[SPARK-9549][SQL] fix bugs in expressions

JIRA: https://issues.apache.org/jira/browse/SPARK-9549

This PR fix the following bugs:
1.  `UnaryMinus`'s codegen version would fail to compile when the input is `Long.MinValue`
2.  `BinaryComparison` would fail to compile in codegen mode when comparing Boolean types.
3.  `AddMonth` would fail if passed a huge negative month, which would lead accessing negative index of `monthDays` array.
4.  `Nanvl` with different type operands.

Author: Yijie Shen <henry.yijieshen@gmail.com>

Closes #7882 from yjshen/minor_bug_fix and squashes the following commits:

41bbd2c [Yijie Shen] fix bug in Nanvl type coercion
3dee204 [Yijie Shen] address comments
4fa5de0 [Yijie Shen] fix bugs in expressions

4 files changed, 18 insertions, 4 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/HiveTypeCoercion.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/HiveTypeCoercion.scala
index 603afc4032..422d423747 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/HiveTypeCoercion.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/HiveTypeCoercion.scala
@@ -562,6 +562,11 @@ object HiveTypeCoercion {
           case Some(finalDataType) => Coalesce(es.map(Cast(_, finalDataType)))
           case None => c
         }
+
+      case NaNvl(l, r) if l.dataType == DoubleType && r.dataType == FloatType =>
+        NaNvl(l, Cast(r, DoubleType))
+      case NaNvl(l, r) if l.dataType == FloatType && r.dataType == DoubleType =>
+        NaNvl(Cast(l, DoubleType), r)
     }
   }
 
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/arithmetic.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/arithmetic.scala
index 6f8f4dd230..0891b55494 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/arithmetic.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/arithmetic.scala
@@ -36,7 +36,14 @@ case class UnaryMinus(child: Expression) extends UnaryExpression with ExpectsInp
 
   override def genCode(ctx: CodeGenContext, ev: GeneratedExpressionCode): String = dataType match {
     case dt: DecimalType => defineCodeGen(ctx, ev, c => s"$c.unary_$$minus()")
-    case dt: NumericType => defineCodeGen(ctx, ev, c => s"(${ctx.javaType(dt)})(-($c))")
+    case dt: NumericType => nullSafeCodeGen(ctx, ev, eval => {
+      val originValue = ctx.freshName("origin")
+      // codegen would fail to compile if we just write (-($c))
+      // for example, we could not write --9223372036854775808L in code
+      s"""
+        ${ctx.javaType(dt)} $originValue = (${ctx.javaType(dt)})($eval);
+        ${ev.primitive} = (${ctx.javaType(dt)})(-($originValue));
+      """})
     case dt: CalendarIntervalType => defineCodeGen(ctx, ev, c => s"$c.negate()")
   }
 
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/predicates.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/predicates.scala
index ab7d3afce8..b69bbabee7 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/predicates.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/predicates.scala
@@ -227,6 +227,7 @@ abstract class BinaryComparison extends BinaryOperator with Predicate {
 
   override def genCode(ctx: CodeGenContext, ev: GeneratedExpressionCode): String = {
     if (ctx.isPrimitiveType(left.dataType)
+        && left.dataType != BooleanType // java boolean doesn't support > or < operator
         && left.dataType != FloatType
         && left.dataType != DoubleType) {
       // faster version
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala
index 6a98f4d9c5..f645eb5f7b 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala
@@ -614,8 +614,9 @@ object DateTimeUtils {
    */
   def dateAddMonths(days: Int, months: Int): Int = {
     val absoluteMonth = (getYear(days) - YearZero) * 12 + getMonth(days) - 1 + months
-    val currentMonthInYear = absoluteMonth % 12
-    val currentYear = absoluteMonth / 12
+    val nonNegativeMonth = if (absoluteMonth >= 0) absoluteMonth else 0
+    val currentMonthInYear = nonNegativeMonth % 12
+    val currentYear = nonNegativeMonth / 12
     val leapDay = if (currentMonthInYear == 1 && isLeapYear(currentYear + YearZero)) 1 else 0
     val lastDayOfMonth = monthDays(currentMonthInYear) + leapDay
 
@@ -626,7 +627,7 @@ object DateTimeUtils {
     } else {
       dayOfMonth
     }
-    firstDayOfMonth(absoluteMonth) + currentDayInMonth - 1
+    firstDayOfMonth(nonNegativeMonth) + currentDayInMonth - 1
   }
 
   /**