diff --git a/scripts/aby_tests/c_test_aby.py b/scripts/aby_tests/c_test_aby.py
index 473d57bf..3a8d59d4 100755
--- a/scripts/aby_tests/c_test_aby.py
+++ b/scripts/aby_tests/c_test_aby.py
@@ -31,7 +31,7 @@ if __name__ == "__main__":
         cryptonets_tests + \
         histogram_tests
 
-    tests = histogram_tests
+    tests = biomatch_tests
 
     # TODO: add support unsigned + int promotion
     # unsigned_arithmetic_tests + \
diff --git a/scripts/build_mpc_c_test.zsh b/scripts/build_mpc_c_test.zsh
index edab8b8a..c8ab8837 100755
--- a/scripts/build_mpc_c_test.zsh
+++ b/scripts/build_mpc_c_test.zsh
@@ -36,10 +36,7 @@ function mpc_test_bool  {
     RUST_BACKTRACE=1 measure_time $BIN --parties $parties $cpath mpc --cost-model "hycc" --selection-scheme "b"
 }
 
-
-mpc_test 2 ./examples/C/mpc/benchmarks/histogram/histogram.c
-
-# mpc_test 2 ./examples/C/mpc/playground.c
+mpc_test 2 ./examples/C/mpc/playground.c
 
 # # build mpc arithmetic tests
 # mpc_test 2 ./examples/C/mpc/unit_tests/arithmetic_tests/2pc_add.c
@@ -131,6 +128,10 @@ mpc_test 2 ./examples/C/mpc/benchmarks/histogram/histogram.c
 # mpc_test 2 ./examples/C/mpc/benchmarks/mnist/mnist.c
 # mpc_test 2 ./examples/C/mpc/benchmarks/cryptonets/cryptonets.c
 
+# # build OPA benchmarks
+# mpc_test 2 ./examples/C/mpc/benchmarks/histogram/histogram.c
+
+
 
 # # build hycc benchmarks bool-only
 # mpc_test_bool 2 ./examples/C/mpc/benchmarks/biomatch/2pc_biomatch.c
diff --git a/src/ir/term/mod.rs b/src/ir/term/mod.rs
index 4afef552..f49971fd 100644
--- a/src/ir/term/mod.rs
+++ b/src/ir/term/mod.rs
@@ -319,6 +319,18 @@ impl Display for Op {
     }
 }
 
+impl Ord for Op {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        self.cmp(&other)
+    }
+}
+
+impl PartialOrd for Op {
+    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
 /// Boolean n-ary operator
 pub enum BoolNaryOp {
@@ -2001,17 +2013,6 @@ impl Computation {
     }
 }
 
-// #[derive(Clone, Debug, PartialOrd, Ord, PartialEq, Eq, Hash)]
-// /// A function definition.
-// pub struct FuncDef {
-//     /// Name of function
-//     pub name: String,
-//     /// Type signature of function parameters
-//     pub params: BTreeMap<String, Sort>,
-//     /// Return type of function
-//     pub ret_ty: Vec<Sort>,
-// }
-
 #[derive(Clone, Debug, Default, PartialEq)]
 /// A map of IR computations.
 pub struct Functions {
diff --git a/src/target/aby/call_site_similarity.rs b/src/target/aby/call_site_similarity.rs
index c3542bcf..652a7c61 100644
--- a/src/target/aby/call_site_similarity.rs
+++ b/src/target/aby/call_site_similarity.rs
@@ -5,7 +5,7 @@ use crate::ir::term::*;
 use std::collections::HashMap;
 
 /// Determine if call sites are similar based on input and output arguments to the call site
-pub fn call_site_similarity(fs: &Functions) {
+pub fn call_site_similarity(fs: &Functions) -> Vec<Vec<Term>> {
     // Return a TermMap of (call) --> id for which calls are similar
     // Maybe return a vector of vector of terms
 
@@ -61,21 +61,24 @@ pub fn call_site_similarity(fs: &Functions) {
 
     // Clean input and output terms
     let mut call_sites: HashMap<(Vec<Op>, Vec<Op>), Vec<Term>> = HashMap::new();
-    
 
     for (c, (i, o)) in call_term_map {
-        println!("function: {}", c);
-        println!(
-            "inputs: {:?}",
-            i.iter().map(|x| x.op.clone()).collect::<Vec<Op>>()
-        );
-        println!(
-            "outputs: {:?}\n",
-            o.iter().map(|x| x.op.clone()).collect::<Vec<Op>>()
-        );
+        let input_ops = i.iter().map(|x| x.op.clone()).collect::<Vec<Op>>();
+        let mut output_ops = o.iter().map(|x| x.op.clone()).collect::<Vec<Op>>();
+        output_ops.sort();
+
+        let key = (input_ops, output_ops);
+
+        // longest prefix matching?
+
+        // edit distance?
+
+        if call_sites.contains_key(&key) {
+            call_sites.get_mut(&key).unwrap().push(c);
+        } else {
+            call_sites.insert(key, vec![c]);
+        }
     }
-    todo!();
 
-
-    // return call_sites values 
+    return call_sites.into_values().collect::<Vec<_>>();
 }
diff --git a/src/target/aby/trans.rs b/src/target/aby/trans.rs
index 69455a05..ce8f5c04 100644
--- a/src/target/aby/trans.rs
+++ b/src/target/aby/trans.rs
@@ -1126,7 +1126,7 @@ impl<'a> ToABY<'a> {
 /// Convert this (IR) `ir` to ABY.
 pub fn to_aby(ir: Functions, path: &Path, lang: &str, cm: &str, ss: &str) {
     // Call site similarity
-    // call_site_similarity(&ir);
+    call_site_similarity(&ir);
 
     // Protocal Assignments
     let mut s_map: HashMap<String, SharingMap> = HashMap::new();