add_with_gas on contract AvmNestedCallsTest with size 929 => 799 nested_static_call_to_add on contract AvmNestedCallsTest with size 890 => 784 nested_static_call_to_set_storage on contract AvmNestedCallsTest with size 759 => 665 new_note_hash on contract AvmTest with size 47 => 11 new_nullifier on contract AvmAcvmInteropTest with size 47 => 11 new_nullifier on contract AvmNestedCallsTest with size 47 => 11 new_nullifier on contract AvmTest with size 47 => 11 new_nullifier_acvm on contract AvmAcvmInteropTest with size 47 => 11 note_hash_exists on contract AvmTest with size 65 => 17 nullifier_collision on contract AvmTest with size 82 => 12 nullifier_exists on contract AvmTest with size 103 => 17 on_card_played on contract CardGame with size 2386 => 2151 on_cards_claimed on contract CardGame with size 2176 => 1927 on_game_joined on contract CardGame with size 1972 => 1733 pay_refund on contract FPC with size 2052 => 1685 pay_refund_with_shielded_rebate on contract FPC with size 2138 => 1771 pedersen_hash on contract AvmTest with size 19 => 19 pedersen_hash_with_index on contract AvmTest with size 19 => 19 poseidon2_hash on contract AvmTest with size 1370 => 1370 prepare_fee on contract FPC with size 1643 => 1280 pub_call_public_fn on contract ImportTest with size 710 => 636 pub_entry_point on contract Parent with size 263 => 189 pub_entry_point_twice on contract Parent with size 497 => 339 pub_get_value on contract Child with size 174 => 22 pub_get_value on contract StaticChild with size 409 => 281 pub_illegal_inc_value on contract StaticChild with size 448 => 336 pub_inc_value on contract Child with size 175 => 45 pub_inc_value on contract StaticChild with size 175 => 45 pub_inc_value_internal on contract Child with size 552 => 340 pub_set_value on contract Child with size 108 => 30 pub_set_value on contract StaticChild with size 108 => 30 public_call on contract StaticParent with size 263 => 189 public_constructor on contract StatefulTest with size 1808 => 1399 public_delegate_set_value on contract Delegator with size 724 => 724 public_get_decimals on contract Token with size 557 => 411 public_get_name on contract Token with size 538 => 392 public_get_symbol on contract Token with size 546 => 400 public_get_value_from_child on contract StaticParent with size 759 => 685 public_nested_static_call on contract Parent with size 674 => 561 public_nested_static_call on contract StaticParent with size 1012 => 894 public_set_value on contract DelegatedOn with size 68 => 28 public_static_call on contract Parent with size 328 => 236 public_static_call on contract StaticParent with size 328 => 236 push_nullifier_public on contract InclusionProofs with size 285 => 117 read_storage_immutable on contract AvmInitializerTest with size 286 => 133 read_storage_list on contract AvmTest with size 101 => 62 read_storage_map on contract AvmTest with size 385 => 341 read_storage_single on contract AvmTest with size 66 => 27 register on contract KeyRegistry with size 6385 => 5041 repay_public on contract Lending with size 2141 => 1747 rotate_npk_m on contract KeyRegistry with size 2592 => 1843 send_l2_to_l1_msg on contract AvmTest with size 56 => 12 set_admin on contract Token with size 528 => 257 set_authorized on contract Auth with size 925 => 474 set_authorized_delay on contract Auth with size 679 => 400 set_minter on contract Token with size 865 => 559 set_opcode_big_field on contract AvmTest with size 19 => 19 set_opcode_small_field on contract AvmTest with size 13 => 13 set_opcode_u32 on contract AvmTest with size 13 => 13 set_opcode_u64 on contract AvmTest with size 13 => 13 set_opcode_u8 on contract AvmTest with size 13 => 13 set_portal on contract GasToken with size 434 => 272 set_price on contract PriceFeed with size 401 => 349 set_read_storage_single on contract AvmTest with size 122 => 42 set_storage_list on contract AvmTest with size 76 => 30 set_storage_map on contract AvmTest with size 409 => 355 set_storage_single on contract AvmNestedCallsTest with size 65 => 25 set_storage_single on contract AvmTest with size 65 => 25 set_value_twice_with_nested_first on contract Child with size 803 => 654 set_value_twice_with_nested_last on contract Child with size 791 => 654 set_value_with_two_nested_calls on contract Child with size 1308 => 1063 sha256_hash on contract AvmTest with size 47 => 47 shield on contract Token with size 2368 => 1809 shield on contract TokenBlacklist with size 3102 => 2315 spend_public_authwit on contract DocsExample with size 14 => 14 spend_public_authwit on contract EcdsaAccount with size 1008 => 637 spend_public_authwit on contract SchnorrAccount with size 770 => 541 spend_public_authwit on contract SchnorrHardcodedAccount with size 770 => 540 spend_public_authwit on contract SchnorrSingleKeyAccount with size 770 => 540 spend_public_authwit on contract Uniswap with size 749 => 486 start_game on contract CardGame with size 2518 => 2175 swap_public on contract Uniswap with size 7983 => 6584 test_authwit_send_money on contract AvmAcvmInteropTest with size 803 => 709 test_get_contract_instance on contract AvmTest with size 522 => 410 test_get_contract_instance_raw on contract AvmTest with size 159 => 83 test_nullifier_inclusion_from_public on contract InclusionProofs with size 332 => 121 to_radix_le on contract AvmTest with size 187 => 187 total_supply on contract Token with size 536 => 390 total_supply on contract TokenBlacklist with size 536 => 390 transfer_public on contract Token with size 3071 => 2512 transfer_public on contract TokenBlacklist with size 4491 => 3533 u128_addition_overflow on contract AvmTest with size 772 => 668 u128_from_integer_overflow on contract AvmTest with size 357 => 357 update_accumulator on contract Lending with size 8695 => 8358 update_leader on contract DocsExample with size 430 => 290 update_roles on contract TokenBlacklist with size 2058 => 1252 withdraw_public on contract Lending with size 1190 => 93 ``` </details> ## Summary\* This PR: - Creates a separate pass for "runtime separation" where we convert any Acir function called from brillig to a brillig function. After that pass, all functions have correct runtime, meaning they'll be converted to the runtime they hold. - Updates the inliner to only consider entry points all brillig functions called from ACIR and all brillig recursive functions, instead of all brillig functions With this change the inliner can correctly detect which brillig functions **must not** be inlined. This opens the door to allowing annotating brillig functions with inlining suggestions in the future. ## Additional Context ## Documentation\* Check one: - [x] No documentation needed. - [ ] Documentation included in this PR. - [ ] **[For Experimental Features]** Documentation to be submitted in a separate PR. # PR Checklist\* - [x] I have tested the changes locally. - [x] I have formatted the changes with [Prettier](https://prettier.io/) and/or `cargo fmt` on default settings.
noir-lang · May 29, 2024 · 69eca9b · 69eca9b
1 parent b545744
commit 69eca9b
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Showing 13 changed files with 531 additions and 55 deletions.
diff --git a/acvm-repo/brillig_vm/src/memory.rs b/acvm-repo/brillig_vm/src/memory.rs
@@ -294,6 +294,12 @@ impl<F: AcirField> Memory<F> {
     }
 
     pub fn read_slice(&self, addr: MemoryAddress, len: usize) -> &[MemoryValue<F>] {
+        // Allows to read a slice of uninitialized memory if the length is zero.
+        // Ideally we'd be able to read uninitialized memory in general (as read does)
+        // but that's not possible if we want to return a slice instead of owned data.
+        if len == 0 {
+            return &[];
+        }
         &self.inner[addr.to_usize()..(addr.to_usize() + len)]
     }
 

diff --git a/compiler/noirc_evaluator/src/ssa.rs b/compiler/noirc_evaluator/src/ssa.rs
@@ -58,8 +58,9 @@ pub(crate) fn optimize_into_acir(
     let ssa = SsaBuilder::new(program, print_passes, force_brillig_output, print_timings)?
         .run_pass(Ssa::defunctionalize, "After Defunctionalization:")
         .run_pass(Ssa::remove_paired_rc, "After Removing Paired rc_inc & rc_decs:")
-        .run_pass(Ssa::inline_functions, "After Inlining:")
+        .run_pass(Ssa::separate_runtime, "After Runtime Separation:")
         .run_pass(Ssa::resolve_is_unconstrained, "After Resolving IsUnconstrained:")
+        .run_pass(Ssa::inline_functions, "After Inlining:")
         // Run mem2reg with the CFG separated into blocks
         .run_pass(Ssa::mem2reg, "After Mem2Reg:")
         .run_pass(Ssa::as_slice_optimization, "After `as_slice` optimization")

diff --git a/compiler/noirc_evaluator/src/ssa/ir/dfg.rs b/compiler/noirc_evaluator/src/ssa/ir/dfg.rs
@@ -22,7 +22,7 @@ use noirc_errors::Location;
 /// its blocks, instructions, and values. This struct is largely responsible for
 /// owning most data in a function and handing out Ids to this data that can be
 /// shared without worrying about ownership.
-#[derive(Debug, Default)]
+#[derive(Debug, Default, Clone)]
 pub(crate) struct DataFlowGraph {
     /// All of the instructions in a function
     instructions: DenseMap<Instruction>,

diff --git a/compiler/noirc_evaluator/src/ssa/ir/function.rs b/compiler/noirc_evaluator/src/ssa/ir/function.rs
@@ -64,6 +64,13 @@ impl Function {
         Self { name, id, entry_block, dfg, runtime: RuntimeType::Acir(InlineType::default()) }
     }
 
+    /// Creates a new function as a clone of the one passed in with the passed in id.
+    pub(crate) fn clone_with_id(id: FunctionId, another: &Function) -> Self {
+        let dfg = another.dfg.clone();
+        let entry_block = another.entry_block;
+        Self { name: another.name.clone(), id, entry_block, dfg, runtime: another.runtime }
+    }
+
     /// The name of the function.
     /// Used exclusively for debugging purposes.
     pub(crate) fn name(&self) -> &str {

diff --git a/compiler/noirc_evaluator/src/ssa/ir/map.rs b/compiler/noirc_evaluator/src/ssa/ir/map.rs
@@ -115,7 +115,7 @@ impl std::fmt::Display for Id<super::instruction::Instruction> {
 /// access to indices is provided. Since IDs must be stable and correspond
 /// to indices in the internal Vec, operations that would change element
 /// ordering like pop, remove, swap_remove, etc, are not possible.
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub(crate) struct DenseMap<T> {
     storage: Vec<T>,
 }

diff --git a/compiler/noirc_evaluator/src/ssa/opt/inlining.rs b/compiler/noirc_evaluator/src/ssa/opt/inlining.rs
@@ -27,7 +27,7 @@ const RECURSION_LIMIT: u32 = 1000;
 impl Ssa {
     /// Inline all functions within the IR.
     ///
-    /// In the case of recursive functions, this will attempt
+    /// In the case of recursive Acir functions, this will attempt
     /// to recursively inline until the RECURSION_LIMIT is reached.
     ///
     /// Functions are recursively inlined into main until either we finish
@@ -41,6 +41,8 @@ impl Ssa {
     /// There are some attributes that allow inlining a function at a different step of codegen.
     /// Currently this is just `InlineType::NoPredicates` for which we have a flag indicating
     /// whether treating that inline functions. The default is to treat these functions as entry points.
+    ///
+    /// This step should run after runtime separation, since it relies on the runtime of the called functions being final.
     #[tracing::instrument(level = "trace", skip(self))]
     pub(crate) fn inline_functions(self) -> Ssa {
         Self::inline_functions_inner(self, true)
@@ -52,12 +54,17 @@ impl Ssa {
     }
 
     fn inline_functions_inner(mut self, no_predicates_is_entry_point: bool) -> Ssa {
+        let recursive_functions = find_all_recursive_functions(&self);
         self.functions = btree_map(
-            get_entry_point_functions(&self, no_predicates_is_entry_point),
+            get_functions_to_inline_into(&self, no_predicates_is_entry_point),
             |entry_point| {
-                let new_function =
-                    InlineContext::new(&self, entry_point, no_predicates_is_entry_point)
-                        .inline_all(&self);
+                let new_function = InlineContext::new(
+                    &self,
+                    entry_point,
+                    no_predicates_is_entry_point,
+                    recursive_functions.clone(),
+                )
+                .inline_all(&self);
                 (entry_point, new_function)
             },
         );
@@ -80,6 +87,8 @@ struct InlineContext {
     entry_point: FunctionId,
 
     no_predicates_is_entry_point: bool,
+    // We keep track of the recursive functions in the SSA to avoid inlining them in a brillig context.
+    recursive_functions: BTreeSet<FunctionId>,
 }
 
 /// The per-function inlining context contains information that is only valid for one function.
@@ -113,28 +122,101 @@ struct PerFunctionContext<'function> {
     inlining_entry: bool,
 }
 
-/// The entry point functions are each function we should inline into - and each function that
-/// should be left in the final program.
-/// This is the `main` function, any Acir functions with a [fold inline type][InlineType::Fold],
-/// and any brillig functions used.
-fn get_entry_point_functions(
+/// Utility function to find out the direct calls of a function.
+fn called_functions(func: &Function) -> BTreeSet<FunctionId> {
+    let mut called_function_ids = BTreeSet::default();
+    for block_id in func.reachable_blocks() {
+        for instruction_id in func.dfg[block_id].instructions() {
+            let Instruction::Call { func: called_value_id, .. } = &func.dfg[*instruction_id] else {
+                continue;
+            };
+
+            if let Value::Function(function_id) = func.dfg[*called_value_id] {
+                called_function_ids.insert(function_id);
+            }
+        }
+    }
+
+    called_function_ids
+}
+
+// Recursively explore the SSA to find the functions that end up calling themselves
+fn find_recursive_functions(
+    ssa: &Ssa,
+    current_function: FunctionId,
+    mut explored_functions: im::HashSet<FunctionId>,
+    recursive_functions: &mut BTreeSet<FunctionId>,
+) {
+    if explored_functions.contains(&current_function) {
+        recursive_functions.insert(current_function);
+        return;
+    }
+
+    let called_functions = called_functions(&ssa.functions[&current_function]);
+
+    explored_functions.insert(current_function);
+
+    for called_function in called_functions {
+        find_recursive_functions(
+            ssa,
+            called_function,
+            explored_functions.clone(),
+            recursive_functions,
+        );
+    }
+}
+
+fn find_all_recursive_functions(ssa: &Ssa) -> BTreeSet<FunctionId> {
+    let mut recursive_functions = BTreeSet::default();
+    find_recursive_functions(ssa, ssa.main_id, im::HashSet::default(), &mut recursive_functions);
+    recursive_functions
+}
+
+/// The functions we should inline into (and that should be left in the final program) are:
+///  - main
+///  - Any Brillig function called from Acir
+///  - Any Brillig recursive function (Acir recursive functions will be inlined into the main function)
+///  - Any Acir functions with a [fold inline type][InlineType::Fold],
+fn get_functions_to_inline_into(
     ssa: &Ssa,
     no_predicates_is_entry_point: bool,
 ) -> BTreeSet<FunctionId> {
-    let functions = ssa.functions.iter();
-    let mut entry_points = functions
-        .filter(|(_, function)| {
-            // If we have not already finished the flattening pass, functions marked
-            // to not have predicates should be marked as entry points.
-            let no_predicates_is_entry_point =
-                no_predicates_is_entry_point && function.is_no_predicates();
-            function.runtime().is_entry_point() || no_predicates_is_entry_point
+    let mut brillig_entry_points = BTreeSet::default();
+    let mut acir_entry_points = BTreeSet::default();
+
+    for (func_id, function) in ssa.functions.iter() {
+        if function.runtime() == RuntimeType::Brillig {
+            continue;
+        }
+
+        // If we have not already finished the flattening pass, functions marked
+        // to not have predicates should be marked as entry points.
+        let no_predicates_is_entry_point =
+            no_predicates_is_entry_point && function.is_no_predicates();
+        if function.runtime().is_entry_point() || no_predicates_is_entry_point {
+            acir_entry_points.insert(*func_id);
+        }
+
+        for called_function_id in called_functions(function) {
+            if ssa.functions[&called_function_id].runtime() == RuntimeType::Brillig {
+                brillig_entry_points.insert(called_function_id);
+            }
+        }
+    }
+
+    let brillig_recursive_functions: BTreeSet<_> = find_all_recursive_functions(ssa)
+        .into_iter()
+        .filter(|recursive_function_id| {
+            let function = &ssa.functions[&recursive_function_id];
+            function.runtime() == RuntimeType::Brillig
         })
-        .map(|(id, _)| *id)
-        .collect::<BTreeSet<_>>();
+        .collect();
 
-    entry_points.insert(ssa.main_id);
-    entry_points
+    std::iter::once(ssa.main_id)
+        .chain(acir_entry_points)
+        .chain(brillig_entry_points)
+        .chain(brillig_recursive_functions)
+        .collect()
 }
 
 impl InlineContext {
@@ -147,6 +229,7 @@ impl InlineContext {
         ssa: &Ssa,
         entry_point: FunctionId,
         no_predicates_is_entry_point: bool,
+        recursive_functions: BTreeSet<FunctionId>,
     ) -> InlineContext {
         let source = &ssa.functions[&entry_point];
         let mut builder = FunctionBuilder::new(source.name().to_owned(), entry_point);
@@ -157,6 +240,7 @@ impl InlineContext {
             entry_point,
             call_stack: CallStack::new(),
             no_predicates_is_entry_point,
+            recursive_functions,
         }
     }
 
@@ -391,18 +475,10 @@ impl<'function> PerFunctionContext<'function> {
             match &self.source_function.dfg[*id] {
                 Instruction::Call { func, arguments } => match self.get_function(*func) {
                     Some(func_id) => {
-                        let function = &ssa.functions[&func_id];
-                        // If we have not already finished the flattening pass, functions marked
-                        // to not have predicates should be marked as entry points unless we are inlining into brillig.
-                        let entry_point = &ssa.functions[&self.context.entry_point];
-                        let no_predicates_is_entry_point =
-                            self.context.no_predicates_is_entry_point
-                                && function.is_no_predicates()
-                                && !matches!(entry_point.runtime(), RuntimeType::Brillig);
-                        if function.runtime().is_entry_point() || no_predicates_is_entry_point {
-                            self.push_instruction(*id);
-                        } else {
+                        if self.should_inline_call(ssa, func_id) {
                             self.inline_function(ssa, *id, func_id, arguments);
+                        } else {
+                            self.push_instruction(*id);
                         }
                     }
                     None => self.push_instruction(*id),
@@ -412,6 +488,24 @@ impl<'function> PerFunctionContext<'function> {
         }
     }
 
+    fn should_inline_call(&self, ssa: &Ssa, called_func_id: FunctionId) -> bool {
+        let function = &ssa.functions[&called_func_id];
+
+        if let RuntimeType::Acir(inline_type) = function.runtime() {
+            // If the called function is acir, we inline if it's not an entry point
+
+            // If we have not already finished the flattening pass, functions marked
+            // to not have predicates should be marked as entry points.
+            let no_predicates_is_entry_point =
+                self.context.no_predicates_is_entry_point && function.is_no_predicates();
+            !inline_type.is_entry_point() && !no_predicates_is_entry_point
+        } else {
+            // If the called function is brillig, we inline only if it's into brillig and the function is not recursive
+            ssa.functions[&self.context.entry_point].runtime() == RuntimeType::Brillig
+                && !self.context.recursive_functions.contains(&called_func_id)
+        }
+    }
+
     /// Inline a function call and remember the inlined return values in the values map
     fn inline_function(
         &mut self,

diff --git a/compiler/noirc_evaluator/src/ssa/opt/mod.rs b/compiler/noirc_evaluator/src/ssa/opt/mod.rs
@@ -18,5 +18,6 @@ mod remove_bit_shifts;
 mod remove_enable_side_effects;
 mod remove_if_else;
 mod resolve_is_unconstrained;
+mod runtime_separation;
 mod simplify_cfg;
 mod unrolling;