feat: Remove unnecessary truncation of boolean multiplication (noir-l…

…ang#3122)

Co-authored-by: Tom French <git@tomfren.ch>

compiler/noirc_evaluator/src/ssa/ssa_gen/context.rs

@@ -774,7 +774,15 @@ fn operator_result_max_bit_size_to_truncate(
     match op {
         Add => Some(std::cmp::max(lhs_bit_size, rhs_bit_size) + 1),
         Subtract => Some(std::cmp::max(lhs_bit_size, rhs_bit_size) + 1),
-        Multiply => Some(lhs_bit_size + rhs_bit_size),
+        Multiply => {
+            if lhs_bit_size == 1 || rhs_bit_size == 1 {
+                // Truncation is unnecessary as multiplication by a boolean value cannot cause an overflow.
+                None
+            } else {
+                Some(lhs_bit_size + rhs_bit_size)
+            }
+        }
+
         ShiftLeft => {
             if let Some(rhs_constant) = dfg.get_numeric_constant(rhs) {
                 // Happy case is that we know precisely by how many bits the the integer will