@Test
  public void testSIMDGreaterThan() {
    long a;
    long b;

    a = 0; b = 0; assertEquals(a > b ? 1 : 0, (b - a) >>> 63);
    a = 1; b = 0; assertEquals(a > b ? 1 : 0, (b - a) >>> 63);
    a = 0; b = 1; assertEquals(a > b ? 1 : 0, (b - a) >>> 63);
  }
Test that correct VectorExpression classes are chosen for the
IF (expr1, expr2, expr3) conditional expression for integer, float,
boolean, timestamp and string input types. expr1 is always an input column expression
of type long. expr2 and expr3 can be column expressions or constants of other types
but must have the same type.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/TestVectorizationContext.java