From 5cef325c11ce04a5da796fdaa854a90eb9fdcd4f Mon Sep 17 00:00:00 2001
From: sirasistant <sirasistant@gmail.com>
Date: Tue, 1 Apr 2025 09:47:50 +0000
Subject: [PATCH] fix: Transpile cmov

---
 avm-transpiler/src/transpile.rs               | 42 +++++++++++++++++++
 .../contracts/avm_test_contract/src/main.nr   |  9 ++++
 .../src/public/avm/avm_simulator.test.ts      | 17 ++++++++
 3 files changed, 68 insertions(+)

diff --git a/avm-transpiler/src/transpile.rs b/avm-transpiler/src/transpile.rs
index 085b48227951..e1da3bbdef29 100644
--- a/avm-transpiler/src/transpile.rs
+++ b/avm-transpiler/src/transpile.rs
@@ -322,6 +322,48 @@ pub fn brillig_to_avm(brillig_bytecode: &[BrilligOpcode<FieldElement>]) -> (Vec<
                     destination.to_usize() as u32,
                 ));
             }
+            BrilligOpcode::ConditionalMov { destination, source_a, source_b, condition } => {
+                // Move source_a to destination, if condition is true jump to the next brillig opcode, else move source_b to destination
+                avm_instrs.push(generate_mov_instruction(
+                    Some(
+                        AddressingModeBuilder::default()
+                            .direct_operand(source_a)
+                            .direct_operand(destination)
+                            .build(),
+                    ),
+                    source_a.to_usize() as u32,
+                    destination.to_usize() as u32,
+                ));
+
+                unresolved_jumps.insert(
+                    UnresolvedPCLocation {
+                        instruction_index: avm_instrs.len(),
+                        immediate_index: 0,
+                    },
+                    Label::BrilligPC { pc: brillig_pcs_to_avm_pcs.len() as u32 }, // We want to jump to the next brillig opcode
+                );
+
+                avm_instrs.push(AvmInstruction {
+                    opcode: AvmOpcode::JUMPI_32,
+                    indirect: Some(
+                        AddressingModeBuilder::default().direct_operand(condition).build(),
+                    ),
+                    operands: vec![make_operand(16, &condition.to_usize())],
+                    immediates: vec![make_unresolved_pc()],
+                    ..Default::default()
+                });
+
+                avm_instrs.push(generate_mov_instruction(
+                    Some(
+                        AddressingModeBuilder::default()
+                            .direct_operand(source_b)
+                            .direct_operand(destination)
+                            .build(),
+                    ),
+                    source_b.to_usize() as u32,
+                    destination.to_usize() as u32,
+                ));
+            }
             BrilligOpcode::Load { destination, source_pointer } => {
                 avm_instrs.push(generate_mov_instruction(
                     Some(
diff --git a/noir-projects/noir-contracts/contracts/avm_test_contract/src/main.nr b/noir-projects/noir-contracts/contracts/avm_test_contract/src/main.nr
index 768ad9df33e0..e71ec598826c 100644
--- a/noir-projects/noir-contracts/contracts/avm_test_contract/src/main.nr
+++ b/noir-projects/noir-contracts/contracts/avm_test_contract/src/main.nr
@@ -191,6 +191,15 @@ pub contract AvmTest {
         commitment
     }
 
+    #[public]
+    fn conditional_move(x: [Field; 1], y: [Field; 1], b: bool) -> [Field; 1] {
+        if b {
+            x
+        } else {
+            y
+        }
+    }
+
     /************************************************************************
      * Misc
      ************************************************************************/
diff --git a/yarn-project/simulator/src/public/avm/avm_simulator.test.ts b/yarn-project/simulator/src/public/avm/avm_simulator.test.ts
index 4465582819b2..a50aa55729ab 100644
--- a/yarn-project/simulator/src/public/avm/avm_simulator.test.ts
+++ b/yarn-project/simulator/src/public/avm/avm_simulator.test.ts
@@ -352,6 +352,23 @@ describe('AVM simulator: transpiled Noir contracts', () => {
     expect(results.output).toEqual(expectedResult);
   });
 
+  it('conditional move operations', async () => {
+    const calldata: Fr[] = [new Fr(27), new Fr(28), new Fr(1)];
+
+    const bytecode = getAvmTestContractBytecode('conditional_move');
+
+    let context = initContext({ env: initExecutionEnvironment({ calldata }) });
+    let results = await new AvmSimulator(context).executeBytecode(bytecode);
+    expect(results.reverted).toBe(false);
+    expect(results.output).toEqual([new Fr(27)]);
+
+    calldata[2] = new Fr(0);
+    context = initContext({ env: initExecutionEnvironment({ calldata }) });
+    results = await new AvmSimulator(context).executeBytecode(bytecode);
+    expect(results.reverted).toBe(false);
+    expect(results.output).toEqual([new Fr(28)]);
+  });
+
   describe('U128 addition and overflows', () => {
     it('U128 addition', async () => {
       const calldata: Fr[] = [