Add sub test. (#2577)

Co-authored-by: Georg Wiese <[email protected]>

Author: chriseth

executor/src/witgen/jit/interpreter.rs

@@ -785,7 +785,7 @@ mod test {
     };
 
     use powdr_ast::analyzed::Analyzed;
-    use powdr_number::{FieldElement, GoldilocksField, LargeInt};
+    use powdr_number::{BabyBearField, FieldElement, GoldilocksField, LargeInt};
 
     use bit_vec::BitVec;
     use itertools::Itertools;
@@ -1061,4 +1061,36 @@ namespace arith(8);
             &[GoldilocksField::from(7), GoldilocksField::from(0)]
         );
     }
+
+    #[test]
+    fn add_sub_bb() {
+        let pil = read_to_string("../test_data/pil/add_sub_bb.pil").unwrap();
+        let (analyzed, fixed_col_vals) = read_pil::<BabyBearField>(&pil);
+        let fixed_data = FixedData::new(&analyzed, &fixed_col_vals, &[], Default::default(), 0);
+        let fixed_data = global_constraints::set_global_constraints(fixed_data);
+
+        // First try to compute the "gt" flag.
+        let interpreter_gt =
+            TestInterpreter::new(&analyzed, &fixed_data, "main_add_sub", 4, 1, &|_| {
+                Err("Query not implemented".to_string())
+            });
+        interpreter_gt.test(&[1, 2, 3, 4, 0], &[1, 2, 3, 4, 1]);
+        interpreter_gt.test(&[3, 0, 2, 4, 0], &[3, 0, 2, 4, 0]);
+        interpreter_gt.test(&[5, 2, 0, 4, 0], &[5, 2, 0, 4, 0]);
+
+        // Then check that it also works if the result is already provided.
+        let interpreter_gt =
+            TestInterpreter::new(&analyzed, &fixed_data, "main_add_sub", 5, 0, &|_| {
+                Err("Query not implemented".to_string())
+            });
+        interpreter_gt.test(&[1, 2, 3, 4, 1], &[1, 2, 3, 4, 1]);
+        interpreter_gt.test(&[3, 0, 2, 4, 0], &[3, 0, 2, 4, 0]);
+        interpreter_gt.test(&[5, 2, 0, 4, 0], &[5, 2, 0, 4, 0]);
+
+        // This should actually panic, but it does not, because
+        // A_h is assigned a value outside of the two-byte range.
+        // We do not detect this because lookups that only result
+        // in range constraints are removed.
+        interpreter_gt.test(&[1, 2, 3, 4, 0], &[1, 2, 3, 4, 0]);
+    }
 }

test_data/pil/add_sub_bb.pil

@@ -0,0 +1,28 @@
+// A compiled version of "add_sub.asm" for babybear.
+namespace main(32..4096);
+    // Dummy connection constraint
+    col witness i1, i2, i3, i4, i5;
+    [i1, i2, i3, i4, i5] is [main_add_sub::C_h, main_add_sub::C_l, main_add_sub::B_h, main_add_sub::B_l, main_add_sub::carry32];
+namespace main_add_sub(32..4096);
+    col witness carry16;
+    main_add_sub::carry16 * (1 - main_add_sub::carry16) = 0;
+    col witness carry32;
+    main_add_sub::carry32 * (1 - main_add_sub::carry32) = 0;
+    col witness A_h;
+    col witness A_l;
+    col witness B_h;
+    col witness B_l;
+    col witness C_h;
+    col witness C_l;
+    main_add_sub::A_l + main_add_sub::B_l = main_add_sub::C_l + main_add_sub::carry16 * 65536;
+    main_add_sub::A_h + main_add_sub::B_h + main_add_sub::carry16 = main_add_sub::C_h + main_add_sub::carry32 * 65536;
+    col witness sel;
+    main_add_sub::sel * (1 - main_add_sub::sel) = 0;
+    [main_add_sub::A_l] in [main_byte2::BYTE2];
+    [main_add_sub::A_h] in [main_byte2::BYTE2];
+    [main_add_sub::B_l] in [main_byte2::BYTE2];
+    [main_add_sub::B_h] in [main_byte2::BYTE2];
+    [main_add_sub::C_l] in [main_byte2::BYTE2];
+    [main_add_sub::C_h] in [main_byte2::BYTE2];
+namespace main_byte2(65536);
+    col fixed BYTE2(i) { i & 65535_int };