Incorrect results for FILTER *** BY ( *** OR ***) with FilterLogicExpressionSimplifier optimizer turned on

An example for this bug:

cat weird.txt
1,a
2,b
3,c

When running pig with the following statements:

A = LOAD 'weird.txt' using PigStorage(',') AS (col1:int,col2);
B = FILTER A BY ((col1==1) OR (col1 != 1));
DUMP B;

I expect to get the result of all three rows back, but I receive only two rows.

(2,b)
(3,c)

When we start pig with optimizer turning off.

pig -optimizer_off All

With optimizer turning off, we get the expected results and I get three rows for the same statements.

(1,a)
(2,b)
(3,c)

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This bug was test on:

pig-0.9.1,
pig-0.9.0,
pig-0.8.1,
pig-0.8.0

All produced same incorrect results.

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When looked at the logical plan for this example, we found FilterlogicExpressionSimplifier optimizer produced incorrect logical plan. So we guess the bug is caused by FilterlogicExpressionSimplifier optimizer.