chore: remove clones in optimizer/transformer code (#3037)

Co-authored-by: kevaundray <kevtheappdev@gmail.com>

acvm-repo/acvm/src/compiler/optimizers/general.rs

@@ -31,7 +31,7 @@ fn simplify_mul_terms(mut gate: Expression) -> Expression {
     let mut hash_map: IndexMap<(Witness, Witness), FieldElement> = IndexMap::new();
 
     // Canonicalize the ordering of the multiplication, lets just order by variable name
-    for (scale, w_l, w_r) in gate.mul_terms.clone().into_iter() {
+    for (scale, w_l, w_r) in gate.mul_terms.into_iter() {
         let mut pair = [w_l, w_r];
         // Sort using rust sort algorithm
         pair.sort();

acvm-repo/acvm/src/compiler/optimizers/mod.rs

@@ -23,20 +23,22 @@ pub fn optimize(acir: Circuit) -> (Circuit, AcirTransformationMap) {
 /// Applies [`ProofSystemCompiler`][crate::ProofSystemCompiler] independent optimizations to a [`Circuit`].
 pub(super) fn optimize_internal(acir: Circuit) -> (Circuit, AcirTransformationMap) {
     // General optimizer pass
-    let mut opcodes: Vec<Opcode> = Vec::new();
-    for opcode in acir.opcodes {
-        match opcode {
-            Opcode::Arithmetic(arith_expr) => {
-                opcodes.push(Opcode::Arithmetic(GeneralOptimizer::optimize(arith_expr)));
+    let opcodes: Vec<Opcode> = acir
+        .opcodes
+        .into_iter()
+        .map(|opcode| {
+            if let Opcode::Arithmetic(arith_expr) = opcode {
+                Opcode::Arithmetic(GeneralOptimizer::optimize(arith_expr))
+            } else {
+                opcode
             }
-            other_opcode => opcodes.push(other_opcode),
-        };
-    }
+        })
+        .collect();
     let acir = Circuit { opcodes, ..acir };
 
     // Track original acir opcode positions throughout the transformation passes of the compilation
     // by applying the modifications done to the circuit opcodes and also to the opcode_positions (delete and insert)
-    let acir_opcode_positions = acir.opcodes.iter().enumerate().map(|(i, _)| i).collect();
+    let acir_opcode_positions = (0..acir.opcodes.len()).collect();
 
     // Unused memory optimization pass
     let memory_optimizer = UnusedMemoryOptimizer::new(acir);

acvm-repo/acvm/src/compiler/optimizers/redundant_range.rs

@@ -74,13 +74,13 @@ impl RangeOptimizer {
 
         let mut new_order_list = Vec::with_capacity(order_list.len());
         let mut optimized_opcodes = Vec::with_capacity(self.circuit.opcodes.len());
-        for (idx, opcode) in self.circuit.opcodes.iter().enumerate() {
-            let (witness, num_bits) = match extract_range_opcode(opcode) {
+        for (idx, opcode) in self.circuit.opcodes.into_iter().enumerate() {
+            let (witness, num_bits) = match extract_range_opcode(&opcode) {
                 Some(range_opcode) => range_opcode,
                 None => {
                     // If its not the range opcode, add it to the opcode
                     // list and continue;
-                    optimized_opcodes.push(opcode.clone());
+                    optimized_opcodes.push(opcode);
                     new_order_list.push(order_list[idx]);
                     continue;
                 }
@@ -101,18 +101,11 @@ impl RangeOptimizer {
             if is_lowest_bit_size {
                 already_seen_witness.insert(witness);
                 new_order_list.push(order_list[idx]);
-                optimized_opcodes.push(opcode.clone());
+                optimized_opcodes.push(opcode);
             }
         }
 
-        (
-            Circuit {
-                current_witness_index: self.circuit.current_witness_index,
-                opcodes: optimized_opcodes,
-                ..self.circuit
-            },
-            new_order_list,
-        )
+        (Circuit { opcodes: optimized_opcodes, ..self.circuit }, new_order_list)
     }
 }
 

acvm-repo/acvm/src/compiler/optimizers/unused_memory.rs

@@ -42,16 +42,16 @@ impl UnusedMemoryOptimizer {
     ) -> (Circuit, Vec<usize>) {
         let mut new_order_list = Vec::with_capacity(order_list.len());
         let mut optimized_opcodes = Vec::with_capacity(self.circuit.opcodes.len());
-        for (idx, opcode) in self.circuit.opcodes.iter().enumerate() {
+        for (idx, opcode) in self.circuit.opcodes.into_iter().enumerate() {
             match opcode {
                 Opcode::MemoryInit { block_id, .. }
-                    if self.unused_memory_initializations.contains(block_id) =>
+                    if self.unused_memory_initializations.contains(&block_id) =>
                 {
                     // Drop opcode
                 }
                 _ => {
                     new_order_list.push(order_list[idx]);
-                    optimized_opcodes.push(opcode.clone());
+                    optimized_opcodes.push(opcode);
                 }
             }
         }

acvm-repo/acvm/src/compiler/transformers/mod.rs

@@ -76,13 +76,13 @@ pub(super) fn transform_internal(
     // maps a normalized expression to the intermediate variable which represents the expression, along with its 'norm'
     // the 'norm' is simply the value of the first non zero coefficient in the expression, taken from the linear terms, or quadratic terms if there is none.
     let mut intermediate_variables: IndexMap<Expression, (FieldElement, Witness)> = IndexMap::new();
-    for (index, opcode) in acir.opcodes.iter().enumerate() {
+    for (index, opcode) in acir.opcodes.into_iter().enumerate() {
         match opcode {
             Opcode::Arithmetic(arith_expr) => {
                 let len = intermediate_variables.len();
 
                 let arith_expr = transformer.transform(
-                    arith_expr.clone(),
+                    arith_expr,
                     &mut intermediate_variables,
                     &mut next_witness_index,
                 );
@@ -104,7 +104,7 @@ pub(super) fn transform_internal(
                     transformed_opcodes.push(Opcode::Arithmetic(opcode));
                 }
             }
-            Opcode::BlackBoxFuncCall(func) => {
+            Opcode::BlackBoxFuncCall(ref func) => {
                 match func {
                     acir::circuit::opcodes::BlackBoxFuncCall::AND { output, .. }
                     | acir::circuit::opcodes::BlackBoxFuncCall::XOR { output, .. } => {
@@ -146,9 +146,9 @@ pub(super) fn transform_internal(
                 }
 
                 new_acir_opcode_positions.push(acir_opcode_positions[index]);
-                transformed_opcodes.push(opcode.clone());
+                transformed_opcodes.push(opcode);
             }
-            Opcode::Directive(directive) => {
+            Opcode::Directive(ref directive) => {
                 match directive {
                     Directive::Quotient(quotient_directive) => {
                         transformer.mark_solvable(quotient_directive.q);
@@ -166,14 +166,14 @@ pub(super) fn transform_internal(
                     }
                 }
                 new_acir_opcode_positions.push(acir_opcode_positions[index]);
-                transformed_opcodes.push(opcode.clone());
+                transformed_opcodes.push(opcode);
             }
             Opcode::MemoryInit { .. } => {
                 // `MemoryInit` does not write values to the `WitnessMap`
                 new_acir_opcode_positions.push(acir_opcode_positions[index]);
-                transformed_opcodes.push(opcode.clone());
+                transformed_opcodes.push(opcode);
             }
-            Opcode::MemoryOp { op, .. } => {
+            Opcode::MemoryOp { ref op, .. } => {
                 for (_, witness1, witness2) in &op.value.mul_terms {
                     transformer.mark_solvable(*witness1);
                     transformer.mark_solvable(*witness2);
@@ -182,9 +182,9 @@ pub(super) fn transform_internal(
                     transformer.mark_solvable(*witness);
                 }
                 new_acir_opcode_positions.push(acir_opcode_positions[index]);
-                transformed_opcodes.push(opcode.clone());
+                transformed_opcodes.push(opcode);
             }
-            Opcode::Brillig(brillig) => {
+            Opcode::Brillig(ref brillig) => {
                 for output in &brillig.outputs {
                     match output {
                         BrilligOutputs::Simple(w) => transformer.mark_solvable(*w),
@@ -196,7 +196,7 @@ pub(super) fn transform_internal(
                     }
                 }
                 new_acir_opcode_positions.push(acir_opcode_positions[index]);
-                transformed_opcodes.push(opcode.clone());
+                transformed_opcodes.push(opcode);
             }
         }
     }