[SPARK-19072][SQL] codegen of Literal should not output boxed value

## What changes were proposed in this pull request?

In https://github.com/apache/spark/pull/16402 we made a mistake that, when double/float is infinity, the `Literal` codegen will output boxed value and cause wrong result.

This PR fixes this by special handling infinity to not output boxed value.

## How was this patch tested?

new regression test

Author: Wenchen Fan <wenchen@databricks.com>

Closes #16469 from cloud-fan/literal.

1 files changed, 5 insertions, 0 deletions

diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/PredicateSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/PredicateSuite.scala
index 6fc3de178f..6fe295c3dd 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/PredicateSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/PredicateSuite.scala
@@ -324,4 +324,9 @@ class PredicateSuite extends SparkFunSuite with ExpressionEvalHelper {
       Literal.create(struct, structType),
       Literal.create(unsafeStruct, structType)), true)
   }
+
+  test("EqualTo double/float infinity") {
+    val infinity = Literal(Double.PositiveInfinity)
+    checkEvaluation(EqualTo(infinity, infinity), true)
+  }
 }