Handle special case for round

Author: namannimmo10

integration_tests/test_builtin_round.py

@@ -16,6 +16,11 @@ def test_round():
     print(round(f))
     assert round(13.001) == 13
     assert round(-40.49999) == -40
+    assert round(0.5) == 0
+    assert round(-0.5) == 0
+    assert round(1.5) == 2
+    assert round(50.5) == 50
+    assert round(56.78) == 57
 
 
 test_round()

src/lpython/semantics/python_comptime_eval.h

@@ -420,8 +420,10 @@ struct PythonIntrinsicProcedures {
         ASR::ttype_t* t = ASRUtils::expr_type(expr);
         if (ASRUtils::is_real(*t)) {
             double rv = ASR::down_cast<ASR::ConstantReal_t>(expr)->m_r;
-            int64_t ival = round(rv);
-            return ASR::down_cast<ASR::expr_t>(make_ConstantInteger_t(al, loc, ival, type));
+            int64_t rounded = round(rv);
+            if (fabs(rv-rounded) == 0.5)
+                rounded = 2.0*round(rv/2.0);
+            return ASR::down_cast<ASR::expr_t>(make_ConstantInteger_t(al, loc, rounded, type));
         } else {
             throw SemanticError("round() argument must be float for now, not '" +
                 ASRUtils::type_to_str(t) + "'", loc);