fix code gen for divide 0

Author: adrian-wang

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/CodeGenerator.scala

@@ -359,9 +359,24 @@ abstract class CodeGenerator[InType <: AnyRef, OutType <: AnyRef] extends Loggin
       case Add(e1, e2) =>      (e1, e2) evaluate { case (eval1, eval2) => q"$eval1 + $eval2" }
       case Subtract(e1, e2) => (e1, e2) evaluate { case (eval1, eval2) => q"$eval1 - $eval2" }
       case Multiply(e1, e2) => (e1, e2) evaluate { case (eval1, eval2) => q"$eval1 * $eval2" }
-      case Divide(e1, e2) =>   (e1, e2) evaluate {
-        case (eval1, eval2) => q"if ($eval2 == 0) null else $eval1 / $eval2"
-      }
+      case Divide(e1, e2) =>
+        val eval1 = expressionEvaluator(e1)
+        val eval2 = expressionEvaluator(e2)
+
+        eval1.code ++ eval2.code ++
+        q"""
+          var $nullTerm = false
+          var $primitiveTerm: ${termForType(e1.dataType)} = 0
+
+          if (${eval1.nullTerm} || ${eval2.nullTerm} ) {
+            $nullTerm = true
+          } else if (${eval2.primitiveTerm} == 0)
+            $nullTerm = true
+          else {
+            $nullTerm = false
+            $primitiveTerm = ${eval1.primitiveTerm} / ${eval2.primitiveTerm}
+          }
+         """.children
 
       case IsNotNull(e) =>
         val eval = expressionEvaluator(e)