feat(performance): Use unchecked ops based upon known induction variables

compiler/noirc_evaluator/src/ssa/ir/instruction/binary.rs

@@ -39,9 +39,9 @@
     Or,
     /// Bitwise xor (^)
     Xor,
     /// Bitshift left (<<)
     Shl,
     /// Bitshift right (>>)
     Shr,
 }
 
@@ -107,7 +107,7 @@
         }
 
         let operator = if lhs_type == NumericType::NativeField {
             // Unchecked operations between fields or bools don't make sense, so we convert those to non-unchecked
             // to reduce noise and confusion in the generated SSA.
             match operator {
                 BinaryOp::Add { unchecked: true } => BinaryOp::Add { unchecked: false },
@@ -116,7 +116,7 @@
                 _ => operator,
             }
         } else if lhs_type == NumericType::bool() {
             // Unchecked mul between bools doesn't make sense, so we convert that to non-unchecked
             if let BinaryOp::Mul { unchecked: true } = operator {
                 BinaryOp::Mul { unchecked: false }
             } else {
@@ -289,7 +289,7 @@
                 }
                 if lhs_type == NumericType::bool() {
                     // Boolean AND is equivalent to multiplication, which is a cheaper operation.
                     // (mul unchecked because these are bools so it doesn't matter really)
                     let instruction =
                         Instruction::binary(BinaryOp::Mul { unchecked: true }, lhs, rhs);
                     return SimplifyResult::SimplifiedToInstruction(instruction);
@@ -563,6 +563,24 @@
             BinaryOp::Shr => |x, y| Some(x >> y),
         }
     }
+
+    pub(crate) fn into_unchecked(self) -> Self {
+        match self {
+            BinaryOp::Add { .. } => BinaryOp::Add { unchecked: true },
+            BinaryOp::Sub { .. } => BinaryOp::Sub { unchecked: true },
+            BinaryOp::Mul { .. } => BinaryOp::Mul { unchecked: true },
+            _ => self,
+        }
+    }
+
+    pub(crate) fn is_unchecked(self) -> bool {
+        match self {
+            BinaryOp::Add { unchecked }
+            | BinaryOp::Sub { unchecked }
+            | BinaryOp::Mul { unchecked } => unchecked,
+            _ => true,
+        }
+    }
 }
 
 #[cfg(test)]